自噬参与DJ-1保护大鼠黑质多巴胺能神经元抵抗鱼藤酮损伤

Autophagy is involved in DJ-1 protecting against rotenone-induced dopaminergic neurons injuries of substantia nigra in rats

目的观察过表达DJ-1是否缓解鱼藤酮致SD大鼠中脑黑质多巴胺能神经元损伤及其机制。方法在大鼠黑质致密部注射携带DJ-1、LacZ或者GFP-DJ-1、GFP的腺相关病毒颗粒,4周后注射鱼藤酮。通过免疫组织化学方法鉴定基因表达情况,并检测TH阳性神经元数量,验证DJ-1保护作用。通过Western blotting方法检测自噬相关蛋白表达水平。结果鱼藤酮损伤4周时,可见过表达DJ-1组大鼠损伤侧黑质的TH阳性神经元数目显著高于单纯鱼藤酮损伤组,差异有统计学意义(P<0.05)。蛋白印迹检测动物损伤侧黑质自噬相关蛋白Beclin1、p-mTOR的表达和LC3Ⅱ/Ⅰ的比值,发现DJ-1过表达组中Beclin1与LC3Ⅱ/Ⅰ的比值均较对照组增加,差异有统计学意义;而p-mTOR的表达较对照组降低,差异有统计学意义(P<0.05)。结论 DJ-1能抵抗鱼藤酮对大鼠黑质多巴胺能神经元的损伤,DJ-1能上调自噬水平。

Objective To observe whether DJ - 1 overexpression could attenuate rotenone-induced dopaminergic neurons injuries in substantia nigra （SN） of rats and its mechanism. Methods AAV vectors encoding human wild-type DJ - 1, LacZ or GFP - DJ - 1, GFP genes were stereotactically injected into the rat SN 4 weeks prior to rotenone lesion in SN. As identification of DJ - 1 gene expression by immunohistochemistry, the numbers of TH positive neurons were detected to verify the neuron-protective effect of DJ - 1. Autophagy- related proteins expression were investigated via Western blotting. Results After 4 weeks rotenone injected, the numbers of TH positive neurons increased significantly in impaired SN of rats in DJ - 1 overexpressing group compared to rotenone-injected rats （ P 〈 0. 05 ）. Autophagy-related protein Beclinl, p-mTOR expression and LC3 Ⅱ / Ⅰ ratio were detected in impaired SN of animals according to Western blotting. In DJ - 1 overexpression group, Beclin 1 expression and the ratio of LC3 Ⅱ to LC3I increased significantly compared with control groups, while p-mTOR protein expression decreased significantly compared with control groups （ P 〈 0. 05 ）. Conclusion DJ - 1 could attenuate dopaminergic cells injuries induced by rotenone and upregnlated autophagy level.