β-七叶皂苷钠对急性创伤性脑损伤大鼠脑保护作用研究

EFFECTS OFβ-SODIUM AESCINATE ON BRAIN PROTECTION IN RATS WITH ACUTE TRAUMATIC BRAIN INJURY

目的研究β-七叶皂苷钠对急性创伤性脑损伤模型大鼠脑保护作用。方法选取健康成年SD大鼠45例,随机分为3组:假手术组、模型组、β-七叶皂苷钠治疗组,每组15例。模型组和β-七叶皂苷钠治疗组大鼠固定在Freeny’s自由落体架构建大鼠颅脑损伤模型,假手术组只做头部窗口不予打击。模型构建后,治疗组灌胃剂量为30 mg/kg的β-七叶皂苷钠,假手术组和模型组灌胃等体积容量的生理盐水,治疗每日1次,连续14 d,分别在治疗第1天、第7天和第14天用mNSS评分系统评估各组大鼠的神经功能;术后9~13 d进行Morris水迷宫测试,记录各组大鼠逃避潜伏期、目标象限内的穿台次数和停留时间;术后15 d取大鼠的脑组织进行免疫组化染色和TUNEL染色,分析脑源性神经营养因子(BDNF)和NGF的表达及细胞凋亡;Western blot检测大鼠脑组织中核因子κB(NF-κB)、基质金属蛋白酶-9(MMP-9)、血管内皮生长因子(VEGF)、B淋巴细胞瘤-2基因(Bcl-2)、Bad和cleaved-caspase-3蛋白表达量。结果随着β-七叶皂苷钠治疗周期的延长,大鼠的神经功能和学习认知功能明显得到恢复和改善。对各组大鼠脑组织水含量检测显示,β-七叶皂苷钠治疗后,大鼠脑组织水含量明显降低(P<0.05);免疫组化染色结果显示β-七叶皂苷钠能够促进BDNF和NGF的表达(P<0.05);TUNEL染色分析发现,与模型组比较,β-七叶皂苷钠治疗能够明显降低大鼠脑组织中凋亡细胞比例,差异有统计学意义(P<0.05);Western blot蛋白分析结果显示,与模型组比较,β-七叶皂苷钠治疗组大鼠脑组织中NF-κB、MMP-9、VEGF及抑凋亡Bcl-2蛋白的表达量明显增加,促凋亡蛋白Bad和cleaved-caspase-3蛋白的表达明显受到抑制,差异有统计学意义(P<0.05)。结论β-七叶皂苷钠能通过激活NF-κB信号通路,上调MMP-9和VEGF蛋白表达,促进细胞增殖和血管生长,抑制脑组织细胞凋亡,保护脑损伤大鼠神经功能。

Objective To study the effects ofβ-sodium aescinate on brain protection in rats with acute traumatic brain injury.Methods Forty-five healthy adult SD rats were randomly divided into sham operation group,model group andβ-sodium aescinate treatment group,with 15 rats in each group.Model group andβ-sodium aescinate treatment group were fixed in the Freeny’s free fall frame to construct a rat model of brain injury,and sham operation group was only made head window without hitting.After model construction,treatment group was intragastrically administrated a dose of 30 mg/kg ofβ-sodium aescinate,and sham operation group and model group were intragastrically administered the same volume of normal saline once a day for 14 d,and the neurological function of each group was evaluated by mNSS scoring system on 1 st d,7 th d and 14 th d of treatment.Morris water maze test was performed at 9 to 13 d after operation,and the escape latency and platform-trough frequency and residence time in the target quadrant were recorded in each group.The brain tissues of rats were taken at 15 d after operation for immunohistochemical staining and TUNEL staining,and the expressions of BDNF and NGF and the apoptosis were analyzed.Western blot was used to detect the protein expression levels of NF-κB,MMP-9,VEGF,Bcl-2,Bad and cleaved-caspase-3 in brain tissues of rats.Results With the prolongation of treatment cycle ofβ-sodium aescinate,the neurological function and cognitive function of rats were significantly restored and improved.The water content in brain tissues in each group showed that the water content in brain tissues of rats was significantly decreased afterβ-sodium aescinate treatment(P<0.05).The results of immunohistochemical staining showed thatβ-sodium aescinate couldpromote the expression levels of BDNF and NGF(P<0.05).TUNEL staining analysis showed that compared with model group,β-sodium aescinate treatment could significantly reduce the proportion of apoptotic cells in rat brain tissues(P<0.05).Western blot protein analysis showed that compared with model group,the protein expression levels of NF-κB,MMP-9,VEGF and anti-apoptotic Bcl-2 in the brain tissues were significantly increased inβ-sodium aescinate treatment group,and the protein expression levels of pro-apoptotic proteins Bad and cleaved-caspase-3 were significantly inhibited(P<0.05).Conclusionβ-sodium aescinate can up-regulate the expression levels of MMP-9 and VEGF by activating NF-κB signaling pathway,promote cell proliferation and angiogenesis,inhibit brain cell apoptosis and protect neurological function in rats with brain injury.