Protective effects of heat shock protein 70 on immature myocardial interstitium after ischemia reperfusion

Aim: To observe the expression of heat shock protein 70 in immature myocardial interstitium, and its influence on immature myocardial interstitium in ischemia reperfusion. Methods: 1 The experiment was carried out in the pharmacological laboratory of Tongji Medical College, Huazhong University of Science and Technology between December 2001 and June 2002. Twelve healthy newborn white rabbits of 14-21 days old were randomly divided into control group (n=6) and experimental group (n=6). 2 In the control group, the rats were given intraperitoneal injection of physiological saline (0.4 mL), and in vitro heart was taken at 24 hours after injection, and then models of Langendorff in vitro heart perfusion were routinely established, perfusion for 15 minutes and turned to operating heart for 15 minutes followed by a rest for 45 minutes, and then the perfusion was recovered for 15 minutes and turned to operating heart for 30 minutes. In the experimental group, the rats were given intraperitoneal injection of arterenol bitartrate, and in vitro heart was taken at 24 hours after injection, the methods were the same as those in the control group. 3 The content of heat shock protein 70 in myocardium was detected with western blot method. The content of hydroxyproline was calculated (A value of sample/standard A value×10 ×dilution times×1/tissue mass). The level of endothelin-1 was directly determined by means of average phase radioimmunocompetition. The t test was applied in comparing the difference of measurement data. Results: All the 12 rabbits were involved in the analysis of results. 1 The content of heat shock protein 70 in myocardium (A value) was obviously higher in the experimental group than in the control group (P < 0.01). 2 The content of hydroxyproline in myocardium in the experimental group was obviously higher than that in the control group (P < 0.01), and the serum level of endothelin-1 was obviously lower than that in the control group (P < 0.01). Conclusion: The expression of heat shock protein 70 in the immature myocardium of rabbits was induced by intraperitoneal injection of arterenol bitartrate, and it obviously increased at 24 hours after the injection, heat shock protein 70 can obviously relieve the release of endothelin and the degradation of interstitium in immature myocardium.