延龄草总皂苷对2-VO模型大鼠认知功能及神经血管单元的作用

Effects of total saponins of Trillium tschonoskii Maxim on cognitive function and neurovascular unit in 2-VO model rats

目的观察延龄草总皂苷(TST)对大鼠的血管性认知障碍及其神经血管单元(NVU)和神经环路完整性的作用。方法将48只雄性SD大鼠随机分为假手术组、模型组、TST组及多奈哌齐组,每组12只。除假手术组外,其他3组大鼠均采用双侧颈总动脉结扎(2-VO)法建立脑缺血后认知障碍模型。造模后,TST组给予TST100mg/kg灌胃,多奈哌齐组给予盐酸多奈哌齐0.45mg/kg灌胃,对照组及模型组给予同体积的生理盐水,1次/d,连续28d。采用水迷宫实验检测各组大鼠的认知功能;HE、尼氏染色观察大鼠脑组织病理改变;免疫组织化学染色观察大鼠海马突触核蛋白(SYN)的表达情况;高尔基染色观察海马神经元树突棘的变化;Westernblotting检测各组大鼠海马组织白细胞介素(IL)-1β、IL-10、血管内皮生长因子A(VEGFA)、突触后致密蛋白95(PSD95)和生长关联蛋白43(GAP43)表达水平。结果水迷宫实验结果显示,与假手术组比较,模型组大鼠的逃避潜伏期延长(P<0.05),穿越平台次数和在目标象限的停留时间比均减少(P<0.05);与模型组比较,TST组和多奈哌齐组逃避潜伏期缩短(P<0.01),穿越平台次数和在目标象限的停留时间比增多(P<0.05)。与假手术组比较,模型组海马CA1区神经元、尼氏小体、树突棘数量和SYN表达量减少(P<0.05);与模型组比较,TST组和多奈哌齐组神经元、尼氏小体、树突棘数量和SYN表达量增多(P<0.05)。Westernblotting结果显示,与假手术组比较,模型组大鼠海马组织IL-1β、VEGFA表达水平升高(P<0.05),PSD95、GAP43表达水平降低(P<0.01);与模型组比较,TST组和多奈哌齐组IL-1β表达水平均降低(P<0.05),VEGFA、IL-10、GAP43表达水平均升高(P<0.05)。结论TST可能通过促进突触可塑性和NVU重塑减轻2-VO模型大鼠的认知障碍,有望用于卒中的治疗。

Objective To observe the effects of total saponins of Trillium tschonoskii Maxim(TST)on vascular cognitive impairment(VCI),neurovascular units(NVUs),and neural circuit integrity in rats.Methods Forty-eight male Sprague-Dawley(SD)rats were randomly divided into sham-operated group,model group,TST group(intragastric administration,100 mg/kg),and donepezil group(intragastric administration,0.45 mg/kg),and then subjected to ischemic stroke by 2-VO method(bilateral common carotid artery ligation)or sham surgery.After 28 days of intragastric administration,Mirros water maze test was performed to evaluate the spatial learning and memory abilities of rats in each group.HE and Nissl staining were used to observe the pathological changes of brain tissue in rats.The expression of synuclein(SYN)in rat hippocampus was observed by immunohistochemical staining.Changes in dendritic spines in rat's hippocampal neurons were observed by Golgi staining.Western blotting was used to detect the expression levels of IL-1β,IL-10,vascular endothelial growth factor A(VEGFA),postsynaptic density protein 95(PSD95),and growth associated protein 43(GAP43)in rat's hippocampus in each group.Results In Mirros water maze test,rats in model group showed significant prolonged escape latency(P<0.05),and a significant reduction in the number of crossing platforms and the percentage of activity time in the target quadrant(P<0.05)than those in sham-operated group;while rats in TST group and donepezil group showed significant shortened escape latency(P<0.01),and significant increase of the number of times of crossing platforms and the percentage of activity time in the target quadrant(P<0.05)than those in model group.Compared of sham-operated group,model group showed a decrease in the expression of SYN and the number of neurons,Nissl bodies,and dendritic spines in the CA1 region of the hippocampus(P<0.05).Compared with model group,TST group and donepezil group showed an increase in the expression of SYN and the number of neurons,Nissl bodies,and dendritic spines in the CA1 region of the hippocampus(P<0.05).Western blotting showed a significant increase in the expression of IL-1βand VEGF(P<0.05),and a decrease in the expression of IL-10,PSD95,and GAP43(P<0.01)in rat's hippocampus of model group than those in sham-operated group.Compared with model group,TST group and donepezil group showed a significant decrease in the expression of IL-1β(P<0.05),and an increase in the expression of VEGFA,IL-10,and GAP43(P<0.05).Conclusions TST could alleviate cognitive impairment through promoting synaptic plasticity and neurovascular unit remodeling in 2-VO model rats,suggesting its significance as a potential drug for apoplexy.