The Effects Of Glucagon-like Peptide-1 On Cardiomyocytes Induced By Hypoxia-reoxygenation

Part I Research on the different concentrations of glucagon-like peptide-1 on cardiomyocytes induced by hypoxia-reoxygenation injuryObjectives:To investigate the effects of glucagon-like peptide-1 (GLP-1) on cultured cardiomyocytes treated by hypoxia-reoxygenation(H/R) injury.Methods:1. Primary cardiomyocytes were obtained from neonatal rats and were cultured by enzymatic digestion method. Morphology of cardiomyocytes was observed by phase contramicroscope. Its molecular markers were observed by a-actin immunocytochemistry.2. Primary 72-hour cells were used in experiment and divided into 7 groups at random:control group, H/R group, H/R+GLP-1 (0.1nmol/1) group, H/R+GLP-1 (1nmol/1) group, H/R+GLP-1 (10nmol/l) group, H/R+GLP-1 (100nmol/l) group, H/R+GLP-1 (1OOOnmol/1) group.3. Comparison of the levels of LDH,MDA and SOD in different groups.4. The cardiomycocytes apotosis was detected by flow cytometry.Results:1. Cardiomyocytes were confirmed and the purity was more than 90%.2. Activity of LDH and SOD and content of MDA:Compared with normal group, activity of LDH and content of MDA both significantly increased while activity of SOD decreased in H/R group.; The GLP-1 preconditioning could significantly reverse these changes.the indexes above could be improved obviously compared with the H/R group (P<0.05) and is showing a dose-dependent while the concentration of GLP<10nmol/l.3. The result of flow cytometry:The cells in normal group concentrated in B3 district, and there is no distribution in B4 and B2 district; In H/R group it shows lots of apoptosis cells, and there still was a few of necrosis cells, and the rate of apoptosis is 29.1±4.78 there is statistically significant compared with the normal group, p<0.05; in H/R+GLP-1 group, it can reduce the distribution of cells in B2 and B4 district, that is to say, reduce the apoptosis and necrosis cells, and the rate of apoptosis decreased, there is statistically significant compared with H/R group, P<0.05 and is showing a dose-dependent while the concentration of GLP≤10 nmol/1.Conclusions:1. Hypoxia/re reoxygenation can induce injury in rat cardiomyocytes.2. GLP-1 can protect cardiomyocytes from the apoptosis induced by hypoxia-reoxygenation and 10nmol/l. is considered as the best protective concentration.PartⅡGLP-1 through P38MAPK signaling pathway protect against the Hypoxia-reoxygenation injury in cultured rat neonatal cardiomyocytes and the related mechanism analysisObjectives:1. To investigate the effects of glucagon-like peptide-1 (GLP-1) on cultured cardiomyocytes treated by hypoxia-reoxygenation(H/R) injury while using SB203580 inhibitor of P38MAPK signaling pathway.2. To analyze whether the effects of GLP-1 on cultured cardiomyocytes treated by hypoxia-reoxygenation(H/R) injury through P38MAPK signaling pathway.Methods:1. Primary cardiomyocytes were obtained from neonatal rats and were cultured by enzymatic digestion method.2. Primary 72-hour cells were used in experiment and divided into 5 groups at random:control group, H/R group, H/R+GLP-1 (10nmol/l) group, H/R+GLP-1 (100nmol/l)+SB203580 group,H/R+SB203580 group.3. Morphology of cardiomyocytes was observed by phase contramicroscope. Comparison of the levels of LDH, MDA and SOD in different groups.4. The cardiomycocytes apotosis was detected by flow cytometry.Results:1. Compared with normal group,cell growth condition became worse in the H/R group, The levels of LDH and MDA in the H/R group was significantly increased, while SOD decreased obviously and the apoptosis rate was significantly increased.2. The GLP-1 preconditioning could significantly reverse these changes. The indexes above could be improved obviously compared with the H/R group (P< 0.05).While compared with H/R+GLP-1 group, H/R+GLP-1+SB203580 group showed more protective effect (P<0.05). Conclusions:1. GLP-1 can protect cardiomyocytes from apoptosis induced by hypoxia-reoxygenation obviously.2. SB203580,the inhibitor of P38MAPK signaling pathway can partly ease the injury of cardiomyocytes. P38MAPK signaling pathway acted as one of the pathways through which GLP-1 showed protective effects.