大鼠脊髓全横断损伤后脊髓caspase-3的表达变化

Expression of caspase-3 in the transected spinal cord of rat

目的观察大鼠脊髓全横断(SCT)后横断端细胞凋亡及caspase-3 mRNA、蛋白的表达变化并探讨其意义。方法SD大鼠90只,手术组(SCT组)动物选择在T10节段全横断脊髓,假手术组除不横断外其余步骤相同。TUNEL法检测脊髓横断端凋亡情况,免疫组织化学、RT-PCR、Western blot技术检测不同时间点caspase-3 mRNA、蛋白表达变化。结果SCT后横断端脊髓灰质白质均检测到凋亡细胞,caspase-3在损伤周围组织呈阳性,RT-PCR、Western blot显示1d组基因及蛋白均明显上调,3d、7d、14d、21d组mRNA逐渐下降,且3d组依然高于假手术组;3d、7d、14d组蛋白逐渐下降而21d组又略有回升,且3d、21d组依然高于假手术组。结论SCT后凋亡主要在早期出现,随时间进展呈逐渐下降趋势。

Objective To observe the expression of caspase-3 in the transected spinal cord and to explore the role of caspase-3 in the transected spinal cord.Methods 90 clean adult Sprague Dawley（SD）rats were randomly divided into sham group and operating groups（SCT groups,spinal cord was transected at T10 level completely）.SCT group was subdivided into five groups：1d,3d,7d,14d and 21d according to different sacrificed time after operation.TUNEL,immunohistochemistry,RT-PCR and Western blot were performed to examine the expression of caspase-3.Results Apoptosis cells and caspase-3 positive cells were found in both of white and grey matter of the transfected spinal cord.The positive immunoreactive products of caspase-3 was mainly localized in cytoplasm and neural processes of cells.The expression level of caspase-3 mRNA and protein reached peak at 1 day after operation and then began to decrease at 3d,7d,14d and 21d after transection,but still higher than that in sham.Conclusion The apoptosis happpened mainly in early stage after the transection,and decreased gradually,but still higher than that in sham contol.