ABSTRACT
Objective:To investigate the effect of liraglutide(LRG) on high glucose-induced oxidative stress injury in(H9c2) cardiomyocytes and its underlying mechanisms.Methods:A high glucose treatment was applied to H9c2 cells for 24 hours to establish an in vitro model of myocardial cell injury. Different concentrations of liraglutide(10, 100, 1000 nmol/L) were administered for intervention. Cell viability was evaluated using the CCK-8 assay, and changes in cell morphology were observed under an inverted microscope. After 24 hours of liraglutide(100 nmol/L) intervention following high glucose treatment, the levels of lactate dehydrogenase(LDH), superoxide dismutase(SOD), and malondialdehyde(MDA) in the cell supernatant were measured. RT-PCR and Western blotting were used to detect the mRNA and protein levels of silent information regulator factor 1(SIRT1) and forkhead box protein O1(FOXO1). Western blotting was also used to assess the acetylation level of FOXO1 protein. Small interfering RNA(siRNA) technology was employed to silence SIRT1 in H9c2 cells to confirm its role in the study. Results:Compared to the control group, the high glucose group showed decreased cell viability, cell structure damage, increased levels of LDH and MDA in the cell supernatant, decreased SOD levels, aggravated oxidative stress, decreased SIRT1 expression, and increased acetylation level of FOXO1(all P<0.05). Compared to the high glucose group, liraglutide intervention resulted in increased cell viability, improved cardiac cell morphology, reduced oxidative stress levels, increased SIRT1 expression, and decreased acetylation level of FOXO1(all P<0.05). When SIRT1 was downregulated, the protective effects of liraglutide were weakened(all P<0.05). Conclusions:Liraglutide has a protective effect against high glucose-induced oxidative stress injury in H9c2 cells, which may be associated with the upregulation of SIRT1 expression.
ABSTRACT
Objective To observe the effects of liraglutide on GRP78,ATF4,CHOP and TRB3 protein and mRNA expression in rats which fed with high fat diet,and to explore the effect of liraglutide on ATF4/CHOP pathway of pancreas in rats fed with high fat diets.Methods Forty-four male Wistar rats were randomly divided into the control group,high fat group,intervention group 1 and intervention group 2,11 cases in each group.The control group was fed with common food,other 3 groups were fed with high fat diet for 8 weeks.Then the intervention group 1 was given with liraglutide (100 μg · kg-1 · d-1) by subcutaneous injection;the intervention group 2 was given liraglutide (200 μg · kg-1 · d-1) by subcutaneous injection.After 2 weeks medication intervention,the rats were killed.Five rats were taken from each group and performed the hyperinsulinemic englycemic clamp experiment under waking state for calculating the glucose infusion rate (GIR).The fasting blood glucose (FBG),fasting insulin (FINS),serum free fatty acid (FFA),total cholesterol (TC),triglyeeride (TG),low density lipoprotein cholesterol (LDL-C) and high density lipoprotein(HDL) were examined,and islet beta cell function index(HOMA-β) were calculated.PCR and Western blot method were used to detect the expression of pancreas GRP78,ATF4,CHOP and TRB3 protein and mRNA.Results Compared with the control group,the levels of FBG,FFA,TC,FINS,TG and LDL-C in the high fat group were significantly increased,the levels of HDL-C,GIR and HOMA-β were significantly decreased(P＜0.05 or P＜0.01);compared with the high fat group,the levels of HDL-C,GIR and HOMA-β in the intervention group 2 were increased(P＜0.05 or P＜0.01),the other indicators were significantly decreased;compared with the intervention group 1,blood FGB,FFA,TC in the intervention group 2 were decreased,while the levels of GIR and HOMA-β were increased(P＜0.05).Compared with the control group,expression of GRP78,ATF4,CHOP and TRB3 protein and mRNA in the high fat group were significantly increased;compared with the high fat group,the expression of GRP78,ATF4,CHOP and TRB3 protein and mRNA in the intervention group 1 and 2 were gradually decreased with the liraglutide concentration increase.Conclusion Liraglutide can improve insulin resistance and protect pancreatic beta cells in a concentration-dependent manner,its mechanisms may involve in the pancreatic endoplasmic reticulum ATF4/CHOP pathway.
ABSTRACT
Objective To observe the effects of liraglutide on GRP78,ATF4,CHOP and TRB3 protein and mRNA expression in rats which fed with high fat diet,and to explore the effect of liraglutide on ATF4/CHOP pathway of pancreas in rats fed with high fat diets.Methods Forty-four male Wistar rats were randomly divided into the control group,high fat group,intervention group 1 and intervention group 2,11 cases in each group.The control group was fed with common food,other 3 groups were fed with high fat diet for 8 weeks.Then the intervention group 1 was given with liraglutide (100 μg · kg-1 · d-1) by subcutaneous injection;the intervention group 2 was given liraglutide (200 μg · kg-1 · d-1) by subcutaneous injection.After 2 weeks medication intervention,the rats were killed.Five rats were taken from each group and performed the hyperinsulinemic englycemic clamp experiment under waking state for calculating the glucose infusion rate (GIR).The fasting blood glucose (FBG),fasting insulin (FINS),serum free fatty acid (FFA),total cholesterol (TC),triglyeeride (TG),low density lipoprotein cholesterol (LDL-C) and high density lipoprotein(HDL) were examined,and islet beta cell function index(HOMA-β) were calculated.PCR and Western blot method were used to detect the expression of pancreas GRP78,ATF4,CHOP and TRB3 protein and mRNA.Results Compared with the control group,the levels of FBG,FFA,TC,FINS,TG and LDL-C in the high fat group were significantly increased,the levels of HDL-C,GIR and HOMA-β were significantly decreased(P＜0.05 or P＜0.01);compared with the high fat group,the levels of HDL-C,GIR and HOMA-β in the intervention group 2 were increased(P＜0.05 or P＜0.01),the other indicators were significantly decreased;compared with the intervention group 1,blood FGB,FFA,TC in the intervention group 2 were decreased,while the levels of GIR and HOMA-β were increased(P＜0.05).Compared with the control group,expression of GRP78,ATF4,CHOP and TRB3 protein and mRNA in the high fat group were significantly increased;compared with the high fat group,the expression of GRP78,ATF4,CHOP and TRB3 protein and mRNA in the intervention group 1 and 2 were gradually decreased with the liraglutide concentration increase.Conclusion Liraglutide can improve insulin resistance and protect pancreatic beta cells in a concentration-dependent manner,its mechanisms may involve in the pancreatic endoplasmic reticulum ATF4/CHOP pathway.