Effects of heat shock protein 70 on immature myocardium and myocardial interstitium in rabbits

    SUN Zhongª²Dong, SONG Yuª²E,CHI Yiª²Fan, XIA Jiaª²Hong, YANG Tieª²Nan, XIAO Shiª²Liang, YANG Chenª²Yuan

    1Department of Cardiovascular Surgery, Qingdao Municipal Hospital, Medical College of Qingdao University, Qingdao 266011, China, 2Department of Cardiovascular Surgery, Xiehe Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China

    ¡¾Abstract¡¿ AIM: To investigate the protective effects of heat shock protein 70 (HSP70) on immature myocardium and myocardial interstitium. METHODS: Isolated working rabbit heart model was used in this study. Twelve rabbits (aged 14-21 days) were randomly divided into 2 groups: Control group (C) undergoing 45 min ischemia followed by 45 min reperfusion after distilled water was injected by intraperitoneum 24 h later, and experimental group (E) undergoing 45 min ischemia followed by 45 min reperfusion after norepinephrine was injected by intraperitoneum 24 h later. The HSP70 content, lactate dehydrogenase (LDH) and creatine kinase (CK) leakage, adenosine triphosphate (ATP) and malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, hydroxyproline (HP) and endothelin (ET) content, myocardial cell Ca2+ content, Ca2+ª²ATPase activity of mitothondia ([Ca2+ª²ATPase]m) and its Ca2+ content ([Ca2+]m), synthesizing ATP activity of mitochondria([ATP]m) and myocardial ultrastructure were tested. RESULTS: The cardiac function recovery was better in E group than C group (P<0.05). The HSP70 content, ATP content, SOD activity, HP, [Ca2+ª²ATPase]m activity and [ATP]m activity were higher in E group than C group (P<0.01). The MWC, LDH and CK leakage, MDA content, ET, myocardial cell Ca2+ content and [Ca2+]m content were lower in E group than C group (P<0.01). The myocardial ultrastructure injuries were milder in E group than in C group. CONCLUSION: HSP70 has obvious protective effects on immature myocardium and myocardial interstitium. ......