褪黑素对大鼠急性脊髓损伤内质网应激蛋白GADD153/CHOP表达的影响

目的探讨褪黑素（MT）对急性脊髓损伤（ASCI）大鼠模型脊髓组织GADD153/CHOP表达的影响。方法选取健康SD大鼠96只,随机分为生理盐水处理组（NS组）、乙醇处理组（ET组）及褪黑素治疗组（MT组）各32只。所有大鼠均以改良Allen法制备脊髓损伤模型;MT组在模型制备的基础上给予褪黑素治疗;ET组在模型制备的基础上给予5%乙醇处理;NS组在模型制备的基础上给予0.9%氯化钠溶液处理。分别于伤后3h、1d、3d、7d时各取8只应用改良Tarlov评分法评价其神经功能;Tarlov评分后处死,取受损节段脊髓行HE染色及免疫组化染色,观察形态学改变和CHOP表达的特点;并应用TUNEL方法检测神经细胞凋亡情况。其量的评定借助于麦克奥迪数码医学图像分析系统A（Motic.med6.0）软件,结果分别用累积光密度（IOD）及细胞凋亡指数（AI）来表示。结果所有实验大鼠脊髓组织均有不同程度出血、水肿、细胞凋亡及坏死。MT组Tarlov评分除3h时间点外,其他各时间点Tarlov评分明显高于ET组及NS组,且差异有统计学意义（P〈0.05或P〈0.01）。MT组与ET、NS组不同时间点CHOP表达、细胞凋亡差异有统计学意义,表现为除3h时间点外,其他各个时间点MT组CHOP表达及细胞凋亡均明显低于其余两组（P〈0.05）。而ET、NS组之间各时间点CHOP表达、细胞凋亡比较,差异无统计学意义（P〉0.05）。结论 MT可抑制CHOP表达,降低脊髓细胞凋亡指数,可能为其发挥急性脊髓损伤保护作用的重要机制之一。

The effect of melatonin on GADD153/CHOP protein expression of acute spinal cord injury rat model

Objective To explore the effect of melatonin on the expression of GADD153/CHOP of acute spinal cord injury rat model. Methods Ninety-six healthy SD rats were selected and randomly divided into normal saline treatment group （NS group）, ethanol treatment group （ET group） and melatonin treatment group （MT group）. All rats were modeled by modified Allen＇s legal system, and that of MT group was given melatonin for treatment on the basis of the modeling, while that of ET group was given equal dose of 5% ethanol and that of NS group was given equal dose of normal saline. 8 rats of each group were selected and reached respectively 3 h, 1 d, 3 d, 7 d after injury which Tarlov scores were evaluated to assess the nerve function. Tarlov scores after death, damage to the segmental spinal cord line HE staining and immunohistochemical staining, and observed the morphological changes and the characteristics of CHOP expression; And TUNEL method was applied to detection of nerve cell apoptosis. The amount assessed by mike audi digital medical image analysis system （Motic. med 6.0） software, result with cumulative optical density （integrated optical density, IOD） and apoptosis index （AI）. Results All experimental rats spinal cord tissue had different degree of hemorrhage, edema, apoptosis and necrosis. MT group Tarlov scores in addition to the 3 h time points, Tarlov scores were significantly higher than other time points in ET group and NS group, and the difference was statistically significant （P 0.05 or P 0.01）. MT group with ET group, NS group at different time points difference CHOP expression, cell apoptosis, expression was in addition to the 3 h time points, every other point in time in MT group, the CHOP expression and apoptosis of treatment group were significantly lower than the rest of the two groups （P 0.05）. And the each CHOP expression, cell apoptosis and temporal between ET group, NS group was compared, the difference was not significant （P 0.05）. Conclusion The melatonin can improve the neural function and has protective effect on acute spinal cord injury which may related to its inhibit funtion on CHOP expression and apoptosis of spinal cord.