胰岛素对大鼠脊髓损伤细胞凋亡及iNOS、COX-2表达的影响

目的 观察胰岛素对急性脊髓损伤后细胞凋亡及相关炎症因子表达的影响,探讨胰岛素对脊髓损伤保护作用的分子机制.方法 60只SD大鼠随机分为损伤对照组和胰岛素治疗组,建立SCI模型;术后8 h、1d、3 d、7 d、14 d处死动物取材,采用原位末端标记(TUNEL)和免疫组织化学观察脊髓细胞凋亡及iNOS、COX-2表达变化,并进行比较分析.结果 术后各时相胰岛素治疗组TUNEL阳性细胞的数目明显少于损伤对照组;胰岛素治疗组iNOS、COX-2的表达率明显比对照组降低,差异有显著性(P＜0.05,P＜0.01).结论 初步研究表明胰岛素对急性脊髓损伤有保护作用,抑制炎症因子iNOS、COX-2的表达是其可能作用机制之一.

Effect of insulin on neuronal apoptosis and expression of iNOS and COX-2 after acute spinal cord injury in rats

Objective] To observe the effect of insulin on neuronal apoptosis and the expression of iNOS and COX-2, and to study the molecular mechanism of protective effects of insulin against spinal cord injury. Methods] 60 SD rats were divided into two groups, control group and insulin group. The animal SCI model was established with Allen's method. The rats were killed on the 8 h, 1 d, 3 d, 7 d, and 14 d postoperatively (n=6 in each time point). Apoptosis neurons were labeled with TUNEL dyeing, and the expression of iNOS and COX-2 was tested with immunohistochemistry technique. Results] 8 h, 1 d, 3 d, 7 d, and 14 d after operation, the number of positive TUNEL staining cells was less in insulin group than in control group. Immunohistochemical staining revealed that the expressio of iNOS and COX-2 was lower in insulin group than in control group in 8 h, 1 d, 3 d, 7 d, and 14d after injury (P <0.05 or P <0.01). Conclusion] Insulin can protect injured spinal cord through inhibiting the expression of iNOS and COX-2, which may be one of the protective mechanisms of insulin against spinal cord injury.