热休克预处理对大鼠脊髓损伤的影响和意义

An Experimental Research of Hyperthermic Preconditioning on the Spinal Cord Injury

目的探讨热休克预处理对大鼠脊髓损伤的影响。方法将96只大鼠随机分为对照组,损伤组和热休克预处理组。采用静压型脊髓损伤模型,分别在伤后6H、12H、1D、2D、3D、1周、2周和3周处死动物。用原位杂交和免疫组化LSAB法检测HSP70MRNA和蛋白在以上各时点的表达。用CBS评分来评估神经功能。结果CBS评分显示,热休克预处理组在1周、2周、3周的CBS评分分别是:35±7.29,69±9.12,76.5±6.02;而损伤组分别为:21.5±6.02,45±8.48,48±6.94;前者的神经功能明显好于后者(P<0.05)。通过原位杂交和免疫组化发现,在6H、12H预处理组的HSP70MRNA阳性细胞率分别是6.18%±1.17%,2.58%±0.89%;而损伤组分别是1.92%±1.31%,0.32%±0.41%(P<0.05)。预处理组的HSP70蛋白阳性细胞数在12H至两周分别是13±3.27,20.74±4.17,27.72±2.26,43.86±4.82,15.56±3.61,6.76±1.86;损伤组分别是7.96±2.34,11.74±2.64,16.5±4.44,22.66±3.34,10.32±3.16,3.72±2.04(P<0.05)。结论热休克预处理对脊髓损伤有一定的保护作用,其保护机理可能同内源性HSP70增加有关。

Objective To assess the effects of hyperthermic preconditioning on spinal cord injury（SCI） in rats. Methods A total of 96 SD rats were divided into control（A）, trauma（B） and hyperthermic preconditioning （C） group. SCI models were made by static compression. The animals were decapitated at 6 h, 12 h, 1 d, 2 d, 3 d, 1 w, 2 w and 3 w after injury. With in situ hybridization and immunohistochemistry, the expression of HSP70 after spinal cord injury was studied at the transcript level and translation level respectively. Neurological outcome was evaluated by the combined behavioral score （CBS）. Results Neurological outcome in Group C was significantly higher than that in Group 13 （P〈0. 05）. In-situ hybridization and Immunohistochemistry analysis showed that expression of HSP70 in spinal cord elevated after hyperthermic preconditioning; furthermore, the level of HSP70 in Group C was significantly higher than that in Group 13 （P〈 0. 05）. Conclusion Hyperthermlc preconditioning might improve neurological outcome after spinal cord injury in rats, and the protective mechanism in this connection might involve the induction of HSP70 synthesis in spinal cord.