thymosin and Reperfusion-Injury

The aim of the present study was to investigate the protective effects of thymosin β4 (Tβ4) on neuronal apoptosis in rat middle cerebral artery occlusion ischemia/reperfusion (MCAO I/R) injury, and determine the mechanisms involved in this process. Forty‑eight adult male Sprague‑Dawley rats were randomly divided into three groups (n=16 per group): A sham control group, an ischemia/reperfusion group (I/R group), and a Tβ4 group. The focal cerebral I/R model was established by blocking the right MCA for 2 h, followed by reperfusion for 24 h. The Zea‑Longa method was used to assess neurological deficits. Cerebral infarct volume was assessed using 2,3,5‑triphenyltetrazolium chloride staining, and pathological changes were observed via hematoxylin and eosin staining. The terminal dexynucleotidyl transferase (TdT)‑mediated dUTP nick end labeling (TUNEL) assay was used to detect apoptosis. The expression of glucose‑regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and caspase‑12 (CASP12) protein was assessed using immunohistochemistry and western blotting 24 h after reperfusion. Infarct volume and neuronal damage in the I/R and Tβ4 groups were significantly greater than those observed in the sham group. The Zea‑Longa score, neuronal apoptosis, and expression of GRP78, CHOP, and CASP12 in the I/R and Tβ4 groups were significantly higher than those reported in the sham group. However, the Longa score and neuronal apoptosis were lower in the Tβ4 group compared to the I/R group. The expression of GRP78 was significantly increased, whereas that of CHOP and CASP12 was significantly decreased in the Tβ4 group compared to the I/R group. The present data revealed that Tβ4 can inhibit neuronal apoptosis by upregulating GRP78 and downregulating CHOP and CASP12, thereby reducing cerebral I/R injury.

Topics: Animals; Apoptosis; Brain Ischemia; Disease Models, Animal; Immunohistochemistry; Male; Neurons; Rats; Reperfusion Injury; Thymosin

Prothymosin alpha (ProTα) has robustness roles against brain and retinal ischemia or serum-starvation stress. In the ProTα sequence, the active core 30-amino acid peptide/P30 (a.a.49-78) is necessary for the original neuroprotective actions against ischemia. Moreover, the 9-amino acid peptide sequence/P9 (a.a.52-60) in P30 still shows neuroprotective activity against brain and retinal ischemia, though P9 is less potent than P30. As the previous structure-activity relationship study for ProTα may not be enough, the possibility still exists that any sequence smaller than P9 retains potent neuroprotective activity. When different P9- and P30-related peptides were intravitreally injected 24h after retinal ischemia in mice, the 6-amino acid peptide/P6 (NEVDEE, a.a.51-56) showed potent protective effects against ischemia-induced retinal functional deficits, which are equipotent to the level of P30 peptide in electroretinography (ERG) and histological damage in Hematoxylin and Eosin (HE) staining. Further studies using ERG and HE staining suggested that intravitreal or intravenous (i.v.) injection with modified P6 peptide/P6Q (NEVDQE) potently inhibited retinal ischemia-induced functional and histological damage. In an immunohistochemical analysis, the ischemia-induced loss of retinal ganglion, bipolar, amacrine and photoreceptor cells were inhibited by a systemic administration with P6Q peptide 24h after the ischemic stress. In addition, systemic post-treatment with P6Q peptide significantly inhibited retinal ischemia-induced microglia and astrocyte activation in terms of increased ionized calcium-binding adaptor molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) intensity, respectively, as well as their morphological changes, increased number and migration. Thus, this study demonstrates the therapeutic significance of modified P6 peptide P6Q (NEVDQE) derived from 6-amino acid peptide (P6) in ProTα against ischemic damage.

Topics: Animals; Electroretinography; Ischemia; Male; Mice, Inbred C57BL; Microglia; Neuroprotective Agents; Protein Precursors; Reperfusion Injury; Retinal Diseases; Thymosin

Random skin flaps can be used throughout the hands and fingers. Thymosin β4 can increase blood flow and reduce ischemia-reperfusion injury; the study was undertaken to investigate the effect of thymosin β4 on the survival of random skin flaps.. A total of 45 male Sprague-Dawley rats were used and subjected to a random-pattern skin flaps operation. Rats were randomly divided into three groups: a control group (group A: intraperitoneal injection of saline, 5 mg/kg/d) and two treatment groups (group B: intraperitoneal injection of thymosin β4, a single 5 mg/kg dose per day) and (group C: intraperitoneal injection of thymosin β4, 5 mg/kg dose twice per day). The flap surviving area was measured after 7 days, and tissue samples were stained with hematoxylin and eosin. Vascular endothelial growth factor (VEGF) expression was determined using immunohistochemical methods. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were examined with kits.. Thymosin β4 significantly reduced the necrotic area in the treatment groups after 7 days compared with the control group, and the rats receiving thymosin β4 5 mg/kg twice per day had the highest survival rate. VEGF expression and SOD activity markedly increased in the treatment groups compared with the control group, whereas MDA levels were lower in the treatment groups than in the control group.. Thymosin β4 may have a dose-dependent effect to promote the survival of random skin flaps.

Topics: Animals; Dose-Response Relationship, Drug; Immunohistochemistry; Injections, Intraperitoneal; Male; Microfilament Proteins; Microvessels; Rats, Sprague-Dawley; Regional Blood Flow; Reperfusion Injury; Superoxide Dismutase; Surgical Flaps; Thymosin; Vascular Endothelial Growth Factor A

Our aim was to explore the therapeutic effects of peripheral blood-derived endothelial progenitor cells (PB-EPC) in cardiac ischemia-reperfusion infarction models in rats and in in vitro culture systems.. Rat models of ischemia reperfusion and myocardial infarction were developed using male, Sprague-Dawley rats. Cardiomyocyte and endothelial cell cultures were also established. Therapeutic effects of PB-EPCs were examined in vivo and in vitro in both models. Rats underwent either cardiac ischemia-reperfusion (n = 40) or infarction (n = 56) surgeries and were transplanted with genetically modified EPCs. Treatment efficacy in the ischemia-reperfusion group was measured by infarct size, myocardial contraction velocity, and myeloperoxidase activity after transplantation. Cardiomyocyte survival and endothelial cell apoptosis were investigated in vitro. Vascular growth-associated protein expression and cardiac function were evaluated in the myocardial infarction group by western blot and echocardiography, respectively.. Infarct size and myeloperoxidase activity were significantly decreased in the ischemia-reperfusion group, whereas myocardial contractility was significantly increased in the EPC and Tβ4 groups compared with that in the control group. In contrast, no differences were found between EPC + shRNA Tβ4 and control groups. Rates of cardiomyocyte survival and endothelial cell apoptosis were significantly higher and lower, respectively, in the EPC and Tβ4 groups than in the control group, whereas no differences were found between the EPC + shRNA Tβ4 and control group. Four weeks after myocardial infarction, cardiac function was significantly better in the EPC group than in the control group. Expressions of PDGF, VEGF, and Flk-1 were significantly higher in EPC group than in control group.. Study findings suggest that PB-EPCs are able to protect cardiomyocytes from ischemia-reperfusion or infarction-induced damage via a Tβ4-mediated mechanism. EPCs may also provide protection through increased expression of proteins involved in mediating vascular growth. Autologous peripheral-blood-derived EPCs are readily available for efficient therapeutic use without the concerns of graft rejection.

Topics: Analysis of Variance; Animals; Apoptosis; Blotting, Western; Cell Survival; Disease Models, Animal; Endothelial Cells; Hematopoietic Stem Cells; Hemodynamics; Infarction; Intercellular Signaling Peptides and Proteins; Male; Myocardial Contraction; Myocytes, Cardiac; Peroxidase; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Stem Cell Transplantation; Thymosin

Prothymosin-alpha (ProTalpha) causes a switch in cell death mode from necrosis to neurotrophin-reversible apoptosis in primary cultured cortical neurons. In the present study, post-ischemic administration (3 or 24 h, intravenously) of recombinant mouse ProTalpha without neurotrophins completely prevented ischemia-induced retinal damage accompanying necrosis and apoptosis, as well as dysfunction assessed by electroretinogram. Treatments with anti-erythropoietin (EPO) or brain-derived neurotrophic factor (BDNF) immunoglobulin G (IgG) reversed ProTalpha-induced inhibition of apoptosis. ProTalpha upregulated retinal EPO and BDNF levels in the presence of ischemia. Moreover, intravitreous administration of anti-ProTalpha IgG or an antisense oligodeoxynucleotide for ProTalpha accelerated ischemia-induced retinal damage. We also observed that ischemia treatment caused a depletion of ProTalpha from retinal cells. Altogether, these results suggest that the systemic administration of ProTalpha switches ischemia-induced necrosis to apoptosis, which in turn is inhibited by neurotrophic factors upregulated by ProTalpha and ischemia. ProTalpha released upon ischemic stress was found to have a defensive role in retinal ischemia.

Topics: Animals; Antibodies; Apoptosis; Brain-Derived Neurotrophic Factor; Erythropoietin; Ischemia; Male; Mice; Necrosis; Protein Precursors; Reperfusion Injury; Retina; Retinal Vessels; Thymosin