基质金属蛋白酶-9在缺氧后脑损伤中的动态表达

Dynamic expression of matrix metalloproteinase-9 in hypoxic brain injury

目的基质金属蛋白酶-9在早产儿缺氧缺血性性脑损伤中的具体作用机制仍然不是十分明确,本研究拟了解基质金属蛋白酶-9在缺氧大鼠脑组织中的蛋白表达,进而了解基质金属蛋白酶-9对于缺氧之后脑组织修复的具体作用。方法将72只3日龄新生SD大鼠随机分成正常对照组和缺氧组,每组各36只,对正常对照组大鼠不做任何处理,将缺氧组大鼠置于密闭容器中,充以8%氧气+92%氮气的混合气体90 min。分别于造模1、3、7、14、21和28 d后留取脑组织,应用Western blot检测基质金属蛋白酶-9的表达情况。结果缺氧组大鼠脑组织基质金属蛋白酶-9呈现动态表达变化规律,在缺氧早期(缺氧后1 d),基质金属蛋白酶-9变化不明显,从缺氧后3 d开始表达升高,较正常对照组明显增加,至7 d达到高峰,14 d时表达有所降低,21 d和28 d时表达量与正常对照组相当。结论缺氧造成新生大鼠脑损伤时,基质金属蛋白酶-9的表达谱呈现高峰提前以及早期表达量升高的趋势,提示基质金属蛋白酶-9通过剂量的变化对缺氧后脑组织损伤进行了调节作用。

Objective The mechanism of matrix metalloproteinase-9 is still not so clear in hypoxic-ischemia brain injury of preterm infants.This study is designed to investigate the expression profile of matrix metalloproteinase-9 in rats after hypoxia.Then to understand the detailed function of matrix metalloproteinase-9 in brain repair.Methods 72 3-day SD rats were divided into normal control group and hypoxia group randomly with each group having 36 rats.Rats of hypoxia group were put in a closed vessel and be treated with mixed gas which including 8% O2 and 92% N2 for 90 minutes,with no treatment to control group.Brain tissue was obtained in 1 d,3 d,7 d,14 d,21 d and 28 d after hypoxia treatment.Western blot was used to detect the expression of matrix metalloproteinase-9.Results In hypoxia group,matrix metalloproteinase-9 of brain tissue expressed dynamically.Matrix metalloproteinase-9 did not show obvious change 1 day after hypoxia treatment,while it showed increased expression 3 days after hypoxia treatment and reached its peak 7 days after hypoxia treatment.The expression of matrix metalloproteinase-9 decreased 14 days after hypoxia and it reached the same level to normal control group 21 days and 28 days after hypoxia treatment.Conclusion When brain injury happens after hypoxia,matrix metalloproteinase-9 shows an advanced expression peak and a trend of increased expression in early stage.All this indicates that matrix metalloproteinase-9 regulate the injured brain tissue by a change of expression level.