二氢丹参酮Ⅰ灌胃对急性缺血性脑卒中大鼠神经功能改善作用及其机制

Neuroprotective effect and mechanism of intragastric administration of dihydrotanshinoneⅠon acute ischemic stroke rats

目的探讨二氢丹参酮Ⅰ(DT)灌胃对急性缺血性脑卒中大鼠神经功能的改善作用及其机制。方法将50只SD大鼠随机分为假手术组、模型组以及DT低、中、高剂量组。采用线栓法制备大鼠MCAO模型,假手术组仅分离血管,不进行插栓处理。造模后24 h,DT低、中、高剂量组分别给予1.67、5、15 mg/kg DT溶液灌胃,假手术组和模型组给予等量含2%DMSO的生理盐水灌胃,每天1次,连续7 d。造模24 h后和给药7 d后,采用Zea-Longa五分制评分法对大鼠进行神经行为学评分;采用TTC染色测算脑梗死体积;造模后和给药7 d后使用激光散斑血流仪检测大鼠缺血侧局部脑血流灌注量;HE染色观察缺血侧脑组织海马区的病理形态;Western blotting法检测缺血侧脑组织血管新生相关蛋白血管内皮生成因子(VEGF)、CD31、缺氧诱导因子1α(HIF-1α)表达。结果模型组大鼠神经行为学评分及脑梗死体积大于假手术组(P均<0.01),缺血侧脑血流灌注量变化率低于假手术组(P<0.01);与模型组比较,DT中、高剂量给药组神经行为学评分降低,脑梗死体积减小,缺血侧脑血流灌注量增加(P均<0.05),其中高剂量组神经行为学评分、脑梗死体积低于低剂量组,脑血流灌注量高于低剂量组(P均<0.05)。与假手术组比较,模型组大鼠缺血侧海马区细胞排列紊乱,细胞肿胀破裂,细胞核固缩,给药7 d后,DT各剂量组大鼠海马区细胞状态均有不同程度的改善,其中高剂量组改善最为明显。与假手术组比较,大鼠缺血侧脑组织中VEGF、HIF-1α表达增加、CD31表达下降(P均<0.01),与模型组比较,DT中、高剂量组VEGF、CD31、HIF1α表达显著增加(P均<0.01),DT高剂量组显著高于低剂量组(P均<0.01)。结论DT可改善急性缺血性脑卒中大鼠的神经功能,缩小脑梗死体积,改善局部脑血流灌注,具有促进缺血后血管生成和神经保护作用,其机制可能与促进HIF-1α表达有关。

Objective To investigate the neuroprotective effect of intragastric administration of dihydrotanshinoneⅠ(DT)on acute ischemic stroke rats and its mechanism.Methods Fifty SD rats were randomly divided into the sham operation group,model group and low-dose,medium-dose and high-dose DT groups.The rat models of MCAO were prepared by thread plug method.In the sham operation group,only blood vessels were separated without plug treatment.At 24 h after modeling,the drug was given intragastrically,once a day,for 7 consecutive days.Rats in the low-dose,medium-dose and high-dose DT groups were given 1.67,5,and 15 mg/kg DT solution,respectively,and rats in the sham operation group and model group were given the same amount of normal saline containing 2%DMSO.At 24 h after modeling and 7 d after administration,neurobehavioral scores of the rats were performed by Zea-Longa five-point scale.TTC staining was used to measure cerebral infarction volume.The amount of local cerebral blood perfusion on the ischemic side of rats was detected by laser specular flow meter after modeling and 7 days after administration.HE staining was used to observe the pathological morphology of the hippocampus of ischemic side brain tissues.The expression levels of vascular endothelial growth factor(VEGF),CD31 and(HIF-1α)were detected by Western blotting.Results The neurobehavioral scores and cerebral infarction volume of rats in the model group were significantly higher than those in the sham operation group(all P<0.01),the change rate of ischemic cerebral blood perfusion volume was significantly lower than that of sham operation group(P<0.01).Compared with the model group,the neurobehavioral scores,cerebral infarction volume and cerebral blood perfusion volume of ischemic side significantly decreased in the medium-dose and high-dose DT groups(all P<0.05),the neurobehavioral score and cerebral infarction volume in the high-dose DT group were significantly lower than those in the low-dose DT group(both P<0.05),but cerebral blood perfusion volume was significantly higher than that in the low-dose DT group(P<0.05).Compared with the sham operation group,the model group showed disordered cell arrangement,cell swelling and rupture,and nuclear pyretosis in the ischemic hippocampal region of rats.After 7 days of administration,the cell state in the hippocampal region of rats in all DT groups was improved to varying degrees,with the most obvious improvement in the high-dose group.Compared with the sham operation group,the expression levels of VEGF and HIF-1αincreased and the expression level of CD31 decreased(all P<0.01).Compared with model group,the expression levels of VEGF,CD31 and HIF-1αsignificantly increased in the medium-dose and high-dose DT groups(all P<0.01),and those in the high-dose DT group were significantly higher than those in the low-dose DT group(all P<0.01).Conclusion DT can improve the nerve function of acute ischemic stroke rats,reduce the volume of cerebral infarction,improve local cerebral blood flow,promote the angiogenesis and has neuroprotective effect after ischemia;the mechanism may be related to the promotion of HIF-1αexpression.