苦参素对慢性脑缺血大鼠海马CA1区神经元凋亡保护作用的研究

Inhibitory effect of oxymatrine on apoptosis in hippocampal CA1 region of the rats with chronic cerebral ischemia

关键词:  苦参素  脑缺血  海马CA1区  凋亡  氧化应激

Key words:  oxymatrine  cerebral ischemic  hippocampal CA1 region  apoptosis  oxidative stress

摘要:

[目的]研究苦参素对大鼠慢性脑缺血后大脑海马CA1区神经元凋亡的保护作用并探讨其机制。[方法]将100只SD大鼠采用结扎双侧颈总动脉的方法复制慢性脑缺血大鼠模型，设假手术组、模型组和苦参素低[25 mg/（kg·d）]、中[50 mg/（kg·d）]、高[100 mg/（kg·d）]剂量组，各20只，术后第2天开始腹腔注射给药，疗程7 d。通过苏木精-伊红（HE）染色、末端标记（TUNEL）法分别观察海马CA1区神经元形态及凋亡状况；免疫组织化学（IHC）法检测海马B淋巴细胞瘤-2（Bcl-2）、Bcl-2相关X蛋白（Bax）蛋白表达；蛋白免疫印迹（Western blot）法检测半胱氨酸天冬氨酸蛋白酶-3（Caspase-3）、核因子-κB（NF-κB）蛋白表达；生化分析海马区氧化酶活性和丙二醛（MDA）含量；测定海马组织炎症细胞因子含量。[结果]与模型组比较，苦参素中、高剂量组慢性脑缺血大鼠海马CA1区神经元形态结构变化和凋亡状况均明显改善，凋亡指数（AI）显著降低（P<0.01），海马区Bcl-2表达上调、Bax表达下调且Bcl-2/Bax比值显著提高（P<0.05或P<0.01），Caspase-3、NF-κB蛋白表达均显著下调（P<0.05或P<0.01），抗氧化酶[超氧化物歧化酶（SOD）、过氧化氢酶（CAT）]活性显著升高且MDA含量显著降低（P<0.05或P<0.01）；炎症细胞因子[白介素-1β（IL-1β）、白介素-6（IL-6）、肿瘤坏死因子（TNF-α）]含量均显著降低（P<0.05或P<0.01）。[结论]苦参素具有抑制慢性脑缺血大鼠海马CA1区神经元凋亡的药理学作用，其机制可能与苦参素调节凋亡相关蛋白表达以及提高氧自由基清除能力、抑制炎症反应有关。

Abstract:

[Objective] To study the inhibitory effect of oxymatrine on apoptosis in hippocampal CA1 region of the rats with chronic cerebral ischemia.[Methods] The chronic cerebral ischemia model was established by ligating bilateral common carotid artery, setting sham operating group, model group and oxymatrine low, medium, high-dose (25, 50, 100 mg/kg) groups, n=20. The drugs were given by intraperitoneal injection from the second day after operation for 7 d. The morphological changes of neurons in hippocampus CA1 region were observed by HE Staining, the cell apoptosis were observed after TUNEL staining; the expression of Bcl-2 and Bax were exzamed by IHC, the expression of Caspase-3, NF-κB were determined by Western blotting, the activity of antioxidant enzymes and malondialdehyde (MDA) in Hippocampus tissue were measured by biochemical analysis.[Results] Compared with model group, both of the hippocampal CA1 neuronal pathological changes and apoptosis were significantly improved, the apoptosis index (AI) were significantly decreased (P<0.01). The expression of Bcl-2 were significantly up-regulated and the expression of Bax were down-regulated, increased the Bcl-2/Bax ratio (P<0.05 or P<0.01). The activity of caspase-3 and NF-κB were significantly decreased (P<0.05 or P<0.01). The activity of antioxidant enzymes (SOD, CAT) activity were significantly improved and the content of MDA were significantly decreased (P<0.05 or P<0.01).[Conclusion] Oxymatrine has a pharmacological effect of inhibiting apoptosis of hippocampal CA1 region in rats with chronic cerebral ischemia, which may be related to the regulation of oxymatrine apoptosis-related protein expression and reduce oxidative stress damage.