Endothelin A Receptor MRNA Expression In Microcirculation Of Gastric Mucosa During The Development Of Liver Cirrhosis In Rats

Objective: To observe endothelin A receptor mRNA expression in gastric mucosal microcirculation and discuss the regulation mechanism of endothelin and its receptor during the development of liver cirrhosis and portal hypertension (PHT) in Wistar rats. Methods: In situ hybridization of mRNA was used to detect the location and the quantity of endothelin A receptor in gastric mucosal microcirculation. 71 male Wistar rats were divided into four groups randomly: control group was 13, 1 month group (degeneration and necrosis period) 20, 2 month group (nodule regeneration period) 20, and 3 month group (false lobule period) 18. Liver cirrhosis and PHT was induced by subcutaneous injection of 60% tetrachloride (CC14). The experiment have 4 main parts. The first, portal pressure and endothelin level in portal and peripheral blood was determined, and the relationship between them was discussed during the period of the formation of liver cirrhosis and PHT. The second, histological changes of liver and gastric corpus were estimated, endothelin receptor mRNA of gastric mucosal microcirculation was examed by in situ hybridization after keeping in liquid nitrogen. The third, mRNA sequences of endothelin receptor A, B, C (ETA, ETB, ETC) of rats were analyzed and a 33 bp ETA probe was designed by "DNAstar" software, finally, ETA mRNA was analyzed by quantitative image analyzer. Result: Along with the formation of liver cirrhosis and PHT, gastric mucosa became thicker and more congestive, portal pressure was elevated gradually, peripheral and portal blood endothelin level was decreased, ETA mRNA was expressed mainly in the postcapillary venule and precapillary arteriole and enhanced remarkably with the reduction of endothelin level and elevation of portal pressure and that was- 3 -dramatically increased in the arteriolar wall. Conclusion: (1)Endothelin level of portal and peripheral blood was decreased gradually with the formation of liver cirrhosis and portal hypertension in rats; (2)ETA mRNA expression was increased in gastric mucosal microcirculation and up-regulated with the descending of endothelin level; (3) These changes should be related to dysfunction of gastric mucosal microcirculation of liver cirrhotic and portal hypertensive rats.