AIM: To study the effects of hypoxia, hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 (MMP-2) in hepatic stellate cells (HSC). METHODS: The expressions of MMP-2, tissue inhibitor o...AIM: To study the effects of hypoxia, hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 (MMP-2) in hepatic stellate cells (HSC). METHODS: The expressions of MMP-2, tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) and membrane type matrix metalloproteinase-1 (MT1-MMP) in cultured rat HSC were detected by immunocytochemistry (ICC) and in situ hybridization (ISH). The contents of MMP-2 and TIMP-2 in culture supernatant were detected with ELISA and the activity of MMP-2 in supernatant was revealed by zymography. RESULTS: In the situation of hypoxia for 12h, the expression of MMP-2 protein was enhanced (hypoxia group positive indexes: 5.7 +/- 2.0, n=10; control: 3.2 +/- 1.0, n = 7; P【0.05), while TIMP-2 protein was decreased in HSC (hypoxia group positive indexes: 2.5 +/- 0.7, n = 10; control: 3.6 +/- 1.0, n = 7; P 【 0.05), and the activity (total A) of MMP-2 in supernatant declined obviously (hypoxia group: 7.334 +/- 1.922, n = 9; control: 17.277 +/- 7.424, n = 11; P 【 0.01). Compared the varied duration of hypoxia, the changes of expressions including mRNA and protein level as well as activity of MMP-2 were most notable in 6h group. The highest value(A(hypoxia)-A(control)) of the protein and the most intense signal of mRNA were in the period of hypoxia for 6h, along with the lowest activity of MMP-2. In the situation of hyperoxia for 12h, the contents (A(450)) of MMP-2 and TIMP-2 in supernatant were both higher than those in the control, especially the TIMP-2 (hyperoxia group: 0.0499 +/- 0.0144, n = 16; control: 0.0219 +/- 0.0098, n = 14; P 【 0.01), and so was the activity of MMP-2 (hyperoxia group: 5.252 +/- 0.771, n = 14; control: 4.304 +/- 1.083, n = 12; P 【 0.05), and the expression of MT1-MMP was increased. CONCLUSION: HSC is sensitive to the oxygen, hypoxia enhances the expression of MMP-2 and the effect is more marked at the early stage; hyperoxia mainly raises the activity of MMP-2.展开更多
目的:探讨抑制哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路在高体积分数氧(高氧)致SD幼鼠肺损伤时对磷酸化AKT1(p-AKT1)分子的影响和意义。方法:72只SD幼鼠(3周龄)随机分为空气+生理盐水组、高氧+生理盐水组...目的:探讨抑制哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路在高体积分数氧(高氧)致SD幼鼠肺损伤时对磷酸化AKT1(p-AKT1)分子的影响和意义。方法:72只SD幼鼠(3周龄)随机分为空气+生理盐水组、高氧+生理盐水组、高氧+OSI-027组及高氧+雷帕霉素组(n=18),分别构建动物模型。高氧选择90%氧气持续干预,生理盐水、OSI-027和雷帕霉素干预分别在观察期第1、3、6、8、10和13天时经腹腔注射给药。在造模第3、7和14天时取各组幼鼠进行体重测量、肺湿干重比(wet/drg weight ratio,W/D)计算、肺组织病理学检查、肺泡间隔宽度测定和肺损伤评分,肺组织免疫组化和Western blot检测磷酸化S6K1(p-S6K1)和p-AKT1的分布与水平。结果:与空气组比较,高氧组幼鼠体重明显下降(P<0.05),肺损伤急性期肺W/D增高(P<0.05),肺泡间隔宽度及肺损伤评分明显增加(P<0.05),肺组织p-S6K1阳性细胞增多(P<0.05),肺组织p-AKT1阳性细胞减少(P<0.05),p-S6K1蛋白显著升高(P<0.01),p-AKT1蛋白明显减低(P<0.01);与高氧组比较,高氧+OSI-027组的肺组织损伤减轻,肺组织p-S6K1阳性细胞减少(P<0.05),p-AKT1阳性细胞增多(P<0.05),p-S6K1蛋白水平显著降低(P<0.05),p-AKT1蛋白水平增加(P<0.05);高氧+雷帕霉素组的肺损伤进一步加重(P<0.05),p-S6K1阳性细胞减少(P<0.05),p-AKT1阳性细胞增加(P<0.05),p-S6K1蛋白水平显著降低(P<0.05),p-AKT1蛋白水平显著增加(P<0.05)。与高氧+雷帕霉素组比较,高氧+OSI-027组的肺组织损伤减轻(P<0.05),肺组织p-AKT1阳性细胞减少(P<0.05),p-AKT1蛋白水平降低(P<0.05)。结论:p-AKT1参与了高氧肺损伤的发生发展,其调控机制可能与抑制mTOR信号通路的活化有关。高氧肺损伤时,p-AKT1蛋白水平下降,mTOR抑制剂能增加p-AKT1蛋白水平,但只有mTORC1/2双重抑制剂OSI-027能减轻高氧所致SD幼鼠的肺损伤及纤维化。展开更多
基金Supported by the Scientific Research Fund for Doctorate Education,State Educational Commission,No.9837
文摘AIM: To study the effects of hypoxia, hyperoxia on the regulation of expression and activity of matrix metalloproteinase-2 (MMP-2) in hepatic stellate cells (HSC). METHODS: The expressions of MMP-2, tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) and membrane type matrix metalloproteinase-1 (MT1-MMP) in cultured rat HSC were detected by immunocytochemistry (ICC) and in situ hybridization (ISH). The contents of MMP-2 and TIMP-2 in culture supernatant were detected with ELISA and the activity of MMP-2 in supernatant was revealed by zymography. RESULTS: In the situation of hypoxia for 12h, the expression of MMP-2 protein was enhanced (hypoxia group positive indexes: 5.7 +/- 2.0, n=10; control: 3.2 +/- 1.0, n = 7; P【0.05), while TIMP-2 protein was decreased in HSC (hypoxia group positive indexes: 2.5 +/- 0.7, n = 10; control: 3.6 +/- 1.0, n = 7; P 【 0.05), and the activity (total A) of MMP-2 in supernatant declined obviously (hypoxia group: 7.334 +/- 1.922, n = 9; control: 17.277 +/- 7.424, n = 11; P 【 0.01). Compared the varied duration of hypoxia, the changes of expressions including mRNA and protein level as well as activity of MMP-2 were most notable in 6h group. The highest value(A(hypoxia)-A(control)) of the protein and the most intense signal of mRNA were in the period of hypoxia for 6h, along with the lowest activity of MMP-2. In the situation of hyperoxia for 12h, the contents (A(450)) of MMP-2 and TIMP-2 in supernatant were both higher than those in the control, especially the TIMP-2 (hyperoxia group: 0.0499 +/- 0.0144, n = 16; control: 0.0219 +/- 0.0098, n = 14; P 【 0.01), and so was the activity of MMP-2 (hyperoxia group: 5.252 +/- 0.771, n = 14; control: 4.304 +/- 1.083, n = 12; P 【 0.05), and the expression of MT1-MMP was increased. CONCLUSION: HSC is sensitive to the oxygen, hypoxia enhances the expression of MMP-2 and the effect is more marked at the early stage; hyperoxia mainly raises the activity of MMP-2.
