血管紧张素转化酶2对Ang Ⅱ诱导的牛乳腺上皮细胞炎症损伤的缓解作用

Angiotensin-converting Enzyme 2 on Ang Ⅱ-induced Mitigation of Inflammatory Injury in Bovine Mammary Epithelial Cells

以不同浓度血管紧张素Ⅱ(AngⅡ)诱导牛乳腺上皮细胞(MAC-T)炎症损伤,探讨血管紧张素转化酶2(ACE 2)的变化及与AngⅡ的相互作用。研究包括:ELISA检测细胞上清中细胞炎性因子的分泌或释放;Western blot检测细胞ACE 2和ACE的蛋白表达变化,并进行相关性分析;添加ACE 2活性蛋白对AngⅡ诱导损伤的保护作用。结果显示:1)AngⅡ处理MAC-T,细胞上清中促炎因子TNF-α、IL-6、IL-8含量显著(P<0.05)或极显著(P<0.01)增加,抗炎因子IL-10含量显著降低(P<0.05);2)不同浓度AngⅡ处理细胞后,ACE 2蛋白表达均有降低,10-6 mol·L^-1 AngⅡ处理后显著降低(P<0.05);ACE蛋白表达结果相反;ACE 2与AngⅡ浓度之间存在显著负相关;3)添加外源性ACE 2活性蛋白,细胞上清中TNF-α、IL-6和IL-8浓度均有一定程度的下降,IL-10浓度升高。本研究表明ACE 2/ACE轴的失衡是AngⅡ诱导细胞炎性损伤的主要原因。高水平AngⅡ可激活炎症因子促进炎症反应,是促进炎症反应的主要介质,ACE 2可以通过降解AngⅡ,抑制其对炎症反应的上调效应。

Inflammatory damage of bovine mammary epithelial cells(MAC-T) was induced by different concentrations of angiotensin Ⅱ(Ang Ⅱ), and the changes of angiotensin-converting enzyme 2(ACE 2) and the interaction with Ang Ⅱ were explored. The research includes: Detecting the secretion or release of inflammatory factors in cell supernatant by ELISA;Western blot analysis of protein expression changes of ACE 2 and ACE, and correlation analysis;The protective effect of ACE 2 active protein on Ang Ⅱ induced injury. Results were as follows: 1) The levels of pro-inflammatory factors TNF-α, IL-6 and IL-8 in the supernatant of bovine MAC-T cells in the Ang Ⅱ treatment were significantly(P<0.05) or very significantly increased(P<0.01), the anti-inflammatory factor IL-10 content was significantly reduced(P<0.05);2) Treatment with different concentrations of Ang Ⅱ, the expression of ACE 2 protein was decreased, and the 10-6 mol·L^-1 Ang Ⅱ treatment group was significantly decreased(P<0.05);the expression of ACE protein was reversed. There was a significant negative correlation between ACE 2 and Ang Ⅱ concentrations;3) After adding exogenous ACE 2 active protein, the results showed that the concentration of TNF-α, IL-6 and IL-8 in the supernatant of the cells decreased to some extent, and the concentration of IL-10 increased. The imbalance of the ACE 2/ACE axis is the main cause of inflammatory injury induced by Ang Ⅱ. The conclusion showed that high level of Ang Ⅱ can activate inflammatory factors to promote inflammatory response and is the main mediator of inflammatory response. ACE 2 can inhibit the up-regulation of inflammatory response by degrading Ang Ⅱ.