hyperoside and Disease-Models--Animal

An inclusion complex formation with cyclodextrin is a promising method to improve the bioavailability of water-insoluble drugs. The pharmacokinetic characteristics of Hyperoside-2-hydroxypropyl-β-cyclodextrin inclusion complex in rats were evaluated. Compared with Hyperoside, the results showed that maximum plasma concentration and AUC0-t indexes of Hyperoside inclusion complex in rat plasma were increased, the value of half-life time was prolonged, and the value of apparent clearance was decreased, which proved that Hyperoside complexed with 2-hydroxypropyl-β-cyclodextrin could improve its bioavailability and increase its blood concentration. Secondly, the therapeutic effect of Hyperoside before and after complexing was further compared through the dextran sodium sulfate-induced colitis in mice. The experimental results showed that under the same dose, the Hyperoside inclusion complex had a better therapeutic effect, which could significantly increase the body weight of mice, improve the disease activity index, alleviate colon shortening, improve pathological colon changes, and have a better protective effect on colitis mice. According to 16S rDNA sequencing analyses, Hyperoside-2-hydroxypropyl-β-cyclodextrin may have an anti-inflammatory effect by increasing the abundance of beneficial bacteria (e.g. Firmicuria) and decreasing the proportion of harmful bacteria (e.g. Bacteroidetes) to balance the colon's microbiota.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Animals; Colitis; Disease Models, Animal; Mice; Mice, Inbred C57BL; Quercetin; Rats

Vision loss and blindness are frequently caused by photoreceptor degeneration, for example in age-related macular degeneration and retinitis pigmentosa. However, there is no effective medicine to treat these photoreceptor degeneration-related diseases. Cell senescence is a common phenotype in many diseases; however, few studies have reported whether it occurs in photoreceptor degeneration diseases. Herein, we identified that cell senescence is associated with photoreceptor degeneration induced by N-methyl-N-nitrosourea (MNU, a commonly used photoreceptor degeneration model), presented as increased senescence-associated β-galactosidase activity, DNA damage, oxidative stress and inflammation-related cytokine Interleukin 6 (IL6), and upregulation of cyclin p21 or p16. These results suggested that visual function might be protected using anti-aging treatment. Furthermore, Hyperoside is reported to help prevent aging in various organs. In this study, we showed that Hyperoside, delivered intravitreally, alleviated photoreceptor cell senescence and ameliorated the functional and morphological degeneration of the retina in vivo and in vitro. Importantly, Hyperoside attenuated the MNU-induced injury and aging of photoreceptors via AMPK-ULK1 signaling inhibition. Taken together, our results demonstrated that Hyperoside can prevent MNU-induced photoreceptor degeneration by inhibiting cell senescence via the AMPK-ULK1 pathway.

Topics: AMP-Activated Protein Kinases; Animals; Apoptosis; Cellular Senescence; Disease Models, Animal; Methylnitrosourea; Photoreceptor Cells, Vertebrate; Retina; Retinal Degeneration

Alzheimer's disease (AD) is a highly prevalent neurodegenerative disorder characterized by the pathological hallmarks of β-amyloid plaque deposits, tau pathology, inflammation, and cognitive decline. Hyperoside, a flavone glycoside isolated from Rhododendron brachycarpum G. Don (Ericaceae), has neuroprotective effects against Aβ both in vitro and in vivo. However, whether hyperoside could delay AD pathogenesis remains unclear. In the present study, we observed if chronic treatment with hyperoside can reverse pathological progressions of AD in the APP/PS1 transgenic mouse model. Meanwhile, we attempted to elucidate the molecular mechanisms involved in regulating its effects. After 9 months of treatment, we found that hyperoside can improve spatial learning and memory in APP/PS1 transgenic mice, reduce amyloid plaque deposition and tau phosphorylation, decrease the number of activated microglia and astrocytes, and attenuate neuroinflammation and oxidative stress in the brain of APP/PS1 mice. These beneficial effects may be mediated in part by influencing reduction of BACE1 and GSK3β levels. Hyperoside confers neuroprotection against the pathology of AD in APP/PS1 mouse model and is emerging as a promising therapeutic candidate drug for AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid Precursor Protein Secretases; Animals; Aspartic Acid Endopeptidases; Cognitive Dysfunction; Disease Models, Animal; Mice, Transgenic; Neuroprotective Agents; Plaque, Amyloid; Quercetin; Time

Diabetic nephropathy is a serious complication of diabetes. Hyperoside has been widely reported to ameliorate diabetes-associated disease. The current study is designed to explore the mechanism of hyperoside in diabetic nephropathy. In the present study, high glucose was used to treat podocytes. Diabetic nephropathy mice models were established by high-fat feeding followed by multiple low dose injections of streptozocin. Western blot analysis was conducted for detection of extracellular matrix accumulation, inflammatory response and cell apoptosis. We found out that hyperoside improved high glucose-induced cell injury. Additionally, hyperoside prevented mice with diabetic nephropathy from diabetic symptoms and renal dysfunction. Mechanistically, hyperoside inhibited the mRNA and protein expression of APC. MiR-499-5p was found to be an upstream negative mediator of APC, and hyperoside induced the upregulation of miR-499-5p. MiR-499-5p bound with the 3' untranslated region of APC to inhibit its expression. Finally, rescue assays revealed that the suppressive effects of miR-499-5p overexpression on renal dysfunction were rescued by upregulation of APC in mice with diabetic nephropathy. In conclusion, these findings indicated that hyperoside ameliorates diabetic nephropathy via targeting the miR-499-5p/APC axis, suggesting that hyperoside may offer a potential tactic for diabetic nephropathy treatment.

Topics: Adenomatous Polyposis Coli Protein; Animals; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Disease Models, Animal; Gene Expression; Male; Mice, Inbred C57BL; MicroRNAs; Molecular Targeted Therapy; Podocytes; Quercetin; Streptozocin

The genus Hypericum are widely distributed in China. Hypericum perforatum L. (genus Hypericum, family Hypericaceae) has a long history as a traditional Chinese medicine, which was traditionally used for the treatment of emotional distress, cardiothoracic depression, and acute mastitis. Hyperoside (Hyp) extracted from Hypericum perforatum L. has been affirmed to exert therapeutic effects on cardiovascular diseases, with widespread existence in plants of genus Hypericum. Hyp could also be extracted from Crataegus pinnatifida Bunge (genus Crataegus pinnatifida Bunge, family Rosaceae), another traditional Chinese medicine that traditionally prevented and treated heart disease in China. The cardioprotection and mechanism of Hyp comprise anti-inflammation, anti-fibrosis, activation of autophagy, and reversal of cardiac remodeling.. This study aimed to explore the Hyp effect against MI and its underlying mechanism.. The MI model was constructed in the KM mice via a ligating surgery of the left anterior descending (LAD) coronary artery. Subsequently, the mice were divided into following seven groups: Sham group, MI group, MI + Hyp 9 mg/kg group, MI + Hyp18 mg/kg group, MI + Hyp36 mg/kg group, MI + Fosinopril group, and MI + Hyp-36 mg/kg+3-MA group. Each group was treated with Hyp in different concentrations or positive medicine for two weeks except for the sham group. After two weeks, we examined the cardiac function, electrocardiogram (ECG), myocardial hypertrophy in the non-infarct area, collagen volume fraction (CVF), perivascular collagen area (PVCA) in the infarct area, and several serum cytokines. Autophagy and inflammation in cardiomyocytes were assessed via measuring autophagy-associated proteins and NLRP1 inflammasome pathway related proteins.. Hyp reversed LV remodeling and adverse ECG changes through reducing CVF and myocardial hypertrophy. Additionally, Hyp treatment could reduce inflammation levels in cardiomyocytes, compared with those in MI group. Moreover, NLRP1inflammation pathway was activated after MI. Up-regulation of autophagic flux suppressed NLRP1 inflammation pathway after Hyp treatment. However, co-treatment with 3-MA abrogated above effects of Hyp.. Hyp had obvious protective effect on heart injury in MI mice. Echocanrdiographic and histological measurements demonstrated that Hyp treatment improved cardiac function, and ameliorated myocardial hypertrophy and fibrinogen deposition after MI. The partial mechanism is that Hyp could up-regulate autophagy after MI. Furthermore, the promotion of autophagic flux would suppress NLRP1 inflammation pathway induced by MI.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis Regulatory Proteins; Autophagy; Body Weight; Cardiotonic Agents; Cytokines; Disease Models, Animal; Electrocardiography; Heart Diseases; Hypericum; Inflammation; Male; Medicine, Chinese Traditional; Myocardial Infarction; Myocytes, Cardiac; Organ Size; Quercetin; Signal Transduction; Ventricular Remodeling

Sepsis-associated cardiac dysfunction results in increased mortality. Hyperoside (Hyp) is a flavonoid, showing significant anti-inflammatory effects. However, its pharmacological effects on sepsis-induced cardiac dysfunction remain unknown. In this study, we attempted to explore whether Hyp could prevent cardiac dysfunction and its underlying mechanisms.. We established a mice mode of sepsis by cecal ligation and puncture (CLP) treatment, and constructed a cell model of myocardial injury by lipopolysaccharide (LPS) stimulation. The cardiac function indicators and the inflammatory cytokine levels were measured. Effect of Hyp on cardiomyocyte viability was evaluated using MTT assay. The expression and functional role of microRNA-21 (miR-21), a documented molecule that regulated by Hyp, was evaluated in the constructed models, and the potential targets of miR-21 were predicted.. Hyp alleviated the impaired cardiac function and stimulated inflammation caused by CLP in the in vivo sepsis model, and alleviated the LPS-induced decrease in cell viability and increase in inflammation of cardiomyocytes. Additionally, Hyp significantly inhibited the expression of miR-21 in LPS-induced cardiomyocytes, and the increased cell viability and decreased inflammation caused by Hyp in the in vitro model could be reversed by miR-21 overexpression. In animal model of sepsis, the protective influence of Hyp against sepsis-induced cardiac dysfunction was attenuated by miR-21 upregulation.. Our findings demonstrated that Hyp may serve as a promising natural drug for the treatment of sepsis-associated cardiac dysfunction, and its protective role may exerted through regulating cardiomyocyte viability and inflammation by suppressing miR-21.

Topics: Animals; Anti-Inflammatory Agents; Cell Line; Cell Survival; Cytokines; Disease Models, Animal; Down-Regulation; Heart Diseases; Humans; Inflammation Mediators; Male; Mice, Inbred C57BL; MicroRNAs; Myocytes, Cardiac; Quercetin; Sepsis; Signal Transduction

Hypericum perforatum L. (genus Hypericum, family Hypericaceae), a plant commonly used in traditional Chinese medicine, is believed to confer a wide range of benefits, including fever reduction, detoxification, calming, and pain relief via decoctions of its stems and leaves. Hyperoside (HYP), a natural compound extracted from Hypericum perforatum L., has been shown to demonstrate a wide array of bioactivities including antioxidative, anti-inflammatory, and anti-apoptotic effects. In this study, we investigated the effects of HYP on epilepsy-induced neuronal damage in mice and the associated regulatory factors.. This study examined the potential therapeutic use of HYP for the treatment of neuronal damage in a mouse model of epilepsy and explored the relationships of the potential neuroprotective effects of HYP pretreatment with antioxidant levels and autophagy.. ICR mice were randomly divided into six groups: sham group, sham-HYP group, KA group, KA-HYP group, KA-HYP-DDC group and KA-CQ group. Immunohistochemical staining was used to assess changes in NeuN, IBA-1, and GFAP expression in the CA3 region of the hippocampus. Immunofluorescence staining was used to assess the effects of HYP on the number of autophagosomes that accumulated in neurons in the hippocampal CA3 region. The levels of SOD1, SOD2, LC3I/II, Beclin1, and PI3K/AKT and MAPK signaling-related proteins were detected by Western blot.. Pretreatment with 50 mg/kg HYP protected against epilepsy-induced neuronal damage in the hippocampal CA3 region. Additionally, HYP enhanced antioxidant levels and reduced the levels of autophagy-related proteins via the PI3K/AKT and MAPK pathways.. HYP protected the hippocampal CA3 region against epilepsy-induced neuronal damage via enhancing antioxidant levels and reducing autophagy. The mechanism of action may be related to the maintenance of antioxidant levels and the suppression of autophagy via the PI3K/Akt and MAPK pathways.

Topics: Animals; Antioxidants; Autophagosomes; Autophagy; Autophagy-Related Proteins; CA3 Region, Hippocampal; Disease Models, Animal; DNA-Binding Proteins; Kainic Acid; Male; Mice, Inbred ICR; Mitogen-Activated Protein Kinases; Nerve Degeneration; Nerve Tissue Proteins; Neurons; Neuroprotective Agents; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Quercetin; Seizures; Signal Transduction

Recurrent pregnancy loss (RPL) is one of the most common obstetrical diseases, which is a manifestation of antiphospholipid syndrome (APS) with no effective therapy methods. Autophagy and inflammatory responses both play an important role in the pathogenesis of RPL and hyperoside has been demonstrated to have multifarious bioactivities including enhancing autophagy and anti-inflammation. This study aims to investigate the effect of hyperoside on anticardiolipin (aCL)-IgG fractions-induced pregnancy loss.. In the present study, the effect of hyperoside was evaluated in a rat model of pregnancy loss induced by aCL-IgG fractions isolated from serum of APS patients. The fetuses were counted and the placentas were weighted and the protein expressions of inflammation and autophagy were measured by western blot analysis.. Treatment with hyperoside (40 mg/kg) improved pregnancy outcome manifest as increasing the weight of fetuses and decreasing the fetal resorption rate. In addition, hyperoside treatment downregulated the expressions of phosphorylated mammalian target of rapamycin (mTOR), phosphorylated p70S6 Kinase (S6K) and inhibited the expressions of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and NF-kB p-p65 in pregnancy loss animal models.. Hyperoside attenuated pregnancy loss through regulating mTOR/S6K and TLR4/MyD88/NF-kB signaling pathways, which may provide a potential drug candidate for recurrent pregnancy loss therapy.

Topics: Abortion, Habitual; Animals; Autophagy; Disease Models, Animal; Female; Inflammation; Male; Pregnancy; Pregnancy Outcome; Quercetin; Rats; Rats, Sprague-Dawley; Signal Transduction

Hyperoside, as an active compound, widely exists in a large number of Chinese herbal medicines and has been reported to possess anti-inflammatory and diuretic properties. However, the effects and underlying mechanisms of hyperoside on periodontitis have not been previously reported. In this study, we found that hyperoside ameliorates symptoms of periodontitis in a rat model, with improvements in alveolar bone resorption, relief of inflammatory infiltration, increase in orderly arrangement of collagen fibers and increase of osteogenic differentiation. In addition, hyperoside promoted proliferation, up-regulated EdU-positive cells, decreased cell-cycle distribution and increased the protein expression of Ki67 and PCNA in rat bone mesenchymal stem cells (rBMSCs), as revealed by Cell Counting Kit-8, EdU, flow cytometry and western blot analysis. Moreover, hyperoside significantly promoted osteogenic differentiation, as shown by quantitative RT-PCR, western blot and alizarin red staining assays. Furthermore, hyperoside activated the nuclear factor-κB (NF-κB) signaling pathway in rBMSCs, similar to the results observed in vivo. Finally, BMS345541, an inhibitor of the NF-κB signaling pathway, could reverse the effects of hyperoside on the biological functions in rBMSCs. In conclusion, our results suggest that hyperoside has potential therapeutic properties against periodontitis via promotion of proliferation and osteogenic differentiation of rBMSCs via activation of the NF-κB signaling pathway.

Topics: Animals; Cell Differentiation; Cells, Cultured; Disease Models, Animal; Male; Mesenchymal Stem Cells; NF-kappa B; Osteogenesis; Periodontitis; Quercetin; Rats; Rats, Sprague-Dawley

Hyperin, a flavonoid compound found in natural plants, has been reported that it have anti-inflammatory properties. However, the protective effects and mechanisms of hyperin on acute lung injury have not been reported so far. This research was designed to investigate the protective effects of hyperin on lipopolysaccharide-induced acute lung injury (ALI) in mice. The mice were stimulated with LPS in the presence or absence of hyperin and the MPO activity, lung wet/dry ratio, inflammatory cells in BALF, and cytokines, as well as NF-κB expression were assessed in lung tissue. Results showed that hyperin significantly inhibited LPS-induced histological changes, inflammatory cell infiltration, MPO activity and lung wet/dry ratio. Additionally, hyperin distinctly reduced the production of TNF-α, IL-1β and IL-6 and the activation of NF-κB signaling pathways in LPS-induced ALI in mice. In conclusion, hyperin is an effective suppressor of inflammation and may be a promising potential therapeutic reagent for ALI treatment.

Topics: Acute Lung Injury; Animals; Anti-Inflammatory Agents; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Leukocytes; Lipopolysaccharides; Lung; Mice; Peroxidase; Quercetin

Heart failure (HF) is an end-stage of various serious cardiovascular diseases, which causes liver injury. Hyperoside has been reported to exert protective effect on liver injury and fibrosis. However, the role and related mechanisms of hyperoside in HF-induced liver fibrosis are still unclear. In the current study, we established a model of HF via aortocaval fistula (ACF) in rats in vivo. Hyperoside treatment in ACF rats increased cardiac output, the maximum peak rate of rise/fall in left ventricular pressure (+dP/dt, -dP/dt) and LV ejection fraction (LVEF), decreased LV end-systolic pressure (LVESP), LV end-diastolic pressure (LVEDP) and LV end-systolic volume (LVESV), and reduced heart weight/body weight ratio in a dose-dependent manner. Moreover, hyperoside could attenuate liver fibrosis and injury in ACF rats, as evidenced by reduction of fibrosis area and hydroxyproline content, amelioration of edema and degeneration of liver cell vacuoles, and inhibition of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) levels. Further, α-smooth-muscle actin (α-SMA), collagen I, profibrotic factor-connective tissue growth factor (CTGF), matrix metalloproteinase-2 (MMP2) and MMP9 levels were down-regulated in hyperoside-treated ACF rats. Additionally, hyperoside inhibited the activation of TGF-β1/Smad pathway. Finally, we confirmed that hyperoside suppressed TGF-β1-mediated hepatic stellate cell activation in vitro. Collectively, hyperoside showed a suppressive role in HF-induced liver fibrosis and injury.

Topics: Animals; Disease Models, Animal; Heart Failure; Hepatic Stellate Cells; Liver; Liver Cirrhosis; Male; Quercetin; Rats; Rats, Wistar

Cardiac hypertrophy is a major predisposing factor for heart failure and sudden cardiac death. Hyperoside (Hyp), a flavonoid isolated from Rhododendron ponticum L., is a primary component of Chinese traditional patent medicines. Numerous studies have shown that Hyp exerts marked anti-viral, anti-inflammatory, anti-oxidant, anti-cancer, anti-ischemic, and particularly cardio-protective effects. However, the effects of Hyp on cardiac hypertrophy have not been explored. The aims of this study were to determine whether Hyp could protect against cardiac remodeling and to clarify the potential molecular mechanisms.. Neonatal rat cardiac myocytes were isolated and treated with different concentrations of Hyp, then cultured with angiotensin II for 48 h. Mice were subjected to either aortic banding or sham surgery (control group). One week after surgery, the mice were treated with Hyp (20 mg/kg/day) or vehicle by oral gavage for 7 weeks. Hypertrophy was evaluated by assessing morphological changes, echocardiographic parameters, histology, and biomarkers.. Hyp pretreatment suppressed angiotensin II-induced hypertrophy in cardiomyocytes. Hyp exerted no basal effects but attenuated cardiac hypertrophy and dysfunction, fibrosis, inflammation, and oxidative stress induced by pressure overload. Both in vivo and in vitro experiments demonstrated that the effect of Hyp on cardiac hypertrophy was mediated by blocking activation of the AKT signaling pathway.. Hyp improves cardiac function and prevents the development of cardiac hypertrophy via AKT signaling. Our results suggest a protective effect of Hyp on pressure overload-induced cardiac remodeling. Taken together, Hyp may have a role in the pharmacological therapy of cardiac hypertrophy.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Cardiomegaly; Cells, Cultured; Disease Models, Animal; Interleukin-1beta; Male; Mice; Mice, Inbred C57BL; Myocardium; Myocytes, Cardiac; Oxidative Stress; Protective Agents; Proto-Oncogene Proteins c-akt; Quercetin; Rats; Signal Transduction; Superoxide Dismutase; Ventricular Remodeling

Hyperin is a flavonoid compound derived from Ericaceae, Guttifera, and Celastraceae that has been shown to have various biological effects, such as anti-inflammatory and anti-oxidant effects. However, there is no evidence to show the protective effects of hyperin on lipopolysaccharide (LPS)-induced acute kidney injury (AKI). Therefore, we investigated the protective effects and mechanism of hyperin on LPS-induced AKI in mice. The levels of TNF-α, IL-6, and IL-1β were tested by ELISA. The effects of hyperin on blood urea nitrogen (BUN) and serum creatinine were also detected. In addition, the expression of TLR4, NF-κB, and NLRP3 were detected by western blot analysis. The results showed that hyperin significantly inhibited LPS-induced TNF-α, IL-6, and IL-1β production. The levels of BUN and creatinine were also suppressed by hyperin. Furthermore, LPS-induced TLR4 expression and NF-κB activation were also inhibited by hyperin. In addition, treatment of hyperin dose-dependently inhibited LPS-induced NLRP3 signaling pathway. In conclusion, the results showed that hyperin inhibited LPS-induced inflammatory response by inhibiting TLR4 and NLRP3 signaling pathways. Hyperin has potential application prospects in the treatment of sepsis-induced AKI.

Topics: Acute Kidney Injury; Animals; Anti-Inflammatory Agents; Blood Urea Nitrogen; Creatinine; Cytokines; Cytoprotection; Disease Models, Animal; Dose-Response Relationship, Drug; Kidney; Lipopolysaccharides; Mice, Inbred BALB C; NF-kappa B; NLR Family, Pyrin Domain-Containing 3 Protein; Quercetin; Signal Transduction; Toll-Like Receptor 4

Quercetin and hyperoside (QH) are the two main constituents of the total flavone glycosides of Flos Abelmoschus manihot, which has been prescribed for treating chronic kidney disease for decades. This study aimed to investigate the effect of QH on calcium oxalate (CaOx) formation in ethylene glycol (EG)-fed rats. Rats were divided into three groups: an untreated stone-forming group, a QH-treated stone-forming group (20 mg/kg/day) and a potassium citrate-treated stone-forming group (potassium citrate was a worldwide-recognized calculi-prophylactic medicine). Ethylene glycol (0.5 %) was administered to the rats during the last week, and vitamin D3 was force-fed to induce hyperoxaluria and kidney calcium oxalate crystal deposition. 24 h urine samples were collected before and after inducing crystal deposits. Rats were killed and both kidneys were harvested after 3 weeks. Bisected kidneys were examined under a polarized light microscope for semi-quantification of the crystal-formation. The renal tissue superoxide dismutase and catalase levels were measured by Western blot. QH and potassium citrate have the ability to alkalinize urine. The number of crystal deposits decreased significantly in the QH-treated stone-forming group as compared to the other groups. Superoxide dismutase and catalase levels also increased significantly in the QH-treated stone-forming group, as compared with the untreated stone-forming group. QH administration has an inhibitory effect on the deposition of CaOx crystal in EG-fed rats and may be effective for preventing stone-forming disease.

Topics: Animals; Calcium Oxalate; Catalase; Disease Models, Animal; Ethylene Glycol; Kidney; Kidney Calculi; Quercetin; Rats; Rats, Sprague-Dawley; Superoxide Dismutase; Treatment Outcome

The antinociceptive profile of St. John's Wort (SJW) was investigated in mice in a condition of acute thermal and chemical pain, together with the mechanism that might underlie this effect. A dried extract of SJW induced a prolonged antinociception that persisted for 120 minutes after administration. The thermal antinociception was prevented by naloxone and by the protein kinase C (PKC) activator PMA, whereas the chemical antinociception was prevented by PMA, remaining naloxone insensitive. A chloroform (CHL) and a methanol (MET) fraction, obtained to investigate the involvement of the SJW main components, hyperforin and hypericin/flavonoid, respectively, increased pain threshold with a time course comparable to the dried extract. The CHL antinociception was prevented by naloxone, whereas the MET antinociception was antagonized by PMA. Purified hyperforin and hypericin showed an antinociceptive efficacy comparable to CHL and MET, respectively. Conversely, flavonoids were devoid of any effect. The administration of yohimbine and atropine did not modify SJW, CHL and MET antinociception. These results indicate that both CHL and MET fractions mediate the SJW-induced antinociception. In particular, the presence of hypericin was fundamental to induce both thermal and chemical antinociception through the inhibition of the PKC activity, whereas hyperforin selectively produced a thermal opioid antinociception.. This article presents evidence of a persistent thermal and chemical antinociception of SJW that is mainly mediated by PKC-inhibiting mechanisms. These findings identify important targets for a longer-acting activation of endogenous pain systems and should potentially help clinicians who seek safe, tolerable, and prolonged treatments for pain relief.

Topics: Acetic Acid; Analgesics; Analgesics, Opioid; Animals; Anthracenes; Chromatography, High Pressure Liquid; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Routes; Drug Administration Schedule; Drug Compounding; Hypericum; Male; Mice; Naloxone; Naltrexone; Narcotic Antagonists; Pain; Pain Measurement; Pain Threshold; Perylene; Phorbol Esters; Phytotherapy; Protein Kinase C; Quercetin; Somatostatin; Spectrometry, Mass, Electrospray Ionization; Statistics, Nonparametric; Time Factors

The midbrain periaqueductal grey (PAG) is a structure known for its roles in pain transmission and modulation. Noxious stimuli potentiate the glutamate synaptic transmission and enhance glutamate NMDA receptor expression in the PAG. However, little is known about roles of NMDA receptor subunits in the PAG in processing the persistent inflammatory pain. The present study was undertaken to investigate NR2A- and NR2B-containing NMDA receptors in the PAG and their modulation to the peripheral painful inflammation. Noxious stimuli induced by hind-paw injection of complete Freund's adjuvant (CFA) caused up-regulation of NR2B-containing NMDA receptors in the PAG, while NR2A-containing NMDA receptors were not altered. Whole-cell patch-clamp recordings revealed that NMDA receptor mediated mEPSCs were increased significantly in the PAG synapse during the chronic phases of inflammatory pain in mice. PAG local infusion of Ro 25-6981, an NR2B antagonist, notably prolonged the paw withdrawal latency to thermal radian heat stimuli bilaterally in rats. Hyperoside (Hyp), one of the flavonoids compound isolated from Rhododendron ponticum L., significantly reversed up-regulation of NR2B-containing NMDA receptors in the PAG and exhibited analgesic activities against persistent inflammatory stimuli in mice. Our findings provide strong evidence that up-regulation of NR2B-containing NMDA receptors in the PAG involves in the modulation to the peripheral persistent inflammatory pain.

Topics: Afferent Pathways; Animals; Anti-Inflammatory Agents, Non-Steroidal; Chronic Disease; Disease Models, Animal; Excitatory Amino Acid Antagonists; Excitatory Postsynaptic Potentials; Freund's Adjuvant; Glutamic Acid; Inflammation; Male; Mice; Mice, Inbred C57BL; Nociceptors; Organ Culture Techniques; Pain Measurement; Pain, Intractable; Patch-Clamp Techniques; Periaqueductal Gray; Phenols; Piperidines; Quercetin; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Synaptic Transmission; Up-Regulation