Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of a...Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of angiogenesis during the regeneration process,we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells,thereby promoting microvascular regeneration in aged mice after spinal cord injury.In this study,we established young and aged mouse models of contusive spinal cord injury using a modified Allen method.We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord.Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro.Furthermore,intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord,thereby improving neurological function.The role of metformin was reversed by compound C,an adenosine monophosphate-activated protein kinase inhibitor,both in vivo and in vitro,suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury.These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway,thereby improving the neurological function of aged mice after spinal cord injury.展开更多
As major fuels for the small intestinal mucosa,dietary amino acids(AA)are catabolized in the mitochondria and serve as sources of energy production.The present study was conducted to investigate AA metabolism that sup...As major fuels for the small intestinal mucosa,dietary amino acids(AA)are catabolized in the mitochondria and serve as sources of energy production.The present study was conducted to investigate AA metabolism that supply cell energy and the underlying signaling pathways in porcine enterocytes.Intestinal porcine epithelial cells(IPEC-J2)were treated with different concentrations of AA,inhibitor,or agonist of mammalian target of rapamycin complex 1(mTORCl)and adenosine monophosphate activated protein kinase(AMPK),and mitochondrial respiration was monitored.The results showed that AA treatments resulted in enhanced mitochondrial respiration,increased intracellular content of pyruvic acid and lactic acid,and increased hormone-sensitive lipase mRNA expression.Meanwhile,decreased citrate synthase,isocitrate dehydrogenase alpha,and carnitine palmitoyltransferase 1 mRNA expression were also observed.We found that AA treatments increased the protein levels of phosphorylated mammalian target of rapamycin(p-mTOR),phosphorylated-p70 ribosomal protein S6 kinase,and phosphorylated-4 E-binding protein 1.What is more,the protein levels of phosphorylated AMPKα(pAMPKa)and nicotinamide adenine dinucleotide(NAD)-dependent protein deacetylase sirtuin-1(SIRT1)were decreased by AA treatments in a time depending manner.Mitochondrial bioenergetics and the production of tricarboxylic acid cycle intermediates were decreased upon inhibition of mTORCl or AMPK.Moreover,AMPK activation could up-regulate the mRNA expressions of inhibitor of nuclear factor kappa-B kinase subunit beta(Ikbk(3),integrin-linked protein kinase(ILK),unconventional myosin-Ic(Myolc),ribosomal protein S6 kinase beta-2(RPS6 Kβ2),and vascular endothelial growth factor(VEGF)-β,which are downstream effectors of mammalian target of rapamycin(mTOR).The mRNA expressions of phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit delta isoform(PIK3 CD)and5’-AMP-activated protein kinase subunit gamma-1(PRKAG1),which are upstream regulators of mTOR,were also up-regulated by AMPK activation.On the other hand,AMPK activation also down-regulated FK506-binding protein 1 A(FKBP1 A),serine/threonine-protein phosphatase 2 A 55 kDa regulatory subunit B beta isoform,phosphatase and tensin homolog(PTEN),and unc-51 like autophagy activating kinase 1(Ulkl),which are up-stream regulators of mTORCl.Taken together,these data indicated that AA regulated cellular energy metabolism through mTOR and AMPK pathway in porcine enterocytes.These results demonstrated interactions of AMPK and mTORCl pathways in AA catabolism and energy metabolism in intestinal mucosa cells of piglets,and also provided reference for using AA to remedy human intestinal diseases.展开更多
Electroacupuncture has therapeutic effects on ischemic brain injury, but its mechanism is still poorly understood. In this study, mice were stimulated by electroacupuncture at the Baihui(GV20) acupoint for 30 minute...Electroacupuncture has therapeutic effects on ischemic brain injury, but its mechanism is still poorly understood. In this study, mice were stimulated by electroacupuncture at the Baihui(GV20) acupoint for 30 minutes at 1 m A and 2/15 Hz for 5 consecutive days. A cerebral ischemia model was established by ligating the bilateral common carotid artery for 15 minutes. At 72 hours after injury, neuronal injury in the mouse hippocampus had lessened, and the number of terminal deoxynucleotide transferase-mediated d UTP nick-end labeling-positive cells reduced after electroacupuncture treatment. Moreover, expression of adenosine monophosphate-activated protein kinase α(AMPKα) and phosphorylated AMPKα was up-regulated. Intraperitoneal injection of the AMPK antagonist, compound C, suppressed this phenomenon. Our findings suggest that electroacupuncture preconditioning alleviates ischemic brain injury via AMPK activation.展开更多
Alterations in embryonic neural stem cells play crucial roles in the pathogenesis of amyotrophic lateral sclerosis. We hypothesized that embryonic neural stem cells from SOD1G93A individuals might be more susceptible ...Alterations in embryonic neural stem cells play crucial roles in the pathogenesis of amyotrophic lateral sclerosis. We hypothesized that embryonic neural stem cells from SOD1G93A individuals might be more susceptible to oxidative injury, resulting in a propensity for neurodegeneration at later stages. In this study, embryonic neural stem cells obtained from human superoxide dis- mutase 1 mutant (SOD1G93A) and wild-type (SOD1wv) mouse models were exposed to H202. We assayed cell viability with mitochondrial succinic dehydrogenase colorimetric reagent, and measured cell apoptosis by flow cytometry. Moreover, we evaluated the expression of the adenos- ine monophosphate-activated protein kinase (AMPK) ct-subunit, paired box 3 (Pax3) protein, and p53 in western blot analyses. Compared with SOD1wr cells, SOD1~93A embryonic neural stem cells were more likely to undergo H202-induced apoptosis. Phosphorylation of AMPKct in SOD1G93A cells was higher than that in SOD1wr cells. Pax3 expression was inversely correlated with the phosphorylation levels of AMPKct. p53 protein levels were also correlated with AMPKct phosphorylation levels. Compound C, an inhibitor of AMPKa, attenuated the effects of H20~. These results suggest that embryonic neural stem cells from SOD1C93A mice are more susceptible to apoptosis in the presence of oxidative stress compared with those from wild-type controls, and the effects are mainly mediated by Pax3 and p53 in the AMPKa pathway.展开更多
Rutin has anti-inflammatory, antioxidant, anti-viral, anti-tumor and immune regulatory effects. However, the neuroprotective effects of rutin in spinal cord injury are unknown. The p38 mitogen activated protein kinase...Rutin has anti-inflammatory, antioxidant, anti-viral, anti-tumor and immune regulatory effects. However, the neuroprotective effects of rutin in spinal cord injury are unknown. The p38 mitogen activated protein kinase (p38 MAPK) pathway is the most important member of the MAPK family that controls inflammation. We assumed that the mechanism of rutin in the repair of spinal cord injury is associated with the inhibition of p38 MAPK pathway. Allen’s method was used to establish a rat model of spinal cord injury. The rat model was intraperitoneally injected with rutin (30 mg/kg) for 3 days. After treatment with rutin, Basso, Beattie and Bresnahan locomotor function scores increased. Water content, tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 levels, p38 MAPK protein expression and caspase-3 and -9 activities in T8–9 spinal cord decreased. Oxidative stress related markers superoxide dismutase and glutathione peroxidase levels increased in peripheral blood. Rutin exerts neuroprotective effect through anti-oxidation, anti-inflammation, anti-apoptosis and inhibition of p38 MAPK pathway.展开更多
AIM To investigate the effect of metformin on activated hepatic stellate cells(HSCs) and the possible signaling pathways involved. METHODS A fibrotic mouse model was generated by intraperitoneal injection of carbon te...AIM To investigate the effect of metformin on activated hepatic stellate cells(HSCs) and the possible signaling pathways involved. METHODS A fibrotic mouse model was generated by intraperitoneal injection of carbon tetrachloride(CCl_4) and subsequent treatment with or without metformin. The level of fibrosis was detected by hematoxylin-eosin staining, Sirius Red staining, and immunohistochemistry. The HSC cell line LX-2 was used for in vitro studies. The effect of metformin on cell proliferation(CCK8 assay),motility(scratch test and Transwell assay), contraction(collagen gel contraction assay), extracellular matrix(ECM) secretion(Western blot), and angiogenesis(ELISA and tube formation assay) was investigated. We also analyzed the possible signaling pathways involved by Western blot analysis.RESULTS Mice developed marked liver fibrosis after intraperitoneal injection with CCl_4 for 6 wk. Metformin decreased the activation of HSCs, reduced the deposition of ECM, and inhibited angiogenesis in CCl_4-treated mice. Platelet-derived growth factor(PDGF) promoted the fibrogenic response of HSCs in vitro, while metformin inhibited the activation, proliferation, migration, and contraction of HSCs, and reduced the secretion of ECM. Metformin decreased the expression of vascular endothelial growth factor(VEGF) in HSCs through inhibition of hypoxia inducible factor(HIF)-1α in both PDGF-BB treatment and hypoxic conditions, and it down-regulated VEGF secretion by HSCs and inhibited HSC-based angiogenesis in hypoxic conditions in vitro. The inhibitory effects of metformin on activated HSCs were mediated by inhibiting the Akt/mammalian target of rapamycin(m TOR) and extracellular signal-regulated kinase(ERK) pathways via the activation of adenosine monophosphate-activated protein kinase(AMPK).CONCLUSION Metformin attenuates the fibrogenic response of HSCs in vivo and in vitro, and may therefore be useful for the treatment of chronic liver diseases.展开更多
The mammalian target of rapamycin (mTOR) pathway plays an important role in neuronal growth, proliferation and differentiation. To better understand the role of mTOR pathway involved in the induction of spinal cord ...The mammalian target of rapamycin (mTOR) pathway plays an important role in neuronal growth, proliferation and differentiation. To better understand the role of mTOR pathway involved in the induction of spinal cord injury, rat models of spinal cord injury were established by modified Allen's stall method and interfered for 7 days by intraperitoneal administration of mTOR activator adenosine triphosphate and mTOR kinase inhibitor rapamycin. At 1-4 weeks after spinal cord injury induction, the Basso, Beattie and Bresnahan locomotor rating scale was used to evaluate rat locomotor function, and immunohistochemical staining and western blot analysis were used to detect the expression of nestin (neural stem cell marker), neuronal nuclei (neuronal marker), neuron specific enolase, neurofilament protein 200 (axonal marker), glial fibrillary acidic protein (astrocyte marker), Akt, mTOR and signal transduction and activator of transcription 3 (STAT3). Results showed that adenosine triphosphate-mediated Akt/mTOR/STAT3 pathway increased endogenous neural stem cells, induced neurogenesis and axonal growth, inhibited excessive astrogliosis and improved the locomotor function of rats with spinal cord injury.展开更多
Objectives: The objective of the study is to observe the effects of ginsenoside Rb1 on indexes of body weight, body composition, blood lipid, skeletal muscle endurance, and insulin sensitivity in obese mice, probe int...Objectives: The objective of the study is to observe the effects of ginsenoside Rb1 on indexes of body weight, body composition, blood lipid, skeletal muscle endurance, and insulin sensitivity in obese mice, probe into its pharmacological action, and further explore its effects on adenosine monophosphate-activated protein kinase(AMPK) signaling pathway in skeletal muscle. Materials and Methods: Eight-week-old C57 BL/6 J mice were fed with high-fat diet for 12 weeks to establish obese mouse model. The model-establishment obese mice were randomly divided into three groups including model control group, metformin group, and ginsenoside Rb1 group. In the normal control group, normal diet was administered. The intervention period was 8 weeks. Body weight and food intake of the mice were measured regularly every week. The treadmill test was performed at weeks 3 and 7, and the oral glucose tolerance test was carried out at weeks 4 and 8. Body composition of the mice was detected by applying NMR Animal Body Composition Analyzer at week 8. Four parameters of blood lipids and free fatty acid(FFA)levels were detected. The m RNA expression of AMPKα and proliferator-activated receptor gamma coactivator-1α(PGC-1α) in skeletal muscle was examined by real-time fluorescence quantitative polymerase chain reaction, and the influence of ginsenoside Rb1 on protein expression of AMPKα, p-AMPKα, and PGC-1α was observed by western blotting. Results: The body weight(since the 5 th week of drug administration)and food intake of the mice in the ginsenoside Rb1 group were significantly lower than those in the model control group(P < 0.05) in a time-dependent manner. Ginsenoside Rb1 could significantly reduce the levels of triglyceride and low-density lipoprotein cholesterol, while increase the high-density lipoprotein cholesterol level(P < 0.05). In addition, ginsenoside Rb1 could reduce the serum FFA level(P < 0.05).After the administration of ginsenoside Rb1 for 8 weeks, the body fat mass of obese mice decreased and the lean mass increased(P < 0.05).The skeletal muscle endurance and the oral glucose tolerance of the obese mice improved using ginsenoside Rb1. At the molecular level,ginsenoside Rb1 could up-regulate the mRNA and protein expression of AMPKα in skeletal muscle, and increase the content of p-AMPK protein significantly(P < 0.01). At the same time, the mRNA and protein level of PGC-1α was also un-regulated, correspondingly(P < 0.01).Conclusion: Ginsenoside Rb1 exerts effects on reducing body weight, decreasing blood lipid levels, enhancing the skeletal muscle endurance,and increasing the insulin sensitivity in obese mice by activating the related proteins in AMPK signaling pathway in skeletal muscle.展开更多
基金supported by the Natural Nature Science Foundation of China,Nos.82030071,81874004the Science and Technology Major Project of Changsha,No.kh2103008(all to JZH).
文摘Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of angiogenesis during the regeneration process,we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells,thereby promoting microvascular regeneration in aged mice after spinal cord injury.In this study,we established young and aged mouse models of contusive spinal cord injury using a modified Allen method.We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord.Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro.Furthermore,intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord,thereby improving neurological function.The role of metformin was reversed by compound C,an adenosine monophosphate-activated protein kinase inhibitor,both in vivo and in vitro,suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury.These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway,thereby improving the neurological function of aged mice after spinal cord injury.
基金funded by the National Natural Science Foundation of China(31672433,31560640),ChinaSpecial fund for scientific innovation strategy-construction of high level Academy of Agriculture Science-the Outstanding Talents Training Program of Guangdong Academy of Agricultural Sciences(R2018PY-JC001),ChinaSpecial fund for scientific innovation strategy-construction of high level Academy Of Agriculture Science-The Talents Training Program Of Guangdong Academy Of Agricultural Sciences-Young Associate Researcher(R2018PY-QF001),China.
文摘As major fuels for the small intestinal mucosa,dietary amino acids(AA)are catabolized in the mitochondria and serve as sources of energy production.The present study was conducted to investigate AA metabolism that supply cell energy and the underlying signaling pathways in porcine enterocytes.Intestinal porcine epithelial cells(IPEC-J2)were treated with different concentrations of AA,inhibitor,or agonist of mammalian target of rapamycin complex 1(mTORCl)and adenosine monophosphate activated protein kinase(AMPK),and mitochondrial respiration was monitored.The results showed that AA treatments resulted in enhanced mitochondrial respiration,increased intracellular content of pyruvic acid and lactic acid,and increased hormone-sensitive lipase mRNA expression.Meanwhile,decreased citrate synthase,isocitrate dehydrogenase alpha,and carnitine palmitoyltransferase 1 mRNA expression were also observed.We found that AA treatments increased the protein levels of phosphorylated mammalian target of rapamycin(p-mTOR),phosphorylated-p70 ribosomal protein S6 kinase,and phosphorylated-4 E-binding protein 1.What is more,the protein levels of phosphorylated AMPKα(pAMPKa)and nicotinamide adenine dinucleotide(NAD)-dependent protein deacetylase sirtuin-1(SIRT1)were decreased by AA treatments in a time depending manner.Mitochondrial bioenergetics and the production of tricarboxylic acid cycle intermediates were decreased upon inhibition of mTORCl or AMPK.Moreover,AMPK activation could up-regulate the mRNA expressions of inhibitor of nuclear factor kappa-B kinase subunit beta(Ikbk(3),integrin-linked protein kinase(ILK),unconventional myosin-Ic(Myolc),ribosomal protein S6 kinase beta-2(RPS6 Kβ2),and vascular endothelial growth factor(VEGF)-β,which are downstream effectors of mammalian target of rapamycin(mTOR).The mRNA expressions of phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit delta isoform(PIK3 CD)and5’-AMP-activated protein kinase subunit gamma-1(PRKAG1),which are upstream regulators of mTOR,were also up-regulated by AMPK activation.On the other hand,AMPK activation also down-regulated FK506-binding protein 1 A(FKBP1 A),serine/threonine-protein phosphatase 2 A 55 kDa regulatory subunit B beta isoform,phosphatase and tensin homolog(PTEN),and unc-51 like autophagy activating kinase 1(Ulkl),which are up-stream regulators of mTORCl.Taken together,these data indicated that AA regulated cellular energy metabolism through mTOR and AMPK pathway in porcine enterocytes.These results demonstrated interactions of AMPK and mTORCl pathways in AA catabolism and energy metabolism in intestinal mucosa cells of piglets,and also provided reference for using AA to remedy human intestinal diseases.
基金supported by the National Natural Science Foundation of China,No.81273821
文摘Electroacupuncture has therapeutic effects on ischemic brain injury, but its mechanism is still poorly understood. In this study, mice were stimulated by electroacupuncture at the Baihui(GV20) acupoint for 30 minutes at 1 m A and 2/15 Hz for 5 consecutive days. A cerebral ischemia model was established by ligating the bilateral common carotid artery for 15 minutes. At 72 hours after injury, neuronal injury in the mouse hippocampus had lessened, and the number of terminal deoxynucleotide transferase-mediated d UTP nick-end labeling-positive cells reduced after electroacupuncture treatment. Moreover, expression of adenosine monophosphate-activated protein kinase α(AMPKα) and phosphorylated AMPKα was up-regulated. Intraperitoneal injection of the AMPK antagonist, compound C, suppressed this phenomenon. Our findings suggest that electroacupuncture preconditioning alleviates ischemic brain injury via AMPK activation.
基金supported by a grant from the National Natural Sciences Foundation of China,No.81030019
文摘Alterations in embryonic neural stem cells play crucial roles in the pathogenesis of amyotrophic lateral sclerosis. We hypothesized that embryonic neural stem cells from SOD1G93A individuals might be more susceptible to oxidative injury, resulting in a propensity for neurodegeneration at later stages. In this study, embryonic neural stem cells obtained from human superoxide dis- mutase 1 mutant (SOD1G93A) and wild-type (SOD1wv) mouse models were exposed to H202. We assayed cell viability with mitochondrial succinic dehydrogenase colorimetric reagent, and measured cell apoptosis by flow cytometry. Moreover, we evaluated the expression of the adenos- ine monophosphate-activated protein kinase (AMPK) ct-subunit, paired box 3 (Pax3) protein, and p53 in western blot analyses. Compared with SOD1wr cells, SOD1~93A embryonic neural stem cells were more likely to undergo H202-induced apoptosis. Phosphorylation of AMPKct in SOD1G93A cells was higher than that in SOD1wr cells. Pax3 expression was inversely correlated with the phosphorylation levels of AMPKct. p53 protein levels were also correlated with AMPKct phosphorylation levels. Compound C, an inhibitor of AMPKa, attenuated the effects of H20~. These results suggest that embryonic neural stem cells from SOD1C93A mice are more susceptible to apoptosis in the presence of oxidative stress compared with those from wild-type controls, and the effects are mainly mediated by Pax3 and p53 in the AMPKa pathway.
基金supported in part by grants from the Young Scientists Awards Foundation of Shandong Province of China,No.BS2013YY049the China Postdoctoral Science Foundation,No.2012M511036
文摘Rutin has anti-inflammatory, antioxidant, anti-viral, anti-tumor and immune regulatory effects. However, the neuroprotective effects of rutin in spinal cord injury are unknown. The p38 mitogen activated protein kinase (p38 MAPK) pathway is the most important member of the MAPK family that controls inflammation. We assumed that the mechanism of rutin in the repair of spinal cord injury is associated with the inhibition of p38 MAPK pathway. Allen’s method was used to establish a rat model of spinal cord injury. The rat model was intraperitoneally injected with rutin (30 mg/kg) for 3 days. After treatment with rutin, Basso, Beattie and Bresnahan locomotor function scores increased. Water content, tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 levels, p38 MAPK protein expression and caspase-3 and -9 activities in T8–9 spinal cord decreased. Oxidative stress related markers superoxide dismutase and glutathione peroxidase levels increased in peripheral blood. Rutin exerts neuroprotective effect through anti-oxidation, anti-inflammation, anti-apoptosis and inhibition of p38 MAPK pathway.
基金Supported by National Natural Science Foundation of China,No.81370590
文摘AIM To investigate the effect of metformin on activated hepatic stellate cells(HSCs) and the possible signaling pathways involved. METHODS A fibrotic mouse model was generated by intraperitoneal injection of carbon tetrachloride(CCl_4) and subsequent treatment with or without metformin. The level of fibrosis was detected by hematoxylin-eosin staining, Sirius Red staining, and immunohistochemistry. The HSC cell line LX-2 was used for in vitro studies. The effect of metformin on cell proliferation(CCK8 assay),motility(scratch test and Transwell assay), contraction(collagen gel contraction assay), extracellular matrix(ECM) secretion(Western blot), and angiogenesis(ELISA and tube formation assay) was investigated. We also analyzed the possible signaling pathways involved by Western blot analysis.RESULTS Mice developed marked liver fibrosis after intraperitoneal injection with CCl_4 for 6 wk. Metformin decreased the activation of HSCs, reduced the deposition of ECM, and inhibited angiogenesis in CCl_4-treated mice. Platelet-derived growth factor(PDGF) promoted the fibrogenic response of HSCs in vitro, while metformin inhibited the activation, proliferation, migration, and contraction of HSCs, and reduced the secretion of ECM. Metformin decreased the expression of vascular endothelial growth factor(VEGF) in HSCs through inhibition of hypoxia inducible factor(HIF)-1α in both PDGF-BB treatment and hypoxic conditions, and it down-regulated VEGF secretion by HSCs and inhibited HSC-based angiogenesis in hypoxic conditions in vitro. The inhibitory effects of metformin on activated HSCs were mediated by inhibiting the Akt/mammalian target of rapamycin(m TOR) and extracellular signal-regulated kinase(ERK) pathways via the activation of adenosine monophosphate-activated protein kinase(AMPK).CONCLUSION Metformin attenuates the fibrogenic response of HSCs in vivo and in vitro, and may therefore be useful for the treatment of chronic liver diseases.
文摘The mammalian target of rapamycin (mTOR) pathway plays an important role in neuronal growth, proliferation and differentiation. To better understand the role of mTOR pathway involved in the induction of spinal cord injury, rat models of spinal cord injury were established by modified Allen's stall method and interfered for 7 days by intraperitoneal administration of mTOR activator adenosine triphosphate and mTOR kinase inhibitor rapamycin. At 1-4 weeks after spinal cord injury induction, the Basso, Beattie and Bresnahan locomotor rating scale was used to evaluate rat locomotor function, and immunohistochemical staining and western blot analysis were used to detect the expression of nestin (neural stem cell marker), neuronal nuclei (neuronal marker), neuron specific enolase, neurofilament protein 200 (axonal marker), glial fibrillary acidic protein (astrocyte marker), Akt, mTOR and signal transduction and activator of transcription 3 (STAT3). Results showed that adenosine triphosphate-mediated Akt/mTOR/STAT3 pathway increased endogenous neural stem cells, induced neurogenesis and axonal growth, inhibited excessive astrogliosis and improved the locomotor function of rats with spinal cord injury.
基金supported by Natural Science Foundation of China (NSFC81503540&NSFC81274041)Chaoyang District Science and Technology Commission Collaborative Innovation Project (CYXC1513)+1 种基金Major New Drug Creation Sub-project (2012ZX09103201-005)Beijing Joint Construction Project (0101216-14&0101216-2013)
文摘Objectives: The objective of the study is to observe the effects of ginsenoside Rb1 on indexes of body weight, body composition, blood lipid, skeletal muscle endurance, and insulin sensitivity in obese mice, probe into its pharmacological action, and further explore its effects on adenosine monophosphate-activated protein kinase(AMPK) signaling pathway in skeletal muscle. Materials and Methods: Eight-week-old C57 BL/6 J mice were fed with high-fat diet for 12 weeks to establish obese mouse model. The model-establishment obese mice were randomly divided into three groups including model control group, metformin group, and ginsenoside Rb1 group. In the normal control group, normal diet was administered. The intervention period was 8 weeks. Body weight and food intake of the mice were measured regularly every week. The treadmill test was performed at weeks 3 and 7, and the oral glucose tolerance test was carried out at weeks 4 and 8. Body composition of the mice was detected by applying NMR Animal Body Composition Analyzer at week 8. Four parameters of blood lipids and free fatty acid(FFA)levels were detected. The m RNA expression of AMPKα and proliferator-activated receptor gamma coactivator-1α(PGC-1α) in skeletal muscle was examined by real-time fluorescence quantitative polymerase chain reaction, and the influence of ginsenoside Rb1 on protein expression of AMPKα, p-AMPKα, and PGC-1α was observed by western blotting. Results: The body weight(since the 5 th week of drug administration)and food intake of the mice in the ginsenoside Rb1 group were significantly lower than those in the model control group(P < 0.05) in a time-dependent manner. Ginsenoside Rb1 could significantly reduce the levels of triglyceride and low-density lipoprotein cholesterol, while increase the high-density lipoprotein cholesterol level(P < 0.05). In addition, ginsenoside Rb1 could reduce the serum FFA level(P < 0.05).After the administration of ginsenoside Rb1 for 8 weeks, the body fat mass of obese mice decreased and the lean mass increased(P < 0.05).The skeletal muscle endurance and the oral glucose tolerance of the obese mice improved using ginsenoside Rb1. At the molecular level,ginsenoside Rb1 could up-regulate the mRNA and protein expression of AMPKα in skeletal muscle, and increase the content of p-AMPK protein significantly(P < 0.01). At the same time, the mRNA and protein level of PGC-1α was also un-regulated, correspondingly(P < 0.01).Conclusion: Ginsenoside Rb1 exerts effects on reducing body weight, decreasing blood lipid levels, enhancing the skeletal muscle endurance,and increasing the insulin sensitivity in obese mice by activating the related proteins in AMPK signaling pathway in skeletal muscle.