注射用丹参多酚酸对大鼠脑缺血再灌注损伤的保护作用及机制研究

Protective Effect and Mechanism of Salvia Polyphenolic Acid for Injection on Cerebral Ischemiareperfusion Injury in Rats

目的探讨注射用丹参多酚酸(SAFI)对大鼠脑缺血再灌注损伤的保护作用及机制。方法将100只SD大鼠随机分为假手术组、模型组及丹参多酚酸低、中、高剂量组(5、10、20 mg·kg^(-1)),每组20只。采用改良线栓法复制大脑中动脉闭塞再灌注(MCAO/R)大鼠模型。于MCAO/R手术前按照上述剂量腹腔注射给药,每日1次,连续给药3 d;末次给药1 h后,进行MCAO/R模型复制。采用Longa五级评分方法进行神经功能缺失评分;采用TTC染色后测量脑梗塞体积;ELISA法检测血清中氧化应激指标NADPH氧化酶(NOX)、4-羟基壬烯醛(4-HNE)、8-羟基脱氧鸟苷(8-OHd G)及炎症反应指标单核细胞趋化蛋白1(MCP-1)、肿瘤坏死因子α(TNF-α)、白细胞介素1β(IL-1β)、IL-18、IL-6、细胞间黏附分子1(ICAM-1)的水平;HE及尼氏染色法观察脑组织病理损伤情况;TUNEL染色法检测脑组织神经元细胞凋亡情况;免疫荧光法测定大鼠脑组织中胶质纤维酸性蛋白(GFAP)的表达情况;Western Blot法检测脑组织中NLRP3、Caspase1蛋白表达情况。结果与假手术组比较,模型组大鼠神经功能缺损评分显著升高(P<0.01),脑梗死体积显著增加(P<0.01),脑组织病理损伤明显,神经元密度显著降低(P<0.01),皮层细胞凋亡率显著升高(P<0.01);血清NOX、4-HNE、8-OHd G、MCP-1、TNF-α、IL-1β、IL-18、IL-6、ICAM-1水平均显著升高(P<0.05,P<0.01);脑组织中GFAP、NLRP3、Caspase1蛋白表达显著上调(P<0.01)。与模型组比较,SAFI中、高剂量组大鼠的神经功能缺失评分显著降低(P<0.01),脑梗死体积显著缩小(P<0.01),神经元损伤有不同程度好转,神经元密度显著增加(P<0.05,P<0.01),皮层细胞凋亡率显著降低(P<0.01);血清NOX、4-HNE、8-OHd G、MCP-1、TNF-α、IL-1β、IL-18、IL-6、ICAM-1水平明显降低(P<0.05,P<0.01);脑组织中GFAP、NLRP3、Caspase1蛋白表达显著下调(P<0.01)。结论SAFI预防性给药可明显降低脑缺血再灌注损伤大鼠的炎症反应和氧化应激水平,改善脑组织病理损伤,发挥神经保护作用,其机制可能与抑制星型胶质细胞活化及NLRP3/Caspase-1通路激活有关。

Objective To investigate the neuroprotective effect and mechanism of salvia polyphenolic acid for injection(SAFI)on cerebral ischemia-reperfusion injury in rats.Methods A total of 100 SD rats were randomly divided into sham surgery group,model group,low-,medium-and high-dose(5,10,20 mg·kg^(-1))salvia polyphenolic acid groups,with 20 rats in each group.After being continuously administrated by intraperitoneal injection of SAFI once daily for three days,the rat model of middle cerebral artery occlusion/reperfusion(MCAO/R)was established using the thread embolization method at 1 hour after the last administration.The neurological deficit of rats was evaluated by Zea Longa score.The cerebral infarction volume was detected by 2,3,5-triphenyltetrazolium chloride(TTC)staining.The levels of serum NADPH oxidase(NOX),4-hydroxynonanal(4-HNE),8-hydroxydeoxyguanosine(8-OHdG),monocyte chemoattractant protein-1(MCP-1),tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),interleukin-18(IL-18),interleukin-6(IL-6),and intercellular adhesion molecule-1(ICAM-1)were detected by ELISA kits.Hematoxylin-eosin(HE)staining and Nissl staining were used to observe the pathological changes of brain tissue and the morphology of neurons.The apoptosis of neuronal cells in brain tissue was detected by TUNEL.Immunofluorescence staining was used to detect the expression level of glial fibrillary acidic protein(GFAP)in brain tissue.Western Blot was used to detect the protein expression of NLRP3 and Caspase1 in brain tissue.Results Compared with the sham surgery group,neurological deficit scores in model group increased remarkably(P<0.01).The cerebral infarction volume increased significantly(P<0.01).Serious pathological damage of brain was observed,and neuronal density decreased significantly(P<0.01).The apoptosis rate of cortical cells increased obviously(P<0.01).The levels of serum NOX,4-HNE,8-OHdG,MCP-1,TNF-α,IL-1β,IL-18,IL-6 and ICAM-1 increased significantly(P<0.05,P<0.01).The protein expression of GFAP,NLRP3 and Caspase1 in brain significantly upregulated(P<0.01).Compared with the model group,neurological deficit scores in medium-and high-dose SAFI groups decreased remarkably(P<0.01).The cerebral infarction volume decreased significantly(P<0.01).Neuronal damage was ameliorated to varying degrees,and neuronal density increased significantly(P<0.05,P<0.01).The apoptosis rate of cortical cells decreased obviously(P<0.01).The levels of serum NOX,4-HNE,8-OHdG,MCP-1,TNF-α,IL-1β,IL-18,IL-6 and ICAM-1 decreased significantly(P<0.05,P<0.01).The protein expression of GFAP,NLRP3 and Caspase1 in brain significantly downregulated(P<0.01).Conclusion SAFI has a protective effect on MCAO/R rats,which can significantly reduce oxidative stress and inflammatory responses,thereby reducing pathological damage and apoptosis of brain tissue.Its mechanism may be related to the inhibition of NLRP3/Caspase-1 signaling pathway and astrocyte activation.