Expression of Heat Shock Protein27 in Rat Myocardium Damaged by Ischemia-Reperfusion

Objective Previous studies have shown that the small heat shock proteins(sHSPs) protect the myocardium from ischemia-preconditioning(I/P)-induced damage.The present study is designed to investigate whether the expression of HSP27 in the I/R-induced damaged myocardium is different in aging and young rats.Methods Sixty-four SD rats were prepared to establish I/P models and randomly divided into groups I(n=4,young control),II(n=20,young model),III(n=4,aging control),IV(n=20,aging model).Heart tissues were collected at different time after I/P-induced damage for further use.RT-PCR and Western blot analysis were performed to determine the expression of HSP27 mRNA and protein.Double immunofluorescence labeling-confocal microscopy was used to observe the translocation of HSP27 after I/P.Results(1) RT-PCR showed that the expression of HSP27 mRNA and protein did not change in aging or adult rats,but the expression of HSP27 mRNA increased after about 15 min ischemia treatment.(2) Western blot demonstrated HSP27 protein in anterior wall of left ventricle transferred from the cytosol to sites of the myofibrillar system immediately after I/P in adult rats as compared with aged rats,HSP27 was found in the myofibrillar syste after about 15 min ischemia treatment,and nearly all HSP27 transferred to cytosol after 45 min ischemia treatment.(3) Immunohistology indicated that after 15 min ischemia pretreatment,HSP27 protein shifted more to Z line and I band in adult rats than in aged rats.Conclusion The present results demonstrate that translocation ability of HSP27 in aging rat reduces,which may explain the reasons for reduced protectve effect on I/P.