INFLUENCE OF MODERATE HYPOTHERMIA ON EXPRESSION OF HSP70 mRNA FOLLOWING FOCAL ISCHEMIA IN RATS

Objective To observe the effects of moderate hypothermia on the expression of HSP70 mRNA in focal model of transient cerebral ischemia in rats. Methods One hundred and forty-five adult rats were randomly divided into five groups: normal control group, sham-operated group, ischemia reperfusion group(H0), ischemia hypothermia group(H1), and ischemia reperfusion hypothermia (H2) group. Koizumi's ischemia/reperfusion model was used. The expression of HSP70 was measured by in situ hybridization. Results In H0 group, the expression of HSP70 emerged at 2 h after reperfusion and peaked at 24 h. In H1 and H2 groups, the positive expression of HSP70 increased significantly during 6-48 h, especially in the cortex of the frontal lobe at 3 d and 7 d, the difference was significant as compared with H0 (F=96.72-716.59, q=11.95-124.73,P0.001). The expression of HSP70 mRNA in H1 was more obvious than in H2 (q=7.56-60.49, P0.001). Conclusion The expression of HSP70 is increased by hypothermia, immediate hypothermia after ischemia is superior to reperfusion.