科研动态

为研究无乳链球菌（Streptococcus agalactiae，S. agalactiae）作用奶牛乳腺成纤维细胞（BMFBs）后对MMPs/TIMPs与uPA系统（uPA/PAI-1）表达的影响，以进一步阐明MMPs/TIMPs与uPA系统在调控细胞外基质（ECM）代谢的作用，将107 cfu/mL热灭活S. agalactiae菌液作用于BMFBs，在作用后不同时间点（6、12、24、48 h）通过RT-qPCR和Western Blot检测MMP-2、MMP-9、TIMP-1、TIMP-2、uPA、PAI-1 mRNA转录水平和相应蛋白表达水平，并用明胶酶谱法检测MMP-2、MMP-9的酶活性。结果显示：热灭活S. agalactiae作用后，MMP-9、TIMP-2、uPA、PAI-1 mRNA转录水平均有不同程度下降趋势，但MMP-2 mRNA水平上调，TIMP-1 mRNA水平呈先上升后下降趋势；明胶酶谱法检测MMP-2的酶活性较MMP-9明显，二者均在作用6 h、48 h活性最强；MMP-2和MMP-9蛋白表达水平与对照组相比主要呈先升高后下降趋势，但在作用后期MMP-2蛋白表达又出现了回升趋势；TIMP-1蛋白水平与对照组相比主要呈先下降后上升趋势，在作用前期与MMP-9蛋白表达相反，TIMP-2蛋白表达与对照组相比呈上升趋势；uPA和PAI-1蛋白水平与对照组相比均呈先降低后升高再降低趋势，均在24 h达到峰值，随后呈下降趋势。研究表明，热灭活S. agalactiae菌液可诱导BMFBs中MMPs/TIMPs表达，影响uPA系统参与调控MMPs的表达及活性。

The Effect of Inactivated S. agalactiae on Metalloproteinase and uPA System Expression in BMFBs

In order to study the effect of Streptococcus agalactiae（S. agalactiae）on bovine mammary fibroblasts（BMFBs）and subsequently on the expression of MMPs/TIMPs and uPA system（uPA/PAI-1），and to further clarify the role of MMPs/TIMPs and uPA system in regulating extracellular matrix（ECM）metabolism，107cfu/mL heat-inactivated S. agalactiae was acted on BMFBs，the levels of MMP-2，MMP-9，TIMP-1，TIMP-2，uPA，PAI-1 mRNA transcription and corresponding protein expression were detected by RT-qPCR and Western Blot at different time points（6，12，24 and 48 h），then the enzymatic activities of MMP-2 and MMP-9 were detected by gelatin zymography. The results showed that after the reaction of heat-inactivated S. agalactiae，the level of transcription of MMP-9，TIMP-2，uPA and PAI-1 mRNA trended to reduce to different extent，except that of MMP-2 mRNA，and that of TIMP-1 mRNA increased firstly and then decreased；the enzymatic activity of MMP-2 was more obvious than that of MMP-9 as detected by gelatin zymography，both of which were strongest in 6 and 8 h after reaction；as compared with the control group，the level of protein expression of MMP-2 and MMP-9 trended to increase prior to decrease，but the protein expression of MMP-2 rose again at later stage；as compared to the control group，the level of protein of TIMP-1 showed a trend of decreasing prior to rising，which was contrary to that of MMP-9 at early stage，and TIMP-2 trended to increase；the levels of protein of uPA and PAI-1 both decreased first then increased，and decreased finally，reaching the peak at 24 h after reaction. In conclusion，the expression of MMPs/TIMPs in BMFBs could be induced by heat-inactivated S. agalactiae，which could influence uPA system in regulating the expression and activity of MMPs.

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