细胞自噬在糖尿病大鼠椎间盘退变中的作用

Role of autophagy in intervertebral disc degeneration in diabetic rats

目的:探讨凋亡和自噬水平在糖尿病大鼠椎间盘髓核组织中的变化及其作用。方法:SD大鼠注射链脲佐菌素(STZ)复制糖尿病模型16周后,完整获取大鼠腰椎间盘,经石蜡包埋切片、苏木素-伊红(HE)染色和阿里新蓝染色,在组织水平检测椎间盘病理变化。DNA原位末端标记法(TUNEL)检测髓核细胞凋亡率,免疫组织化学及Western blotting方法检测髓核组织凋亡和自噬水平。结果:HE和阿里新蓝染色显示糖尿病大鼠椎间盘发生退变。和正常组相比,caspase-3阳性细胞比例在糖尿病大鼠椎间盘中明显增加。TUNEL结果显示糖尿病大鼠椎间盘髓核细胞凋亡率升高。Western blotting和免疫组织化学检测发现自噬指标LC3Ⅱ/LC3Ⅰ和beclin-1表达量在糖尿病大鼠组均高于正常组。结论:STZ诱导的糖尿病可加速大鼠椎间盘退变,并且提高了髓核组织中凋亡和自噬水平。

AIM ： To explore the levels of apoptosis and autophagy in the nucleus pulposus tissues of intervertebral discs in diabetic rats. METHODS： Sixteen weeks after injection of streptozocin （STZ）, the lumbar intervertebral discs were obtained from the rats. The histological changes were observed by hematoxylin-eosin （HE） staining and alcian blue staining. The apoptosis of the nucleus pulposus cells was measured by the methods of terminal deoxynucleotidyl transferase-mediated nick-end labeling （TUNEL）, immunohistochemistry, and Western blotting. The level of autophagy in the nucleus pulposus cells was detected by Western blotting and immunohistochemistry. RESULTS： Compared with normal group, HE and alcian blue staining suggested that the intervertebral discs of the diabetic rats became degenerate. The expression of caspase-3 and the apoptotic rate were increased in intervertebral disc nucleus pulposus of the diabetic rats. The results of immunohistochemistry and Western blotting showed that the expression levels of LC3 Ⅱ/LC3 I and beclin-1 in the diabetic rats were higher than those in normal group. CONCLUSION： The STZ-induced diabetes accelerates degeneration of the intervertebral discs. In addition, the apoptosis and autophagy are increased in the intervertebral discs of diabetic rats.