黄连总生物碱减轻大鼠脑缺血再灌注引起的神经元损伤：基于BDNF-TrkB通路

Total alkaloids from coptis chinensis mitigate neuronal damage induced by cerebral ischemiareperfusion in rats:involvement of the BDNF-TrkB pathway

摘要:

：目的 观察黄连总生物碱对脑缺血再灌注大鼠神经功能损伤后的影响。方法 运用SD大鼠建立大 脑中动脉闭塞缺血（MCAO）模型，将45只健康雄性大鼠随机分为假手术组、模型组、黄连总生物碱（高、中、低浓度） 组，每组9只。予假手术组与模型组大鼠生理盐水灌胃，黄连总生物碱（高、中、低浓度）组采用不同浓度的黄连总生 物碱灌胃。给药7 d后运用Longa的5分法评分标准对各组大鼠神经功能缺损评分，观察海马组织病理学改变及海 马组织超氧化物歧化酶（SOD）的活力、丙二醛（MDA）和还原型谷胱甘肽（GSH）含量变化等情况，采用 Western blotting检测各组大鼠海马区BDNF、TrkB蛋白表达情况。结果 与假手术组比较，模型组的神经功能缺损评分显 著提高（P < 0.05），血清中的SOD活力和GSH含量明显降低（P < 0.05），而MDA含量明显增加（P < 0.05）；海马组织 细胞排列混乱不规则，网状纤维遭到破坏，脑细胞肿胀坏死，形成胶质瘢痕，有明显的核固缩现象；BDNF蛋白、TrkB 蛋白表达量明显减少（P<0.001）。与模型组相比，黄连总生物碱治疗组用药7 d后大鼠神经功能缺损评分均明显降 低（P < 0.05）；海马神经元组织胶质瘢痕明显减小，病变程度得到明显改善；黄连总生物碱各剂量组中的 SOD活力 和GSH含量水平均显著提升（P < 0.05），MDA活力均显著降低（P < 0.05）；且Western blotting检测发现高、中浓度组 BDNF、TrkB 蛋白表达量明显高于模型组（P < 0.05 或 0.01）。结论 黄连总生物碱对海马区神经元细胞的保护作 用，通过上调BDNF和其受体TrkB蛋白表达水平减轻神经元损伤。

Abstract:

Objective To observe the effects of total alkaloids of coptis chinensis on neurological function impairment following cerebral ischemia-reperfusion in rats. Methods A model of middle cerebral artery occlusion (MCAO) was established in 45 healthy male SD rats, which were randomly assigned into sham operation group, model group, and treatment groups with high, medium, and low concentrations of total alkaloids of coptis chinensis, each with 9 rats. The sham operation group and model group rats were handled daily and administered saline intraperitoneally. The treatment groups were given different concentrations of total alkaloids of coptis chinensis via gavage. After 7 days of treatment, the neurological deficit scores of the rats in each group were evaluated using the 5-point scoring system proposed by longa, and the pathological changes in the hippocampal tissue were observed. The activities of superoxide dismutase (SOD), malondialdehyde (MDA), and reduced glutathione (GSH) in the hippocampal tissue were measured, and the expression of Brain-Derived Neurotrophic Factor (BDNF) and Tropomyosin Receptor Kinase B (TrkB) proteins in the hippocampal region was detected by Western blotting. Results Compared with the sham operation group, the neurologic deficit score of the model group was significantly increased (P < 0.05), the activity of SOD and the content of GSH in serum were significantly decreased (P < 0.05), while the content of MDA was significantly increased (P < 0.05). The cells of hippocampus were disordered and irregularly arranged, the reticular fibers were destroyed, the brain cells were swollen and necrotic, and formed glial scar with obvious nuclear pyknosis, and the expression of BDNF protein and TrkB protein were obviously decreased (P < 0.001). Compared with the model group, the neurologic deficit scores of rats in the total alkaloid treatment group were significantly decreased after 7 days (P < 0.05), and the glial scar in the hippocampus was significantly reduced, the activities of SOD and GSH were significantly increased (P < 0.05), and the activities of MDA were significantly decreased (P < 0.05) in each dose group of total alkaloids of coptis chinensis western blotting showed that the expression levels of BDNF and TrkB in the high and middle concentration groups were significantly higher than those in the model group (P < 0.001). Conclusion The protective effect of total alkaloids of rhizoma coptidis on hippocampal neurons can be alleviated by up-regulating the expression of BDNF and its receptor TrkB.