抗血管紧张素Ⅱ-1型受体自身抗体抑制大鼠醛固酮分泌的机制研究

Tissue perfusion reduction is an important pathophysiological change in preeclampsia (PE). When perfusion is reduced, angiotensin II (AngII) induced aldosterone secretion is increased to improve tissue perfusion. Research has shown that anti-angiotensin II-1 receptor autoantibodies (AT1-AA) with a similar function to AngII found in PE patients can inhibit the secretion of aldosterone, our previous study also confirmed this point, but the mechanism is not clear. This study will be based on the existing research, using the purified AT1-AA as a research tool, the adrenal glomerulosa cells as the research object, from both in vitro and in vivo levels, changes in the expression and function of adrenal glomerulosa cells AT1 receptor induced by AT1-AA will be observed. Through acute and chronic experiments, the mechanism of molecular changes of expression of aldosterone synthesis key enzymes and signaling molecules induced by AT1-AA will be studied. AT1-AA induced injury on adrenal cortex zona glomerulosa cells and its signal Transduction pathway will also be studied by agarose gel electrophoresis, immunohistochemistry, trace enzyme activity detection technology, Western blot and RNAi technologies. In conclusion, this study will be conducted from two levels of cells and organs, from two aspects of in vitro and in vivo, from acute and chronic angles to elucidate the mechanism of AT1-AA induced aldosterone secretion decline and possible significance, in order to deepen the understanding of relationship between AT1-AA and preeclampsia, and provide new ideas for the clinical treatment of the disease.

组织灌流减少是子痫前期（PE）重要的病理生理改变。灌流减少时，血管紧张素II（AngII）致醛固酮分泌增加以改善组织灌流。但有研究表明，存在于PE体内的作用类似于AngII的血管紧张素II-1型受体自身抗体（AT1-AA）却抑制醛固酮分泌，且机制不清。本课题在已有研究的基础上，以纯化的AT1-AA为研究工具，以肾上腺皮质球状带细胞为研究对象，从离体和在体两个层面，观察AT1-AA致肾上腺皮质球状带细胞AT1受体表达和功能的变化；从急性和慢性实验两个角度，研究AT1-AA致醛固酮合成的信号分子和关键酶表达变化的机制；采用免疫印迹和RNAi技术观察AT1-AA对肾上腺皮质球状带细胞的损伤及其信号转导通路。总之，本研究拟从细胞和器官两个水平，离体和在体两个层面，急性和慢性两个角度阐明AT1-AA抑制醛固酮分泌的机制和可能的意义，加深对AT1-AA与PE发病关系的理解，为临床治疗该病提供新思路。

组织灌流减少是子痫前期（PE）重要的病理生理改变。灌流减少时，血管紧张素II（AngII）致醛固酮分泌增加以改善组织灌流。但有研究表明，存在于PE体内的作用类似于AngII的血管紧张素II-1型受体自身抗体（AT1-AA）却抑制醛固酮分泌，且机制不清。本课题在已有研究的基础上，一方面从临床着手，分析了临床上子痫前期孕妇血清中AT1-AA以及醛固酮水平，结果显示：子痫前期孕妇血清中的AT1-AA呈高检出率，醛固酮呈低水平，并且子痫前期孕妇体内的AT1-AA水平与醛固酮水平呈负相关性。另一方面从基础研究着手，以纯化的AT1-AA为研究工具，从离体和在体两个层面，观察AT1-AA引起醛固酮合成下降的原因。动物在体水平，我们发现AT1-AA被动免疫孕鼠可以造成孕鼠出现子痫前期样症状和醛固酮水平下降明显，肾素-血管紧张素-醛固酮系统紊乱，形态学显示肾上腺出现损伤；进一步离体细胞实验发现，AT1-AA可通过活化细胞表面的AT1R而使细胞内钙离子持续处于高水平，在短时间内会促进醛固酮合成增加，但在长时间作用下由于钙离子的细胞毒性作用反而使醛固酮合成减少。总之，本研究从临床研究和基础研究两方面，急性和慢性两个角度解释了AT1-AA抑制醛固酮分泌的机制，从而为临床治疗PE提供了新的思路。