米诺环素对黑质急性炎症的保护作用及与自噬相关性研究

Protective effect of minocycline on acute inflammation in substantia nigra and its correlation with autophagy

目的观察米诺环素对脂多糖(Lipopolysaccharide,LPS)模型小鼠黑质急性炎症的保护作用,并探讨其作用机制。方法选取3月龄C57BL雄性小鼠,设立对照组、LPS组、中剂量米诺环素组(50 mg M组)、高剂量米诺环素组(75 mg M组)及75 mg M+LPS组、50 mg M+LPS组、25 mg M+LPS组,其中LPS组为单次腹腔注射LPS(5 mg/kg)。随后进行爬杆试验的行为学检测;并采用免疫组化法观察黑质部位小胶质细胞数量,免疫印迹法检测小鼠黑质部位α-突触核蛋白(α-synuclein)、LC3-Ⅱ、P62和HDAC6蛋白表达量。结果与LPS组相比,75 mg M+LPS组小鼠爬杆速度下降更显著(P<0.05),25 mg M+LPS组及50 mg M+LPS组小鼠爬杆速度则较LPS组明显加快(P<0.01);25 mg M+LPS组及50 mg M+LPS组小鼠黑质部位小胶质细胞的活化数量减少,且α-synuclein、LC3-Ⅱ、p62、HDAC6蛋白水平下降(P<0.01),而75 mg M+LPS组α-synuclein、LC3-Ⅱ、p62、HDAC6蛋白水平有所增加(P<0.05)。结论低、中剂量米诺环素不仅能减轻LPS单次腹腔注射造成的小鼠黑质部位急性炎症反应,而且能缓解该部位出现的自噬功能障碍,减少p62和α-synuclein黑质部位的积聚,改善小鼠的运动能力。

Objective To investigate the effect of minocyclein on acute inflammation in the substantia nigra caused by systemic inflammation and its mechanism.Methods 3-months male C57BL mice were randomly divided into seven groups,which were the normal saline group,the LPS group,75 mg M+LPS group,50 mg M+LPS group,25 mg M+LPS group,75 mg M+saline group and 50 mg M+saline group(75 mg M,50 mg M and 25 mg M representing 75 mg/kg,50 mg/kg,and 25 mg/kg minocycline).The LPS group was treated by single intraperitoneal injection of Lipopolysaccharide(LPS)(5 mg/kg).The climbing bar test was carried out one day before and one day after LPS injection.The number of microglia in the substantium nigra were observed by immunohistochemistry,and the expression levels of α-synuclein,LC3,P62 and HDAC6 in the substantium nigra were detected by western blotting.Results Compared with the LPS group,the climbing speed of mice in the 75 mg M+LPS group decreased(P<0.05),while those in the 25 mg M+LPS group and 50 mg M+LPS group improved significantly(P<0.01).The low and medium dose of minocycline reduced the number of activated microglia and down-regulated the protein expression levels ofα-synuclein,LC3-Ⅱ,p62 and HDAC6(P<0.01),while which were all increased in 75 mg M+LPS group(P<0.05).Conclusions Low and medium dose of minocycline could alleviate the acute inflammation and the autophagic dysfunction of the substantia nigra caused by LPS.And besides,reduce the accumulation of p62 and α-synuclein in substantia nigra,and improve the motor ability of mice.