Study of the expression of apelin and its recoptor in ischemic myocardium in insulin-resistant rats / 中华老年医学杂志

ABSTRACT

Objective To investigate the expression of apelin and its recoptor (APJ) in myocardium in insulin-resistant CIR rats with myocardial ischemia.Methods Totally 24 male SD rats were randomly divided into three groupsIR group,IR+ischemia group,the control group (n=8 each).Rats in IR and IR+ischemia groups were fed with the high fat diet.Rats in control group were given the basic diet.The rat model of insulin resistance was assessed by fasting blood glucose (FBG),fasting insulin (Fins) and insulin resistance index (HOMA-IR).The rat model of myocardial ischemia was conducted by subcutaneous injection of isoprenaline 1 mg/kg per day in IR+ ischemia group.The other groups were injected an equal volume of saline.The expression levels of apelin and APJ mRNA in myocardium were determined by real-time-PCR.The positive expression of apelin polypeptide was detected by immunochemistry.Results Compared with the control group,the apelin average optical density was increased in IR group and was decreased in IR+ ischemia group [(0.16±0.004) vs.(0.13±0.005),(0.10±0.002) vs.(0.13±0.0050),both P＜0.05].There was a significant difference in apelin average optical density between IR group and IR+ischemia group [(0.16± 0.004) vs.(0.10±0.002),P＜0.05].Compared with the control group,the relative expression of apelin mRNA was increased in IR group [(5.89±0.36) vs.(4.40±0.24),P＜0.05]The relative expression of apelin mRNA was decreased in IR± ischemia group as compared with IR group [(2.66 ± 0.17) vs.(5.89 ± 0.36),P ＜ 0.05].The APJ mRNA relative expression was increased in IR group as compared with control group and was decreased in IR+ ischemia group as compared with IR group [(10.46±1.06) vs.(6.54±0.63),(3.31±0.31) vs.(10.46±1.06),both P＜0.05].Conclusions The expressions of apelin and APJ are inhibited in insulin-resistant rats with myocardial ischemia,which attenuates their protective effects on myocardium.