丹酚酸A复合右美托咪定对脑缺血-再灌注损伤大鼠海马神经元凋亡的影响

Effect of salvianolic acid A combined with dexmedetomidine on apoptosis of hippocampal neurons in rats with cerebral ischemia-reperfusion injury

目的探讨丹酚酸A复合右美托咪定对脑缺血-再灌注损伤大鼠海马神经元凋亡及Sirt1-p53通路的影响。方法选择SD大鼠90只,体重160~230 g,随机分为五组:假手术组(S组)、缺血-再灌注组(IR组)、丹酚酸A干预组(A组)、右美托咪定干预组(D组)、丹酚酸A复合右美托咪定干预组(AD组),每组18只。采用线栓法建立大脑中动脉缺血-再灌注损伤模型。脑缺血-再灌注24 h后,检测大鼠血流动力学情况,Morris水迷宫实验观察第1、2、3、4、5天逃避潜伏期、穿越平台次数,评估神经功能缺损评分。采用TUNEL法检测海马神经细胞凋亡,黄嘌呤氧化酶法测定SOD活性,硫化巴比妥酸法测定MDA含量,免疫组织化学法检测海马组织Bcl-2和Bax蛋白含量,Western blot法检测海马组织Sirt1和乙酰化p53蛋白含量。结果与S组比较,IR组、A组、D组和AD组第1、2、3、4、5天逃避潜伏期明显延长(P<0.05),穿越平台次数明显减少(P<0.05),HR明显减慢(P<0.05),MAP、CO明显降低(P<0.05),神经功能缺损评分明显升高(P<0.05),海马组织凋亡细胞百分比、MDA含量、Bax和乙酰化p53蛋白含量明显升高(P<0.05),海马组织SOD活力、Bcl-2和Sirt1蛋白含量明显降低(P<0.05)。与IR组比较,A组、D组和AD组第1、2、3、4、5天逃避潜伏期明显缩短(P<0.05),穿越平台次数明显增多(P<0.05),HR明显增快(P<0.05),MAP、CO明显升高(P<0.05),神经功能缺损评分明显降低(P<0.05),海马组织凋亡细胞百分比、MDA含量、Bax和乙酰化p53蛋白含量明显降低(P<0.05),海马组织SOD活力、Bcl-2和Sirt1蛋白含量明显升高(P<0.05)。与A组、D组比较,AD组第1、2、3、4、5天逃避潜伏期明显缩短(P<0.05),穿越平台次数明显增多(P<0.05),HR明显增快(P<0.05),MAP、CO明显升高(P<0.05),神经功能缺损评分明显降低(P<0.05),海马组织细胞凋亡百分比、MDA含量、Bax和乙酰化p53蛋白含量明显降低(P<0.05),海马组织SOD活力、Bcl-2和Sirt1蛋白含量明显升高(P<0.05)。结论丹酚酸A复合右美托咪定可显著降低脑缺血-再灌注损伤大鼠海马神经元凋亡,其作用可能与Sirt1-p53通路有关。

Objective To investigate the effects of salvianolic acid A combined with dexmedetomidine on neuronal apoptosis and Sirt1-p53 pathway in hippocampus of rats with cerebral ischemia-reperfusion injury. Methods Ninety SD rats, weighing 160-230 g, were randomly divided into sham group(group S), ischemia-reperfusion group(group IR), salvianolic acid A group(group A), dexmedetomidine group(group D), salvianolic acid A combined with dexmedetomidine group(group AD). The middle cerebral artery ischemia-reperfusion injury model was established by thread embolization. The hemodynamics of rats in each group was measured. Morris water maze experiment was used to observe the average escape latency and the number of crossing the platform on the 1^st, 2^nd, 3^rd, 4^th and 5^th day. The neurological deficit scores in each group were compared, the apoptosis of hippocampal neurons was detected by TUNEL method, the activity of SOD was detected by xanthine oxidase method, the content of MDA was detected by barbituric acid sulfide method, the expression of Bcl-2 and Bax protein in hippocampal tissue was detected by immunohistochemistry, and the expression of Sirt1 and acetylated p53 protein in hippocampus was detected by western blot. Results Compared with group S, the average escape latency of rats in group IR, A, D and AD was significantly increased on the 1^st, 2^nd, 3^rd, 4^th and 5^th day(P < 0.05), the number of crossing platformwas significantly reduced(P < 0.05), the levels of HR was significantly decreased(P < 0.05), the levels of CO and MAP were significantly reduced(P < 0.05), the levels of neurological deficit score were significantly increased(P < 0.05) and the percentage of apoptosis, MDA content, Bax and acetylated p53 protein content in hippocampus were significantly increased(P < 0.0 5). SOD activity, Bcl-2 and Sirt1 protein expression in hippocampus were significantly decreased(P < 0.05). Compared with group IR, the average escape latency of group S, A and AD was significantly decreased on the 1^st, 2^nd, 3^rd, 4^th and 5^th day(P < 0.05), the number of crossing platform was significantly increased(P < 0.05), the levels of HR was significantly increased(P < 0.05), the levels of MAP and CO were significantly increased(P < 0.05), the levels of neurological deficit score was significantly reduced(P < 0.05), and the percentage of hippocampal cell apoptosis, MDA content, Bax and acetylated p53 protein content were significantly decreased(P < 0.05). The activity of SOD andthe expression of Bcl-2 and Sirt1 in hippocampus were significantly increased(P < 0.05). Compared with group A and group D, the average escape latency of group AD was significantly reduced on the 1^st, 2^nd, 3^rd, 4^th and 5^th day(P < 0.05), the number of crossing platform was significantly increased(P < 0.05), the level of HR was significantly increased(P < 0.05), the levels of MAP and CO were significantly increased(P < 0.05), the levels of neurological deficit score were significantly reduced(P < 0.05), and the percentage of hippocampal cell apoptosis, MDA content, Bax and acetylated p53 protein were significantly decreased(P < 0.05). SOD activity, Bcl-2 and Sirt1 protein expression in hippocampus were significantly increased(P < 0.05). Conclusion Salvianolic acid A combined with dexmedetomidine can significantly reduce the apoptosis of hippocampal neurons in rats with cerebral ischemia-reperfusion injury, and its effect may be related to Sirt1-p53 pathway.