依达拉奉对缺氧缺血性脑损伤新生大鼠脑组织MMP-9的影响

Effect of edaravone on the expression of matrix metalloproteinase-9(MMP-9)after hypoxic-ischemic brain damage in neonatal rats

目的观察依达拉奉对缺氧缺血性脑损伤(HIBD)新生大鼠脑组织基质金属蛋白酶-9(MMP-9)表达的影响,探讨依达拉奉对新生大鼠HIBD的保护作用。方法随机将7日龄Wistar大鼠108只分为3组(假手术组、HIBD组、依达拉奉治疗组),每组36只。根据造模后处死时间,各组又分6个亚组:6h、1d、2d、3d、5d、7d组,每亚组各6只。通过结扎左颈总动脉和吸入8%低氧混合气制备缺氧缺血性脑损伤(HIBD)动物模型。假手术组动物只分离左颈总动脉,不结扎,亦不做低氧处理。治疗组于缺氧缺血后即刻给予腹腔注射生理盐水稀释的依达拉奉注射液(2mg/kg,每24h1次,连续5d。HIBD组和假手术对照组腹腔注射等量生理盐水)。分别于相应时点断头处死各组动物,取脑,采用干湿质量法测定大鼠脑组织含水量,采用逆转录聚合酶链反应(RT-PCR)技术检测MMP-9mRNA的表达情况。结果 HIBD组大鼠脑组织含水量在缺氧缺血后逐渐上升,2d时达到高峰,各时间点均高于假手术组(P<0.05)。同时,MMP-9mRNA表达量与脑含水量呈相应逐渐上升改变,MMP-9mRNA表达量与脑组织含水量呈正相关。依达拉奉治疗组与HIBD组相比,脑组织含水量明显下降(P<0.05),MMP-9mRNA表达量显著下调(P<0.05)。结论 MMP-9参与了HIBD脑水肿的发生发展过程,依达拉奉可降低脑组织MMP-9的表达,从而减轻脑水肿,这可能是其脑保护作用机制之一。

Objective To investigate the effect of edaravone on the expression of matrix metalloproteinase-9（MMP-9） mRNA after hypoxic-ischemic brain damage（HIBD） in neonatal rats.Methods A total of 108 neonatal 7-day-old Wistar rats were randomly divided into 3 groups（n=36 in each group）：sham-operation group,HIBD group and Edaravone-treatment group.Each group was divided into six sub-groups（n=6 in each sub-group） based on different time points after HIBD（6h,1d,2d,3d,5d,7d）.HIBD rat models were established by ligating the left common carotid artery,followed by exposure to 8% oxygen and 92% nitrogen for 2 hours in the HIBD group and Edaravone-treatment group.The sham-operation group and the HIBD group were sham-operated and treated with normal sodium injection;Edaravone-treated group were treated with Edaravone 2mg/kg every 24 hours in 5 days.Animals were sacrificed at different time points.Changes of brain water content were determined by dry-wet weight method.And the expression of MMP-9 mRNA was measured by reverse transcriptase-polymerase chain reaction（RT-PCR） technique.Results HIBD group showed an upward trend in brain water content after HIBD,peak at 2d,each time point were higher than that of the sham-operated group（P0.05）.Meanwhile,MMP-9 mRNA expression and brain water content showed the same trend,indicating that the expression of MMP-9 mRNA and brain tissue water content were correlated positively.The levels of brain water content and MMP-9 mRNA expression in Edaravone-treatment group were significantly lower than HIBD group at each time point（P0.05）.Conclusions MMP-9 plays an important role in the development process of cerebral edema after HIBD.Edaravone can protect brain by reducing the expression of MMP-9.