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目的研究血管紧张素Ⅱ(angioensinⅡ,AngⅡ)的2种主要受体亚型AT1和AT2在胰腺星状细胞(pancreatic stellate cells,PSCs)上的表达情况,并在此基础上探讨其表达的调控机制。方法分离培养大鼠PSCs,采用Northern blot和Western blot方法检测正常和活化细胞的AT1和AT2受体mRNA和蛋白表达情况,正常和纤维化胰腺组织及肾脏组织为阳性表达对照。结果新鲜分离的PSCs 不表达AT1和AT2,培养活化的PSCs仅表达AT1而不表达AT2,表明AT1为活化PSCs上的惟一Ang Ⅱ受体。进一步研究发现,在培养的PSCs,AngⅡ可下调AT1表达,提示AngⅡ对PSCs作用为一负反馈方式。结论活化的PSCs表达有AT1受体。而不表达AT2受体,提示PSCs是Ang Ⅱ作用的重要靶细胞并通过AT1受体介导。Ang Ⅱ可下调AT1表达,这种负反馈调节方式可能是细胞自身防御的一种反应。
Objective To investigate the expression of AT1 and AT2, two major receptor subtypes of angiotensin Ⅱ (AngⅡ) in pancreatic stellate cells (PSCs), and to explore the mechanism of their regulation . Methods Rat PSCs were isolated and cultured. The expression of AT1 and AT2 receptor mRNA and protein in normal and activated cells were detected by Northern blot and Western blot. The normal and fibrotic pancreatic tissues and kidney tissues were positive control. Results Freshly isolated PSCs did not express AT1 and AT2. The cultured activated PSCs only expressed AT1 but not AT2, indicating that AT1 is the only Ang Ⅱ receptor on activated PSCs. Further study found that, in cultured PSCs, Ang Ⅱ can down-regulate the expression of AT1, suggesting that the effect of AngⅡ on PSCs is a negative feedback mode. Conclusion Activated PSCs express AT1 receptor. But not AT2 receptor, suggesting that PSCs are important target cells of Ang II and mediated by AT1 receptor. Ang Ⅱ can down-regulate AT1 expression. This negative feedback regulation may be a response of cell defense.