cyclin-d1 and Reperfusion-Injury

Remote ischemic pre-conditioning (RIPC) protects against ischemia/reperfusion (I/R) injury. However, the mechanisms underlying this protection remain unclear. In the present study, we investigated the role of Janus-activated kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway and cell cycle arrest, and their relationship with neuronal apoptosis following RIPC.. A rat cerebral I/R injury model was induced by middle cerebral artery occlusion (MCAO), and AG490 was used to investigate the mechanisms of RIPC. p-JAK2-, p-STAT3-, cyclin D1-, and cyclin-dependent kinase 6 (CDK6) expression was assessed by Western blotting and immunofluorescence staining.. RIPC reduced the infarct volume, improved neurological function, and increased neuronal survival. Furthermore, p-JAK2 and p-STAT3 were detected during the initial phase of reperfusion; the expression levels were significantly increased at 3 and 24 h after reperfusion and were suppressed by RIPC. Additionally, the MCAO-induced upregulation of the cell cycle regulators cyclin D1 and CDK6 was ameliorated by RIPC. Meanwhile, cyclin D1 and CDK6 were colocalized with p-STAT3 in the ischemic brain.. RIPC ameliorates the induction of the JAK2/STAT3 pathway and cell cycle regulators cyclin D1 and CDK6 by MCAO, and this net inhibition of cell cycle re-entry by RIPC is associated with downregulation of STAT3 phosphorylation.

Topics: Animals; Brain Ischemia; Cell Cycle; Cyclin D1; Hindlimb; Infarction, Middle Cerebral Artery; Ischemic Preconditioning; Janus Kinase 2; Rats; Reperfusion Injury; Signal Transduction; STAT3 Transcription Factor

Liver ischemia-reperfusion injury (IRI) is an inevitable process during liver transplantation, hemorrhagic shock, resection, and other liver surgeries. It is an important cause of postoperative liver dysfunction and increased medical costs. The protective effects of the vagus nerve on hepatic IRI have been reported, but the underlying mechanism has not been fully understood. We established a hepatic vagotomy (Hv) mouse model to study the effect of the vagus on liver IRI and to explore the underlying mechanism. Liver IRI was more serious in mice with Hv, which showed higher serum ALT and AST activities and histopathological changes. Further experiments confirmed that Hv significantly downregulated the expression of IL-22 protein and mRNA in the liver, blocking the activation of the STAT3 pathway. The STAT3 pathway in the livers of Hv mice was significantly activated, and liver injury was clearly alleviated after treatment with exogenous IL-22 recombinant protein. In conclusion, Hv can aggravate hepatic IRI, and its mechanism may be related to inhibition of IL-22 expression and downregulation of the STAT3 pathway in the liver.

Topics: Animals; Cyclin D1; Disease Models, Animal; Disease Progression; Disease Susceptibility; Gene Expression; Immunohistochemistry; Interleukin-22; Interleukins; Liver Diseases; Male; Mice; Nerve Block; Phosphorylation; Reperfusion Injury; STAT3 Transcription Factor; Vagus Nerve

Remifentanil is a potent, short-acting opioid analgesic drug that can protect tissues from ischemia and reperfusion injury though anti-inflammatory effects. However, the utility of remifentanil in liver regeneration after hepatectomy is not known. Using a 70% hepatectomy mouse model (PHx), we found that preconditioning animals with 4 μg/kg remifentanil enhanced liver regeneration through supporting hepatocyte proliferation but not through anti-inflammatory effects. These effects were also phenocopied in vitro where 40 mM remifentanil promoted the proliferation of primary mouse hepatocyte cultures. We further identified that remifentanil treatment increased the expression of β-arrestin 2 in vivo and in vitro. Demonstrating specificity, remifentanil preconditioning failed to promote liver regeneration in liver-specific β-arrestin 2 knockout (CKO) mice subjected to PHx. While remifentanil increased the expression of activated (phosphorylated)-ERK and cyclin D1 in PHx livers, their levels were not significantly changed in remifentanil-treated CKO mice nor in WT mice pretreated with the ERK inhibitor U0126. Our findings suggest that remifentanil promotes liver regeneration via upregulation of a β-arrestin 2/ERK/cyclin D1 axis, with implications for improving regeneration process after hepatectomy.

Topics: Analgesics, Opioid; Animals; beta-Arrestin 2; Cell Proliferation; Cells, Cultured; Cyclin D1; Disease Models, Animal; Hepatectomy; Hepatocytes; Liver Regeneration; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Remifentanil; Reperfusion Injury; Up-Regulation

Buyang Huanwu Decoction (BHD), a classic traditional Chinese medicine (TCM) formula, has been used for recovering neurological dysfunctions and treating post-stroke disability in China for 200 years. In the present study, we investigated the effects of BHD on inhibiting neuronal apoptosis, promoting proliferation and differentiation of neural stem cells (NSCs) and neurite formation and enhancing learning and memory functional recovery in an experimental rat ischemic stroke model. BHD significantly reduced infarct volume and decreased cell apoptosis in the ischemic brain. BHD enhanced neuronal cell viability in vitro. BHD dose-dependently promoted the proliferation of NSCs in ischemic rat brains in vivo. Moreover, BHD promoted neuronal and astrocyte differentiation in primary cultured NSCs in vitro. Water maze test revealed that BHD promoted the recovery of learning function but not memory functions in the transient ischemic rats. We then investigated the changes of the cellular signaling molecules by using two-dimension (2D) gel electrophoresis and focused on the PI3K/Akt/Bad and Jak2/Stat3/cyclin D1signaling pathway to uncover its underlying mechanisms for its neuroprotective and neurogenetic effects. BHD significantly upregulated the expression of p-PI3K, p-Akt, and p-Bad as well as the expression of p-Jak, p-Stat3, and cyclin D1 in vitro and in vivo. In addition, BHD upregulated Hes1 and downregulated cav-1 in vitro and in vivo. Taken together, these results suggest that BHD has neuroprotective effects and neurogenesis-promoting effects via activating PI3K/Akt/Bad and Jak2/Stat3/Cyclin D1 signaling pathways. Graphical Abstract Buyang Huanwu Decoction (BHD) activates the PI3K-AKT-BAD pathway in the ischemic brain for neuroprotection. BHD also activates JAK2/STAT3/Cyclin D1 signaling cascades for promoting neurogenesis in the hippocampus of post-ischemic brains. Moreover, BHD inhibits the expression of caveolin-1 and increases the expression of HES1 for promoting neuronal differentiation. The neuroprotective and neurogenesis-promoting effects in the hippocampus of post-ischemic brains promote learning ability.

Topics: 14-3-3 Proteins; Animals; Apoptosis; Astrocytes; Axons; bcl-Associated Death Protein; Caveolin 1; Cell Differentiation; Cell Proliferation; Cyclin D1; Down-Regulation; Drugs, Chinese Herbal; ErbB Receptors; Ischemic Attack, Transient; Ischemic Stroke; Janus Kinase 2; Male; Memory; Neural Stem Cells; Neuritis; Neurogenesis; Neuroprotection; Neuroprotective Agents; PC12 Cells; Phosphatidylinositol 3-Kinases; Proteomics; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Recovery of Function; Reperfusion Injury; Signal Transduction; STAT3 Transcription Factor; Transcription Factor HES-1; Up-Regulation; Xanthenes

Topics: Acute Kidney Injury; Animals; Apoptosis; Cell Hypoxia; Cell Proliferation; Cyclin D1; Humans; Kidney; Malondialdehyde; MicroRNAs; Proto-Oncogene Proteins c-myc; Rats; Reactive Oxygen Species; Reperfusion Injury; RNA, Long Noncoding; Superoxide Dismutase; Up-Regulation; Wnt Signaling Pathway

Hepatic ischemia/reperfusion injury (IRI) is a common cause of morbidity and mortality in liver transplantation settings and involves severe cell death and inflammatory responses. MicroRNA-191 has recently been reported to be abnormally expressed in hepatocellular carcinoma and other liver diseases in the regulation of important cellular processes. However, little is known about its function and molecular mechanism in IRI. Here, we demonstrate that miR-191 is significantly upregulated in a cultured cell line during hypoxia/reperfusion (H/R) and in liver tissue during IRI in mice. The activation of miR-191 under hypoxic conditions is mediated by hypoxia-inducible factor-1α (HIF1α) binding to its promoter region. Global miR-191 KO mice were constructed by CRISPR/Cas9 system, and we found that miR-191 deficiency markedly reduces liver tissue damage, cell inflammatory responses and cell death in a mouse hepatic IRI model. Under the H/R condition, miR-191 overexpression promotes G0/G1 cell cycle arrest and cell apoptosis, but inhibition of miR-191 facilitates cell cycle progression and decreases cell death. Mechanistically, upon induction by hypoxia or ischemia, miR-191 suppresses expression of ZO-1-associated Y-box factor (ZONAB) and its downstream factor Cyclin D1, consequently resulting in cell death and tissue injury. Moreover, the effects of miR-191 on cell cycle arrest and cell apoptosis are abrogated by ZONAB overexpression, and vice versa. Taken together, our results indicate an important role of the HIF1α/miR-191/ZONAB signaling pathway in hepatic IRI and suggest miR-191 as a novel therapeutic target for the treatment of liver IRI.

Topics: Animals; Apoptosis; CCAAT-Enhancer-Binding Proteins; Cell Cycle Checkpoints; Cell Hypoxia; Cell Line, Tumor; Cyclin D1; Disease Models, Animal; DNA-Binding Proteins; Gene Knockout Techniques; Heat-Shock Proteins; HEK293 Cells; Hepatocytes; Humans; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; MicroRNAs; Reperfusion Injury; Transcription Factors; Transfection

Transplanting donor livers with severe macrosteatosis is associated with increased risk of primary non-function (PNF). The purpose of this study was to identify steatosis-driven biomarkers as a predisposition to severe liver damage and delayed recovery following ischemia reperfusion injury. Wistar rats were fed a methionine- and choline-deficient (MCD) diet for up to three weeks to achieve severe macrosteatosis (>90%). Animals underwent diet withdrawal to control chow and/or underwent ischemia reperfusion and partial hepatectomy injury (I/R-PHx) and reperfused out to 7 days on control chow. For animals with severe macrosteatosis, hepatic levels of IL-33 decreased while Cyclin D1 levels increased in the absence of NF-κB p65 phosphorylation. Animals with high levels of nuclear Cyclin D1 prior to I/R-PHx either did not survive or had persistent macrosteatosis after 7 days on control chow. Survival 7 days after I/R-PHx fell to 57% which correlated with increased Cyclin D1 and decreased liver IL-33 levels. In the absence of I/R-PHx, withdrawing the MCD diet normalized IL-33, Cyclin D1 levels, and I/R-PHx survival back to baseline. In transplanted grafts with macrosteatosis, higher Cyclin D1 mRNA expression was observed. Shifts in Cyclin D1 and IL-33 expression may identify severely macrosteatotic livers with increased failure risk if subjected to I/R injury. Clinical validation of the panel in donor grafts with macrosteatosis revealed increased Cyclin D1 expression corresponding to delayed graft function. This pre-surgical biomarker panel may identify the subset of livers with increased susceptibility to PNF.

Topics: Adult; Animals; Biomarkers; Cyclin D1; Diet; Disease Models, Animal; Disease Susceptibility; Fatty Liver; Humans; Interleukin-33; Liver; Liver Failure; Liver Transplantation; Male; Middle Aged; Rats, Wistar; Reperfusion Injury; Survival Analysis

Topics: Activating Transcription Factor 4; Acute Kidney Injury; Animals; Antigens, Differentiation, B-Lymphocyte; Apoptosis; Autophagy; Cell Hypoxia; Cell Line; Cell Proliferation; Cyclin D1; Disease Models, Animal; Eukaryotic Initiation Factor-2; Female; Genetic Predisposition to Disease; Histocompatibility Antigens Class II; Intramolecular Oxidoreductases; Kidney Tubules, Proximal; Macrophage Migration-Inhibitory Factors; Male; Mice, Inbred C57BL; Mice, Knockout; Phenotype; Regeneration; Reperfusion Injury; Secretory Leukocyte Peptidase Inhibitor; Signal Transduction; Time Factors; Transfection

The central objective was to identify the role of the PI3K-Akt activation pathway on the neuroprotection of δ-opioid receptor agonist (DADLE) against cerebral ischemia-reperfusion (I/R) injury in a rat model. Fifty-five male Sprague-Dawley (SD) rats were included to establish a middle cerebral artery occlusion (MCAO) model which were then divided into the sham, MCAO, LY294002 (MCAO+DADLE+LY294002 [inhibitor of PI3K-Akt pathway]), DADLE (MCAO+DADLE) and DMSO (MCAO+DADLE+DMSO [dimethyl sulphoxide]) groups. The cerebral infarction (CI) volume and nerve cell apoptosis was determined using TTC and TUNEL staining. Quantitative real-time polymerase chain reaction (qRT-PCR), western blotting and immunohistochemistry staining were applied for the expressions of Bad, Bax, Bcl-2 and cleaved caspase-3. The MCAO group showed higher CI volume, nerve cell apoptosis and cleaved caspase-3 expressions than the DADLE and DMSO groups, which were also higher in the LY294002 group than the DADLE group. Compared with the MCAO group, the mRNA and protein expressions of PI3K and Bcl-2, and the protein expressions of p-Akt and p-Bad were elevated, while the mRNA and protein expressions of Bax were decreased in the DADLE and DMSO groups. Decreased mRNA and protein expressions of PI3K and Bcl-2, reduced protein expressions of p-Akt and p-Bad and elevated mRNA and protein expressions of Bax exhibited in the LY294002 group than the DADLE group. These results indicate that activation of PI3K-Akt pathway promotes the neuroprotection of DADLE against cerebral I/R injury in a rat model by decreasing nerve cells apoptosis.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Brain Ischemia; Caspase 3; Cyclin D1; Infarction, Middle Cerebral Artery; Male; Neuroprotection; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Rats, Sprague-Dawley; Receptors, Opioid, delta; Reperfusion Injury; RNA, Messenger; Signal Transduction

The hypoxia-inducible factor (HIF)-1 and β-catenin protective pathways represent the two most significant cellular responses that are activated in response to acute kidney injury. We previously reported that murine mucin (Muc)1 protects kidney function and morphology in a mouse model of ischemia-reperfusion injury (IRI) by stabilizing HIF-1α, enhancing HIF-1 downstream signaling, and thereby preventing metabolic stress (Pastor-Soler et al. Muc1 is protective during kidney ischemia-reperfusion injury. Am J Physiol Renal Physiol 308: F1452-F1462, 2015). We asked if Muc1 regulates the β-catenin protective pathway during IRI as 1) β-catenin nuclear targeting is MUC1 dependent in cultured human cells, 2) β-catenin is found in coimmunoprecipitates with human MUC1 in extracts of both cultured cells and tissues, and 3) MUC1 prevents β-catenin phosphorylation by glycogen synthase kinase (GSK)3β and thereby β-catenin degradation. Using the same mouse model of IRI, we found that levels of active GSK3β were significantly lower in kidneys of control mice compared with Muc1 knockout (KO) mice. Consequently, β-catenin was significantly upregulated at 24 and 72 h of recovery and appeared in the nuclear fraction at 72 h in control mouse kidneys. Both β-catenin induction and nuclear targeting were absent in Muc1 KO mice. We also found downstream induction of β-catenin prosurvival factors (activated Akt, survivin, transcription factor T cell factor 4 (TCF4), and its downstream target cyclin D1) and repression of proapoptotic factors (p53, active Bax, and cleaved caspase-3) in control mouse kidneys that were absent or aberrant in kidneys of Muc1 KO mice. Altogether, the data clearly indicate that Muc1 protection during acute kidney injury proceeds by enhancing both the HIF-1 and β-catenin protective pathways.

Topics: Animals; Apoptosis; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; bcl-2-Associated X Protein; beta Catenin; Cyclin D1; Hypoxia-Inducible Factor 1; Inhibitor of Apoptosis Proteins; Male; Mice, Inbred C57BL; Mice, Knockout; Mucin-1; Proto-Oncogene Proteins c-akt; Reperfusion Injury; Repressor Proteins; Survivin; Transcription Factor 4; Tumor Suppressor Protein p53

MicroRNA-99a (miR-99a) has been reported to function as a tumor suppressor through regulating cell cycle and apoptosis. But its clinical significance in ischemic stroke and its function in cerebral ischemia-reperfusion (I/R) injury remained unknown. Herein transient middle cerebral artery occlusion was built on C57BL/6 mice, followed by intracerebroventricular injection of miR-99a agomir or antagomir before reperfusion for 24h. Our clinical analysis indicates that plasma miR-99a level was significantly decreased in ischemic stroke patients as compared to healthy subjects, and a significant correlation was observed between miR-99a and clinical parameters. And miR-99a overexpression mitigated I/R injury in mice, as evidenced by reduced brain infarct volume and neural apoptosis, whereas miR-99a downregulation aggravates brain injury. In vitro, miR-99a protected neuro-2a cells against hydrogen peroxide-induced oxidative stress injury, by improving cell viability, suppressing LDH release and cell apoptosis. In addition, miR-99a overexpression inhibited H2O2 induced G1/S phase transition in neuro-2a cells, accompanied by a significant decrease in cyclin D1 level and a tendency of down-regulation of CDK6. It was further proved in mice that miR-99a inhibited cyclin D1 and CDK6 expressions following cerebral I/R injury. These findings indicate that miR-99a reduces neuronal damage following cerebral I/R through regulating cell cycle progression and preventing apoptosis, suggesting that miR-99a could be used as a new therapeutic agent targeting neuronal cell cycle re-entry following stroke.

Topics: Animals; Brain Ischemia; Caspase 3; Cell Cycle; Cell Line, Tumor; Cyclin D1; Cyclin-Dependent Kinase 6; Disease Models, Animal; Gene Expression Regulation; Hydrogen Peroxide; In Situ Nick-End Labeling; L-Lactate Dehydrogenase; Male; Mice; Mice, Inbred C57BL; MicroRNAs; Neuroblastoma; Neuroprotective Agents; Oxidants; Reperfusion Injury; Statistics, Nonparametric; Transfection

The therapeutic potential of mesenchymal stem cells (MSCs) has been highlighted recently for treatment of acute or chronic liver injury, by possibly differentiating into hepatocyte-like cells, reducing inflammation, and enhancing tissue repair. Despite recent progress, exact mechanisms of action are not clearly elucidated. In this study, we attempted to explore whether and how MSCs protected hepatocytes and stimulated allograft regeneration in small-for-size liver transplantation (SFSLT).. SFSLT model was established with a 30% partial liver transplantation (30PLT) in rats. The differentiation potential and characteristics of bone marrow derived MSCs were explored in vitro. MSCs were infused transvenously immediately after graft implantation in therapy group. Expressions of apoptosis-, inflammatory-, anti-inflammatory-, and growth factor-related genes were measured by RT-PCR, activities of transcription factors AP-1 and NF-κB were analyzed by EMSA, and proliferative responses of the hepatic graft were evaluated by immunohistochemistry and western blot.. MSCs were successfully induced into hepatocyte-like cells, osteoblasts and adipocytes in vitro. MSCs therapy could not only alleviate ischemia reperfusion injury and acute inflammation to promote liver regeneration, but also profoundly improve one week survival rate. It markedly up-regulated the mRNA expressions of HGF, Bcl-2, Bcl-XL, IL-6, IL-10, IP-10, and CXCR2, however, down-regulated TNF-α. Increased activities of AP-1 and NF-κB, as well as elevated expressions of p-c-Jun, cyclin D1, and proliferating cell nuclear antigen (PCNA), were also found in MSCs therapy group.. These data suggest that MSCs therapy promotes hepatocyte proliferation and prolongs survival in SFSLT by reducing ischemia reperfusion injury and acute inflammation, and sustaining early increased expressions of c-Jun N-terminal Kinase, Cyclin D1, and NF-κB.

Topics: Animals; Cell Differentiation; Cell- and Tissue-Based Therapy; Cyclin D1; Hepatocytes; Humans; Inflammation; JNK Mitogen-Activated Protein Kinases; Liver Regeneration; Liver Transplantation; Mesenchymal Stem Cells; NF-kappa B; Rats; Reperfusion Injury

Berberine acted as a natural medicine with multiple pharmacological activities. In the present study, we examined the effect of berberine against cerebral ischemia damage from cell cycle arrest and cell survival. Oxygen-glucose deprivation of PC12 cells and primary neurons, and carotid artery ligation in mice were used as in vitro and in vivo cerebral ischemia models. We found that the effect of berberine on cell cycle arrest during ischemia was mediated by decreased p53 and cyclin D1, increased phosphorylation of Bad (higher expression of p-Bad and higher ratio of p-Bad to Bad) and decreased cleavage of caspase 3. Meanwhile, berberine activated the PI3K/Akt pathway during the reperfusion, especially the phosphor-activation of Akt, to promote the cell survival. The neural protective effect of berberine was remained in the presence of inhibitor of mitogen-activated protein/extracellular signal-regulated kinase (MEK), but was suppressed by the inhibitors of PI3K and Akt. We demonstrated that berberine induced cell cycle arrest and cell survival to resist cerebral ischemia injury.

Topics: Animals; Berberine; Brain Ischemia; Cell Cycle Checkpoints; Cell Survival; Cells, Cultured; Cyclin D1; Hippocampus; Male; Mice; Mice, Inbred ICR; Neurons; Neuroprotective Agents; PC12 Cells; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Rats; Rats, Wistar; Reperfusion Injury; RNA, Messenger; Tumor Suppressor Protein p53

Intermedin/adrenomedullin 2 (IMD/ADM2) is a newly discovered peptide closely related to adrenomedullin. We recently reported that IMD/ADM2 gene transfer could significantly reduce renal ischaemia/reperfusion injury. In this study, we evaluated the effect of IMD/ADM2 on cell proliferation and regeneration in a cultured rat renal tubular epithelial cell line (NRK-52E) of hypoxia-reoxygenation (H/R) injury.. The H/R model in NRK-52E cells consisted of hypoxia for 1 h and reoxygenation for 2 h. IMD/ADM2 was overexpressed in NRK-52E cells using the vector pcDNA3.1-IMD. Enzyme-linked immunosorbent assays were used to measure the concentration of IMD/ADM2 in the culture medium, and real-time PCR and Western blotting were used to determine mRNA and protein levels. In addition, luciferase reporter assays and electrophoretic mobility-shift assays were performed to measure cyclin D1 promoter activity and transcription factor activity.. We found that IMD/ADM2 gene transfer markedly promoted cell viability and decreased lactate dehydrogenase (LDH) activity and cell apoptosis compared with that of H/R. IMD/ADM2 increased the phosphorylation of ERK and decreased the phosphorylation of JNK and P38. Furthermore, IMD/ADM2 promoted cell cycle progression with concomitant increases in the levels of cyclin D1 and cyclin E, and these effects were blocked by the inhibition of ERK, or the agonist JNK and P38. IMD/ADM2 also increased cyclin D1 promoter activity and AP-1 DNA-binding activity.. We demonstrated that IMD/ADM2 promotes renal cell proliferation and regeneration after renal H/R injury by upregulating cyclin D1 and that this upregulation seems to be mediated by the ERK, JNK, and P38 MAPK signalling pathways.

Topics: Adrenomedullin; Animals; Apoptosis; Cell Hypoxia; Cell Line; Cell Proliferation; Cell Survival; Cyclin D1; Cyclin E; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Genes, Reporter; JNK Mitogen-Activated Protein Kinases; Kidney Diseases; Kidney Tubules; L-Lactate Dehydrogenase; MAP Kinase Signaling System; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Promoter Regions, Genetic; Rats; Regeneration; Reperfusion Injury; RNA, Messenger; Transcription Factor AP-1; Transfection; Up-Regulation

Glycogen synthase kinase (GSK)-3beta/beta-catenin signaling regulates ischemia-reperfusion (I/R)-induced apoptosis and proliferation, and inhibition of GSK-3beta has beneficial effects on I/R injury in the heart and the central nervous system. However, the role of this signaling in hepatic I/R injury remains unclear. The present study aimed to investigate the effects and mechanism of GSK-3beta/beta-catenin signaling in hepatic I/R injury.. Male C57BL/6 mice (weighing 22-25 g) were pretreated with either SB216763, an inhibitor of GSK-3beta, or vehicle. These mice were subjected to partial hepatic I/R. Blood was collected for test of alanine aminotransferase (ALT), and liver specimen for assays of phosphorylation at the Ser9 residue of GSK-3beta, GSK-3beta activity, axin 2 and the anti-apoptotic factors Bcl-2 and survivin, as well as the proliferative factors cyclin D1 and proliferating cell nuclear antigen, and apoptotic index (TUNEL). Real-time PCR, Western blotting and immunohistochemical staining were used.. SB216763 increased phospho-GSK-3beta levels and suppressed GSK-3beta activity (1880+/-229 vs 3280+/-272 cpm, P<0.01). ALT peaked at 6 hours after reperfusion. Compared with control, SB216763 decreased ALT after 6 hours of reperfusion (4451+/-424 vs 7868+/-845 IU/L, P<0.01), and alleviated hepatocyte necrosis and vacuolization. GSK-3beta inhibition led to the accumulation of beta-catenin in the cytosol (0.40+/-0.05 vs 1.31+/-0.11, P<0.05) and nucleus (0.62+/-0.14 vs 1.73+/-0.12, P<0.05), beta-catenin further upregulated the expression of axin 2. Upregulation of GSK-3beta/beta-catenin signaling increased Bcl-2, survivin and cyclin D1. Serological and histological analyses showed that SB216763 alleviated hepatic I/R-induced injury by reducing apoptosis (1.4+/-0.2% vs 3.6+/-0.4%, P<0.05) and enhanced liver proliferation (56+/-8% vs 19+/-4%, P<0.05).. Inhibition of GSK-3beta ameliorates hepatic I/R injury through the GSK-3beta/beta-catenin signaling pathway.

Topics: Alanine Transaminase; Animals; Apoptosis; Axin Protein; beta Catenin; Blotting, Western; Cell Proliferation; Cyclin D1; Disease Models, Animal; Gene Expression Regulation; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Immunohistochemistry; Indoles; Inhibitor of Apoptosis Proteins; Liver; Liver Regeneration; Male; Maleimides; Mice; Mice, Inbred C57BL; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Real-Time Polymerase Chain Reaction; Reperfusion Injury; Repressor Proteins; Signal Transduction; Survivin; Time Factors

Interleukin (IL)-33 is a recently identified member of the IL-1 family that binds to the receptor, ST2L. In the current study, we sought to determine whether IL-33 is an important regulator in the hepatic response to ischemia/reperfusion (I/R). Male C57BL/6 mice were subjected to 90 minutes of partial hepatic ischemia, followed by up to 8 hours of reperfusion. Some mice received recombinant IL-33 (IL-33) intraperitoneally (IP) before surgery or anti-ST2 antibody IP at the time of reperfusion. Primary hepatocytes and Kupffer cells were isolated and treated with IL-33 to assess the effects of IL-33 on inflammatory cytokine production. Primary hepatocytes were treated with IL-33 to assess the effects of IL-33 on mediators of cell survival in hepatocytes. IL-33 protein expression increased within 4 hours after reperfusion and remained elevated for up to 8 hours. ST2L protein expression was detected in healthy liver and was up-regulated within 1 hour and peaked at 4 hours after I/R. ST2L was primarily expressed by hepatocytes, with little to no expression by Kupffer cells. IL-33 significantly reduced hepatocellular injury and liver neutrophil accumulation at 1 and 8 hours after reperfusion. In addition, IL-33 treatment increased liver activation of nuclear factor kappa light-chain enhancer of activated B cells (NF-κB), p38 mitogen-activated protein kinase (MAPK), cyclin D1, and B-cell lymphoma 2 (Bcl-2), but reduced serum levels of CXC chemokines. In vitro experiments demonstrated that IL-33 significantly reduced hepatocyte cell death as a result of increased NF-κB activation and Bcl-2 expression in hepatocytes.. The data suggest that IL-33 is an important endogenous regulator of hepatic I/R injury. It appears that IL-33 has direct protective effects on hepatocytes, associated with the activation of NF-κB, p38 MAPK, cyclin D1, and Bcl-2 that limits liver injury and reduces the stimulus for inflammation.

Topics: Analysis of Variance; Animals; Blotting, Western; Cells, Cultured; Cyclin D1; Cytokines; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Hepatocytes; Interleukin-33; Interleukins; Kupffer Cells; Male; Mice; Mice, Inbred C57BL; NF-kappa B; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Random Allocation; Receptors, Interleukin-1; Reperfusion; Reperfusion Injury

To investigate the effect of pretreatment with ulinastatin on liver regeneration and TNF-α/IL-6/STAT-3 signal pathway in rats after 70% hepatectomy combined with ischemia-reperfusion injury.. A total of 120 normal male SD rats weighing 230-280 g were randomized into 3 groups (n=40), namely simple partial hepatectomy (PH) group, partial hepatectomy with ischemia-reperfusion (PHIR) group, and ulinastatin group. All the rats received resection of the left and middle liver lobes. In PHIR group, the remnant right lobes were subjected to blood flow occlusion for 30 min; in UTI group, the rats were given 50 000 U/kg UTI intravenously prior to the occlusion, and in PH group, the blood flow was not occluded. At 1, 6, 12, 24, and 48 after the reperfusion, the remnant liver tissues were examined for regenerated liver weight, PCNA staining, TNF-α and IL-6, STAT-3, cyclin D1, and Cdk4 expressions.. The regenerated liver weight and PCNA positivity rates were significantly higher in ulinastatin group than in PHIR group at 24 h and 48 h after the reperfusion (P<0.05). In ulinastatin group, the levels of TNF-α and IL-6 were significantly lower, and IL-6 level and the expressions of STAT-3, cyclin D1, and Cdk4 mRNA and cyclin D1 and Cdk4 proteins were significantly higher in ulinastatin group than in PHIR group at 24 h and 48 h (P<0.05).. Ulinastatin can promote liver regeneration after major hepatectomy and ischemia-reperfusion injury, and the effect is possibly related with activation of IL-6/STAT-3 signal pathway, which promotes the synthesis of cyclin Dl-Cdk4 complex and hepatocyte proliferation.

Topics: Animals; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase 4; Glycoproteins; Hepatectomy; Hepatocytes; Interleukin-6; Liver; Liver Regeneration; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Signal Transduction; STAT3 Transcription Factor; Tumor Necrosis Factor-alpha

To investigate hepatic regenerative response and associated mechanisms in different-size liver grafts in the rat.. Rat models of different-size-graft liver transplantation (whole, 50%-size, or 30%-size) were established, with a sham operation group serving as a control. Portal pressure, graft injury, interleukin 6 (IL-6), signal transducer and activator of transcription (Stat3), mitogen-activated protein kinase (MAPK), cyclin D1, and proliferating cell nuclear antigen (PCNA) were all assessed.. The portal pressure was significantly higher and hepatic injury more severe in the smaller sized groups than in the whole graft group, especially in the 30%-size grafts. Hepatic IL-6 and tumor necrosis factor-alpha (TNF-alpha) levels in the two smaller sized groups were significantly higher than in the whole graft group, while IL-6 levels appeared to be negatively associated with graft sizes. Downstream markers of IL-6, Stat3 and MAPK phosphorylation, cyclin D1, and PCNA expression were also markedly increased in the small-sized grafts compared with the whole grafts, and appeared to positively correlate with early measurements of portal pressure and subsequent hepatic injury.. Vigorous hepatic regeneration in small-for-size liver grafts may be associated with highly activated IL-6/Stat3 and MAPK signaling, which may in turn correlate with graft size, portal pressure, and hepatic injury.

Topics: Animals; Cell Cycle; Cell Division; Cyclin D1; Hemodynamics; Hypertension, Portal; Interleukin-6; Liver; Liver Regeneration; Liver Transplantation; Male; Mitogen-Activated Protein Kinase Kinases; Portal Pressure; Portal Vein; Proliferating Cell Nuclear Antigen; Rats; Rats, Inbred Lew; Reperfusion Injury; STAT3 Transcription Factor

Cholangiocyte proliferation is necessary for biliary recovery from cold ischemia and reperfusion injury (CIRI), but there are few studies on its intracellular mechanism. In this process, the role of rapamycin, a new immunosuppressant used in liver transplantation, is still unknown. In order to determine whether rapamycin can depress cholangiocyte regeneration by inhibiting signal transducer and activator of transcription 3 (STAT3) activation, rapamycin (0.05 mg/kg) was administered to rats for 3 days before orthotopic liver transplantation. The results indicated that cholangiocytes responded to extended cold preservation (12 hours) with severe bile duct injures, marked activation of the interleukin-6 (IL-6)/STAT3 signal pathway, and increased expression of cyclin D1 until 7 days after transplantation, and this was followed by compensatory cholangiocyte regeneration. However, rapamycin treatment inhibited STAT3 activation and resulted in decreased cholangiocyte proliferation and delayed biliary recovery after liver transplantation. On the other hand, rapamycin showed no effect on the expression of IL-6. We conclude that the IL-6/STAT3 signal pathway is involved in initiating cholangiocytes to regenerate and repair CIRI. Rapamycin represses cholangiocyte regeneration by inhibiting STAT3 activation, which might have a negative effect on the healing and recovery of bile ducts in grafts with extended cold preservation. Insights gained from this study will be helpful in designing therapy using rapamycin in clinical patients after liver transplantation.

Topics: Animals; Bile Ducts, Intrahepatic; Cell Division; Cryopreservation; Cyclin D1; Disease Models, Animal; Graft Rejection; Immunosuppressive Agents; Interleukin-6; Liver Regeneration; Liver Transplantation; Male; Phosphorylation; Rats; Rats, Wistar; Reperfusion Injury; Sirolimus; STAT3 Transcription Factor

Liver resection includes temporal vascular inflow occlusion resulting in ischemia/reperfusion injury in the remnant liver. Here, we developed a rat model of selective lobe occlusion to isolate reperfusion stress from ischemia and to analyze its effect on liver regeneration.. Left lateral and median lobes of liver were either mobilized or subjected twice for 10min to ischemia followed by 5min reperfusion prior to resection while the regenerative lobes were only subjected to reperfusion.. Although intermittent reperfusion stress induced higher levels of serum transaminases, analysis of cell cycle regulators revealed accelerated regenerative response compared to standard partial hepatectomy. The G0/G1 transition occurred before tissue resection, as evidenced by c-fos, junB, and IL-6 induction. Following hepatectomy, Cyclin D1 up-regulation, G1/S transition, and cell division occurred earlier than normal. Unexpectedly, liver mobilization, a component of the clamping procedure, also resulted in earlier G1/S transition. The shortened G1-phase was driven by the c-Jun N-terminal Kinase pathway and was associated with an oxidative stress response as evidenced by the expression of inducible nitric oxide synthase.. Intermittent selective clamping of lobes to be resected induced reperfusion stress on remnant liver that was beneficial for liver regeneration, suggesting this procedure could be applied in clinical practice.

Topics: Animals; Cell Division; Cyclin D1; G1 Phase; Gene Expression; Heme Oxygenase-1; Hepatectomy; Hepatocytes; Interleukin-6; JNK Mitogen-Activated Protein Kinases; Liver Regeneration; Male; Nitric Oxide Synthase Type II; Proto-Oncogene Proteins c-fos; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Resting Phase, Cell Cycle; S Phase; Signal Transduction; STAT3 Transcription Factor; Stress, Physiological; Superoxide Dismutase; Surgical Instruments

To investigate the effects of ischaemic preconditioning (IP) on residual liver regeneration after major hepatectomy without portal blood bypass in rats, and to verify whether it can protect the residual liver from ischaemia reperfusion (IR) injury.. Ninety rats were randomized into three groups: Group PH, rats were subjected to 70% hepatectomy alone; Group IR, rats were subjected to 30 minutes of total hepatic ischaemia, and 70% hepatectomy was performed just before reperfusion; Group IP, rats were pretreated with IP (5/10 minutes). During the preoperative period and at 0.5, 6, 12, 24 and 48 hours after the operation, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were measured using an autoanalyser. Serum hyaluronic acid (HA) was measured by radioimmunoassay. Regenerated liver weight (RLW) of the rats was measured and the expressions of Ki-67 and cyclin D1 were determined by immunohistochemistry in remnant liver tissue.. There were no significant differences in serum AST and ALT levels in all the groups before the operation. After partial hepatectomy, AST and ALT levels increased rapidly. From 0.5 to 24 hours after operation, serum AST and ALT levels were significantly higher in IP group rats than in PH and IR rats (p < 0.05). There were no significant differences in serum HA levels in all the groups before the operation. After partial hepatectomy, HA levels increased rapidly, reaching peak values at 12 hours. In the early stage (during 12 hours) after the operation, HA level was significantly higher in IP rats than in PH and IR rats (p < 0.05). The RLW of the rats rapidly increased after partial hepatectomy, and significantly decreased in IP rats compared with PH and IR rats (p < 0.05). Cyclin D1 and Ki-67 expression in all groups before the operation were low and were not significantly different. After partial hepatectomy, they rapidly increased. The expression of Ki-67 and cyclin D1 reached a peak at 24 hours after the operation in PH rats, and they were significantly higher compared with IR and IP rats (p < 0.05). In groups IR and IP, the expression of cyclin D1 and Ki-67 reached peak values at 48 hours. A significant decrease (p < 0.05) was observed after 24 and 48 hours of reperfusion in group IP compared with groups PH and IR.. IP impairs residual liver regeneration after major hepatectomy without portal blood bypass in rats, and protection from IR injury disappears. IP-induced hyperperfusion may be the cause of reduced liver regeneration.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Cyclin D1; Female; Hepatectomy; Hyaluronic Acid; Ischemic Preconditioning; Ki-67 Antigen; Liver Regeneration; Models, Animal; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Time Factors

To observe the effect of ischemic preconditioning on cyclinD1 expression in rat liver cells during early ischemic reperfusion.. Fifty-four SD rats were randomly divided into ischemic preconditioning group (IP), ischemia/reperfusion group (IR) and sham operation group (SO). The IP and IR groups were further divided into four sub-groups (n = 6). Sham operation group (SO) served as the control group (n = 6). A model of partial liver ischemia/reperfusion was used, in which rats were subjected to liver ischemia for 60 min prior to reperfusion. The animals in the IP group underwent ischemic preconditioning twice for 5 min each time prior to the ischemia/reperfusion challenge. After 0, 1, 2, and 4 h of reperfusion, serum and liver tissue in each group were collected to detect the level of serum ALT, liver histopathology and expression of cyclinD1 mRNA and protein. Flow cytometry was used to detect cell cycle as the quantity indicator of cell regeneration.. Compared with IR group, IP group showed a significantly lower ALT level in 1 h to 4 h sub-groups (P < 0.05). Proliferation index (PI) indicated by the S-phase and G2/M-phase ratio [(S+G2/M)/(G0/G1+S+G2/M)] was significantly increased in IP group at 0 and 1 h (26.44 +/- 7.60% vs 18.56 +/- 6.40%, 41.87 +/- 7.27% vs 20.25 +/- 6.70%, P < 0.05). Meanwhile, cyclinD1 protein expression could be detected in IP group. But in IR group, cyclinD1 protein expression occurred 2 h after reperfusion. The expression of cyclinD1 mRNA increased significantly in IP group at 0 and 1 h (0.568 +/- 0.112 vs 0.274 +/- 0.069, 0.762 +/- 0.164 vs 0.348 +/- 0.093, P < 0.05).. Ischemic preconditioning can protect liver cells against ischemia/reperfusion injury, which may be related to cell proliferation and expression of cyclinD1 during early ischemic reperfusion.

Topics: Alanine Transaminase; Animals; Cell Cycle; Cell Proliferation; Cyclin D1; Flow Cytometry; Gene Expression Regulation; Ischemia; Ischemic Preconditioning; Liver; Liver Regeneration; Male; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

To investigate the effect and possible mechanism of ulinastatin on renal ischemia-reperfusion injury in rats.. Male Sprague-Dawley rats were subjected to 45-min bilateral renal ischemia, treated with intravenously 12,500 U ulinastatin at 30 min prior to ischemia and at the beginning of reperfusion, compared with a nontreated group without ulinastatin and a sham-operation group without bilateral renal ischemia. After 0 h, 2 h, 6 h, 12 h, and 24 h of reperfusion, serum creatinine and blood urea nitrogen were measured for the assessment of renal function, renal sections were used for histologic grading of renal injury, for immunohistochemical localization of Bcl-2 and heat shock protein 70. Renal ultrastructure was observed through a transmission electron microscope.. Ulinastatin significantly reduced the increase in blood urea nitrogen and creatinine produced by renal ischemia-reperfusion, suggesting an improvement in renal function. Ulinastatin reduced the histologic evidence of renal damage associated with ischemia-reperfusion and accompanied with an up-regulation in the expression of Bcl-2 protein, but it had no significant effect on the expression of HSP 70. Ulinastatin also significantly reduced kidney ultrastructure damage caused by renal ischemia-reperfusion.. The protease inhibitor, ulinastatin, reduced the renal dysfunction and injury associated with ischemia-reperfusion of the kidney. The protective effect of ulinastatin might be associated with the up-regulation of Bcl-2 expression and the effect on membrane fragility.

Topics: Animals; Blood Urea Nitrogen; Creatinine; Cyclin D1; Glycoproteins; HSP70 Heat-Shock Proteins; Ischemia; Kidney; Male; Protective Agents; Rats; Rats, Sprague-Dawley; Reperfusion Injury

If temporary inflow occlusion is required during liver resection, the postoperative course might be complicated by ischaemia-reperfusion injury. Steroids protect against ischaemia-reperfusion injury; however, due to its anti-proliferative character concerns exist on its use on liver regeneration after resection. We investigated the effects of methylprednisolone on hepatocyte proliferation after partial hepatectomy with temporary inflow occlusion.. Prior to surgery, one group of Wistar rats received methylprednisolone, while a second group served as non-treated controls. Ischaemia-reperfusion injury was indicated by AST, ALT, and GLDH at 6 h after surgery. Immunohistochemistry tools were used to determine the mitotic index and Ki-67 expression, while cyclin D1 expression characterized the proliferative activity on days 1, 4, 7, and 10.. The post-ischaemic liver enzyme release had significantly decreased in the methylprednisolone group, while expression of cyclin D1, percentage of Ki-67-positive cells, and mitotic cell index were comparable in both groups. Similar results were found for bilirubin and albumin and for weight of proliferating liver.. Although steroid administration significantly reduced ischaemia-reperfusion-associated tissue injury, it has no apparent effects on hepatic regeneration. Thus, steroids could be recommended if a temporary liver ischaemia is required during surgery, in order to reduce complications caused by severe ischaemia-related organ dysfunction.

Topics: Animals; Anti-Inflammatory Agents; Blotting, Western; Cyclin D1; Data Interpretation, Statistical; Hepatectomy; Immunohistochemistry; Injections, Intravenous; Ki-67 Antigen; Liver Regeneration; Male; Methylprednisolone; Postoperative Period; Preoperative Care; Rats; Rats, Wistar; Reperfusion Injury; Time Factors

Tumor necrosis factor alpha (TNF-alpha) is implicated in the pathogenesis of hepatic ischemia reperfusion injury but can also prime hepatocytes to enter the cell cycle. Ischemic preconditioning protects against ischemia-reperfusion (IR) liver injury and is associated with activation of nuclear factor kappaB (NF-kappaB) and cell cycle entry. We examined the pattern of TNF-alpha release during hepatic IR in the presence or absence of ischemic preconditioning, and we tested whether a single low-dose injection of TNF could mimic the biologic effects of ischemic preconditioning. In naïve mice, hepatic and plasma levels of TNF-alpha rose during hepatic ischemia, reaching high levels after 90 minutes; values remained elevated during reperfusion until 44 hours. Following the ischemic preconditioning stimulus, there was an early rise in hepatic and serum TNF-alpha levels, but, during a second prolonged ischemic interval peak, TNF-alpha values were lower than in naïve mice and declined to negligible levels by 2 hours reperfusion. An injection with 1 microg or 5 microg/kg body weight TNF-alpha 30 minutes prior to hepatic IR substantially reduced liver injury determined by liver histology and serum alanine aminotransferase (ALT) levels. As in ischemic preconditioning, TNF-alpha pretreatment activated NF-kappaB DNA binding, STAT3, cyclin D1, cyclin-dependent kinase 4 (cdk4) expression, and cell cycle entry, determined by proliferating cell nuclear antigen (PCNA) staining of hepatocyte nuclei. In conclusion, the hepatoprotective effects of "preconditioning" can be simulated by TNF-alpha injection, which has identical downstream effects on cell cycle entry. We propose that transient increases in TNF-alpha levels may substitute for, as well as, mediate the hepatoprotective effects of ischemic preconditioning against hepatic IR injury.

Topics: Animals; Antineoplastic Agents; Cell Cycle; Cell Nucleus; Cyclin D1; DNA-Binding Proteins; Dose-Response Relationship, Drug; Enzyme Activation; Female; I-kappa B Proteins; Ischemic Preconditioning; JNK Mitogen-Activated Protein Kinases; Liver; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Reperfusion Injury; Signal Transduction; STAT3 Transcription Factor; Trans-Activators; Tumor Necrosis Factor-alpha

A brief period of hepatic ischemia protects the liver against subsequent ischemia-reperfusion (IR) injury, but the mechanism of such preconditioning is poorly understood. We examined whether preconditioning activated nuclear factor kappa B (NF-kappaB), the stress-activated protein kinases (SAPK), c-Jun N-terminal kinase-1 (JNK-1) and p38, and entry into the cell cycle. We used a murine model of partial hepatic ischemia. Preconditioning was performed by clamping the vasculature for 2 to 20 minutes, and allowing reperfusion for 10 minutes before 90-minute ischemia or IR. As assessed by serum alanine aminotransferase (ALT) levels and liver histology, preconditioning periods of 5 and 10 minutes were highly protective against IR injury, whereas 2-, 15-, and 20-minute intervals were ineffective. Preconditioning was associated with entry of hepatocytes into the cell cycle within 2 hours of subsequent IR, as indicated by proliferating cell nuclear antigen (PCNA) nuclear staining, induction of cyclin D1 and numerous mitotic figures; in the absence of preconditioning, such changes were not seen until 24 hours. Preconditioning increased nuclear binding of NF-kappaB within 30 minutes of the subsequent ischemic interval, paralleled by degradation of inhibitory (binding) protein for NF-kappaB (IkappaBalpha). Ischemic preconditioning also activated p38 kinase and JNK-1, which are known to converge on cyclin D1 regulation. The protective effect of the preconditioning regimen was more closely associated with p38 kinase than JNK-1 activation. In conclusion, the hepatoprotective effects of ischemic preconditioning are associated with activation of NF-kappaB and SAPKs that are associated with entry of hepatocytes into the cell cycle, a critical biological effect that favors survival of the liver against ischemic and IR injury.

Topics: Animals; Cell Cycle; Cell Nucleus; Cyclin D1; Cytosol; Female; Hepatocytes; Ischemic Preconditioning; Liver; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinase 8; Mitogen-Activated Protein Kinases; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Proliferating Cell Nuclear Antigen; Reperfusion Injury

Cyclin-dependent kinases (CDKs) are commonly known to regulate cell proliferation. However, previous reports suggest that in cultured postmitotic neurons, activation of CDKs is a signal for death rather than cell division. We determined whether CDK activation occurs in mature adult neurons during focal stroke in vivo and whether this signal was required for neuronal death after reperfusion injury. Cdk4/cyclin D1 levels and phosphorylation of its substrate retinoblastoma protein (pRb) increase after stroke. Deregulated levels of E2F1, a transcription factor regulated by pRb, are also observed. Administration of a CDK inhibitor blocks pRb phosphorylation and the increase in E2F1 levels and dramatically reduces neuronal death by 80%. These results indicate that CDKs are an important therapeutic target for the treatment of reperfusion injury after ischemia.

Topics: Animals; Apoptosis; Brain; Carrier Proteins; Cell Cycle Proteins; Cerebrovascular Circulation; Cyclin D1; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinases; DNA-Binding Proteins; E2F Transcription Factors; E2F1 Transcription Factor; Enzyme Inhibitors; Flavonoids; Ischemic Attack, Transient; Male; Neurons; Piperidines; Proto-Oncogene Proteins; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Retinoblastoma-Binding Protein 1; Transcription Factor DP1; Transcription Factors

To investigate whether lipid peroxides play a role in retinal cell death due to ischemia-reperfusion injury, whether recombinant human thioredoxin (rhTRX) treatment reduces production of lipid peroxides of the retina, and whether such treatment reduces the number of cells expressing c-Jun and cyclin D1.. Retinal ischemia was induced in rats by increasing the intraocular pressure to 110 mm Hg for 60 minutes. After reperfusion, immunohistochemical staining for lipid peroxide, peroxynitrite, c-Jun, and cyclin D1 and propidium iodide (PI) staining were performed on retinal sections from animals treated intravenously with and without rhTRX, a free radical scavenger. Quantitative analyses of PI-, c-Jun-, and cyclin D1-positive cells were performed after the ischemic insult. Concentration of lipid peroxides in the retina was determined by the thiobarbituric acid assay.. Specific immunostaining for lipid peroxides was seen in the ganglion cell layer at 6 hours after reperfusion, in the inner nuclear layer at 12 hours, and in the outer nuclear layer at 48 hours. Time course studies for PI-positive cells in the three nuclear layers coincided with those of specific immunostaining for lipid peroxides. The specific immunostaining was weakened by pre- and posttreatment with 0.5 mg of rhTRX. The number of PI-, c-Jun-, and cyclin D1-positive cells and the concentration of lipid peroxides were significantly decreased by treatment with rhTRX compared with those of vehicle-treated control rats (P: < 0. 01).. Lipid peroxides formed by free radicals may play a role in neuronal cell death in retinal ischemia-reperfusion injury.

Topics: Aldehydes; Animals; Cell Death; Cyclin D1; Fluorescent Antibody Technique, Indirect; Free Radical Scavengers; Lipid Peroxidation; Lipid Peroxides; Male; Nitrates; Propidium; Proto-Oncogene Proteins c-jun; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Reperfusion Injury; Retina; Retinal Diseases; Thiobarbituric Acid Reactive Substances; Thioredoxins

To investigate whether cell cycle-related genes play a role in neuronal cell death in retinal ischemia-reperfusion injury.. Retinal ischemia-reperfusion injury was induced in rats by a ligation method and also by increasing the intraocular pressure. After 1 hour-of ischemia, cell death in the retina was studied using the TdT-dUTP terminal nick-end labeling (TUNEL) method, propidium iodide (PI) staining, DNA ladder formation, and ultrastructural studies. Immunohistochemical studies using antibodies against cell cycle-related genes were conducted. Changes in expression of cyclin D1 mRNA were quantitated using competitive quantitative polymerase chain reaction.. At 3 hours after reperfusion, cells in the ganglion cell layer were the first to die, followed by those in the inner nuclear layer (at 6 hours) and outer nuclear layer (at 9 hours). Ultrastructural studies revealed condensed nuclei and relatively preserved mitochondria; DNA ladder formation was also detected. Immunostaining was positive for the cell cycle-related gene products c-Jun, cyclin B1, and cyclin D1. The time course of TUNEL-positive cells and that of cells positive for c-Jun or cyclin D1 in the inner nuclear layer was similar. A double-labeling study, using PI or TUNEL, and immunohistochemical analysis revealed that dying cells expressed c-Jun and cyclin D1, whereas cyclin B1 expression was observed in Müller cells. Quantitation of cyclin D1 mRNA revealed an approximate 4-fold increase at 24 hours after reperfusion.. Aberrant expression of cell cycle-related genes may play an important role in the cell death that accompanies retinal ischemia-reperfusion injury.

Topics: Animals; Apoptosis; Cell Cycle; Cyclin B; Cyclin B1; Cyclin D1; DNA; DNA Fragmentation; DNA Primers; Electrophoresis, Agar Gel; Fluorescent Antibody Technique, Indirect; Gene Expression; Immunoenzyme Techniques; Male; Neurons, Afferent; Polymerase Chain Reaction; Proto-Oncogene Proteins c-jun; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Retina; Retinal Vessels; RNA, Messenger