米诺环素对大鼠脊髓损伤后线粒体细胞色素C的释放及神经细胞凋亡的影响

目的：探讨大鼠脊髓损伤后应用米诺环素（minocycline）对线粒体细胞色素C的释放及神经细胞凋亡的影响。方法：成年大鼠脊髓损伤后分为应用米诺环素腹腔注射的治疗组（A组）和应用生理盐水的对照组（B组），于损伤后不同时间点取材，采用流式细胞仪磷脂结合蛋白V，碘化丙啶（AnnexinV／PI）双标检测凋亡细胞，HE染色观察损伤脊髓组织病理变化，免疫组化染色检测胞浆中细胞色素C表达阳性的神经细胞以及BBB运动评分观察术后动物行为学。结果：HE染色镜检发现损伤脊髓组织病理学改变A组明显轻于B组；免疫组化染色A、B两组均发现凋亡的神经细胞以及胞浆中细胞色素C的阳性表达，神经细胞凋亡率及细胞色素C表达的阳性细胞率B组均〉A组（P〈0．01）；术后动物行为学观察显示，与B组比较A组大鼠后肢的运动功能显著增强，后肢反射的恢复较快。BBB运动评分B组明显小于A组（P〈0．05）。结论：米诺环素能有效抑制大鼠脊髓损伤后神经细胞凋亡以及线粒体中细胞色素C的释放，促进神经功能的恢复。

Effect of minocycline on expression of cytochrome C and neuron apoptosis after spinal cord injury in rats

Objective:To investigate the effect of minocycline on expression of cytochrome C and neuron apoptosis after spinal cord injury(SCI) in rats.Method:Fifty six adult SD rats with spinal cord injury were divided randomly into two groups:intravenous injection of minocyeline group(group A),and intravenous injection of normal saline group(group B).The rats were sacrificed at 4,8h,1,3,7,14d after surgery respectively,and then the tissue sections of injured spinal cord were stained and evaluated with the method of hematoxylin and eosin(HE),immunohistoehemistry and the flow cytometry(Annexin V/PI).The hind limb motor function after minocycline injection was determined by the Basso-Beattie-Bresnahan(BBB) locomotor open field behavioral rating test.Result:There showed more remarkable histopathological changes in group B than in group A.Expression of Cytochrome C and apoptotic cells were observed in both two groups,and the apoptotie index and expression of Cytochrome C in group B was higher than that in group A(P<0.01).From 3 days to 28 days after SCI,BBB scores were significantly higher in minocycline-treating rats compared with those in vehicle-treating rats.Conclusion:After SCI,minocycline can prohibit expression of cytochrome C,attenuate cell death and improve neurological function in the injured rat which may provide a therapeutic intervention.