Ghrelin Inhibits Apoptosis Induced By Oxidative Stress In Adult Rat Cardiomyocytes, Throught The PI3K-Akt Signaling Pathway

Ghrelin inhibits apoptosis induced by high glucose and in adult rat cardiomyocytes,through the PI3K-Akt signaling pathwayObjective The aim of the present study was to observe the impact of ghrelin on apoptosis induced by high glucose and sodium palmitate and its mechanism of anti-apoptosis.Methods isolate and culture cardiomyocytes from hearts of adult rats.Use high glucose and sodium palmitate to stimulate oxidative stress of cardiomyocytes. Apoptosis was detected by annexin-v-FITC/PI binding assay and Caspase 3 Activity assay.Reactive oxygen species were tested by DCFH-DA fluorescent probe. Phospho-Akt,phospho-Erk,NFκB were identified by ELISA assays.Expression of anti-apoptosis genes wwere detecteded by realtimePCR and western blot.Results①ghrelin inhibited apoptosis induced by high glucose and sodium palmitate in cardiomyocytes(p＜0.05),but it could not reduce the oxidative stress in cardiomyocytes.②anti-apoptotic effect of ghrelin could be blocked by wortmannin(p＜0.05),but PD98059 had no influence on it.③activation of extracellular signal-regulated kinase-1/2 and Akt serine kinases by ghrelin,peaked at 10min and 20min respectively.Ghrelin stimulated transposition of NFκB to nucleus and peaked at 30min.④transposition of NFκB to nucleus stimulated by Ghrelin was inhibited by wortaminin.⑤The expression of c-iap was 17.9 times compared with control group after ghrelin stimulating for 8h.And the expressions of bcl-2,bcl-xl and c-fos were elevated 12.2,4.4 and 4.3 times respectively after ghrelin stimulating for 20h when compared with contrls.⑥after stimulating for 24h with 1μghrelin,the protein levels of IAP-1 and Bcl-2 in cardiomycytes increased 3.67- and 2.59-fold that of control group.Conclusion These findings provided the evidence that ghrelin could inhibit apoptosis induced by oxidative stress in cardiomyocytes,but ghrelin could not reduce oxidiative stress in cells.And ghrelin produced anti-apoptotic effects through activation of PI3K/Akt pathway which promoted phosphorylation of BAD and activation of NFκB to increase expression of anti-apoptotic genes. Decreased expression of p85αin myocardium of spontaneous diabetes ratsObjective The aim was to study the molecular and cellular mechanism of cardiomyopath in long-term diabetes.Method OLETF rats and LETO rats were used as experimental and control group. Gene chip,real-time PCR,western blotting analysis were applied to show the different expressions of P85αbetween OLETF and LETO rats.Results compared with LETO rats,the concentrations of average plasma insulin in OLETF rats was lower(0.27±0.13 vs.2.39±0.34 ng/ml,p＜0.000),the triglyceride and cholesterol level were higher(1.73±0.34 vs.0.48±0.08 mmol/L,p＜0.000; 4.41±0.21 vs.2.25±0.75 mmol/L,p＜0.001),and the velocity of left ventricular diastole of OLETF rats decreased by 30%(p＜0.05).The result of microarray assays indicated an 8-fold fall-off in the expression of p85αmRNA in myocardium of OLEFT rats.The real-time PCR assays and immunoblot analysis further supported the point with the gene transcription and protein expression levels of p85αdecreased by 81.5%and 43.2%respectively(p＜0.05 and p＜0.001).Conclusion these results indicated that reduction of gene transcription and protein expression of p85αin myocardium of OLETF rats was related to impaired construction functions.