糖尿病神经痛大鼠脊髓神经元自噬的变化

Changes in autophagy in spinal neurons of rats with diabetic neuropathic pain

目的 评价糖尿病神经痛大鼠脊髓神经元自噬的变化.方法 成年雄性SD大鼠48只,体重220 ～ 250 g,采用随机数字表法,将其分为2组：对照组（C组,n=8）和糖尿病神经痛组（DNP组,n=40）.腹腔注射链脲佐菌素（STZ） 60 mg/kg建立大鼠糖尿病模型.DNP组分别于造模前1d和造模后1、2、4、8周各取8只大鼠,C组于相应时点,测定机械痛阈.DNP组于上述时点痛阈测定结束后,处死大鼠,取脊髓组织,采用Western blot法测定LC3-Ⅰ、LC3-Ⅱ、Beclin-1和p62蛋白的表达,计算LC3-Ⅱ/LC3-Ⅰ比值.结果 与C组比较,DNP组造模后2、4和8周时机械痛阈降低（P＜0.05）.与造模前比较,DNP组造模后2、4和8周时脊髓LC3-Ⅱ和Beclin-1表达上调,p62蛋白表达下调,LC3-Ⅱ/LC3-Ⅰ比值升高（P＜0.05）.结论 脊髓神经元自噬增强可能参与了大鼠糖尿病神经痛的形成和维持.

Objective To evaluate the changes in autophagy in spinal neurons of rats with diabetic neuropathic pain （DNP）.Methods Forty-eight male Sprague-Dawley rats,weighing 220-250 g,were randomly divided into control group （group C,n =8） and group DNP （n =40） using a random number table.Diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin （STZ） 60 mg/kg.Before STZ injection and at 1,2,4,and 8 weeks after STZ injection,8 rats randomly chosen from each group were used to measure mechanical pain threshold.The animals were sacrificed after measurement of mechanical pain threshold and the spinal cords were removed for determination of the expression of LC3-Ⅰ,LC3-Ⅱ,Beclin-1 and p62 protein.LC3-Ⅱ/LC3-Ⅰ ratio was calculated.Results Compared with group C,mechanical pain threshold was significantly decreased at 2,4,and 8 weeks after STZ injection in group DNP.The expression of LC3-Ⅱ and Beclin-1 in the spinal cord was significantly up-regulated,p62 protein expression was down-regulated,and LC3-Ⅱ/LC3-Ⅰ ratio was increased at 2,4,and 8 weeks after STZ injection as compared with the baseline value before STZ injection in group DNP.Conclusion Enhanced autophagy in spinal neurons may be involved in the development and maintenance of DNP in rats.