大剂量甲基强地松龙对大鼠脊髓损伤后iNOS表达及细胞凋亡的影响

Effect of High Dose Methylprednisolone on Expression of iNOS and Apoptosis after Spinal Cord Injury in Rats

目的 :探讨大鼠脊髓损伤后应用大剂量甲基强地松龙 (MP)对诱导型一氧化氮合酶 (iNOS)表达及细胞凋亡的影响。方法 :成年大鼠随机分为脊髓损伤后应用大剂量甲基强的松龙治疗组 (A组 )和应用生理盐水对照组 (B组 ) ,损伤后不同时间点 (4h、8h、1d、3d、7d、14d、2 1d)按Tarlov标准评价大鼠双后肢神经功能恢复情况 ,然后处死。用HE染色观察损伤脊髓组织病理变化 ,用免疫组化染色检测iNOS阳性细胞 ,原位末端标记法 (TUNEL法 )标记凋亡细胞。结果 :HE染色镜检发现脊髓组织病理学改变A组明显轻于B组。A、B两组均发现凋亡细胞及iNOS表达 ,神经细胞凋亡指数及iNOS表达均为B组 >A组 (P <0 .0 1)。结论 :大剂量甲基强的松龙能抑制大鼠脊髓损伤后iNOS表达及细胞凋亡。

Objective: To investigate the effect of high dose methylprednisolone on expression of iNOS and apoptosis after spinal cord injury(SCI) in rats.Methods:Adult SD rats were divided at random into two groups:with Allen's weight drop to cause spinal cord injury and use high dose methylprednisolone group(group A),and use normal saline group(group B).After operation the rats were observed Tarlov's scores on neurofunction recovery of bilateral hind limbs at 4h,8h,1d,3d,7d,14d and 21d after surgery,and were sacrificed,then the tissue sections were stained with hematoxylin and eosin(HE),immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end lebeling(TUNEL) method,and the injured spinal cord tissue was evaluated.Results:The histopathology changes in spinal cord tissue observed with HE staining microscopic examination in group B was worse than that in group A.Expression of iNOS and apoptotic cells were observed in two groups,and the apoptotic index and expression of iNOS in group B is higher than that in group A( P<0.01 ).Conclusion:This study demonstrated that high dose methylprednisolone could inhibit expression of iNOS and apoptosis after SCI in rats.