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目的:探讨急性肺损伤大鼠体内基质金属蛋白酶2,9(MMP-2,MMP-9)活性的变化。方法:60只SD大鼠随机分为假手术组(Sham组,n=30)、内毒素组(LPS组,n=30)。LPS组大鼠气管内一次性注入0.3mL含LPS(6mg.kg-1)的生理盐水复制ALI模型,假手术组大鼠则在气管内一次性注入等量生理盐水。两组动物同步于气管内LPS灌注后1、3、7天分别随机处死10只。收集肺泡灌洗液,冰浴匀浆肺组织制备匀浆液,-80℃冻存。Bradford法测定血浆蛋白含量和肺泡灌洗液中蛋白含量,计算肺通透指数;酶谱法测肺组织匀浆液和支气管肺泡灌洗液上清中MMP-2、MMP-9酶活性及免疫组织化学方法检测肺组织MMP-2、MMP-9蛋白表达情况。结果:酶谱法显示:与假手术组相比,LPS组各样品MMP-2活性均有所增加,MMP-2从第1天起持续升高到第7天未见回落;MMP-9活性从第3天开始持续升高至第7天,免疫组化显示MMP-2、MMP-9在LPS组肺组织细胞高表达。结论:MMP-2、MMP-9的活性增强在LPS诱导大鼠ALI发病机制中发挥重要的作用。
Objective: To investigate the changes of matrix metalloproteinase 2, 9 (MMP-2, MMP-9) in rats with acute lung injury. Methods: Sixty Sprague Dawley rats were randomly divided into Sham operation group (n = 30) and LPS group (n = 30). Rats in LPS group were injected with 0.3 mL saline containing LPS (6 mg.kg-1) into the trachea, and ALI model rats were injected intraperitoneally. Two animals were randomly sacrificed on the 1st, 3rd, 7th day after tracheal LPS perfusion respectively. Alveolar lavage fluid was collected, homogenized in ice bath homogenate lung tissue, frozen at -80 ℃. Bradford method for determination of plasma protein content and alveolar lavage fluid protein content, calculate the permeability index of the lung; zymography method to measure lung homogenate and bronchoalveolar lavage fluid supernatant of MMP-2, MMP-9 activity and immune tissue The chemical method was used to detect the expression of MMP-2 and MMP-9 in lung tissue. Results: Zymography showed that compared with the sham operation group, MMP-2 activity increased in all samples of LPS group. MMP-2 increased continuously from day 1 to no change on the 7th day. MMP-9 activity From the third day until the seventh day, the expression of MMP-2 and MMP-9 in the LPS group was significantly higher than that in the LPS group. Conclusion: The enhanced activity of MMP-2 and MMP-9 play an important role in the pathogenesis of ALI induced by LPS in rats.