Study On The Effect Of Angiotensin â…¡ On Atrial Structural Remodeling In Abdominal Aorta Banding Rats

Objective: To explore the effects of angiotensin II (Ang II) on atrial fibrosis and gap junction connexin (Cx40,Cx43) remodeling in suprarenal abdominal aorta banded rats.Methods: Forty male Wistar rats were randomly assigned to four groups: control group (C),abdominal aorta banded group (AB),abdominal aorta banded rats treated with benazepril (20mg·kg^-1·d^-) group (B),abdominal aorta banded rats treated with valsartan (40mg·kg^-1·d^-1) group(V). After eight weeks' feed, Ang II in plasma and cardiac tissue were determined by RIA. The degree of atrial fibrosis was measured with Masson staining and the distribution of Cx40,Cx43 were characterized by immunohistochemistry in rats. The semi-quantitative assessment was performed to analyze the content of fibrous tissue and density of Cx40,Cx43 in atrium.Results: Eight weeks after operation, survivors were 9 in group C, 9 in group AB, 8 in group B and 9 in group V. (1) Compared with group C, the plasma and myocardium concentration of Ang II in group AB and group V increased markedly (P<0.01) , but those in group B had no obvious changes. (2) The content of atrial fibrous tissue in group AB increased significantly compared with group C, while density of Cx40,Cx43 decreased and they were mainly located at the side to side interconnections instead of being confined to the intercalated discs as observed in group C; The content of fibrous tissue in group B and group V were diminished significantly (P<0.01) while Cx40,Cx43 levels increased compared with group AB, and the inhomogeneity in distribution decreased.Conclusion: It may be one of the import mechanism of atrial fibrosis and Cx40,Cx43 remodeling that Ang II level elevated for longtime. Benazepril and valsartan can decreased the degree of atrial fibrosis and remodeling of Gap junction connexin effectively.