Snail1 is positively correlated with atrial fibrosis in patients with atrial fibrillation and rheumatic heart disease

The present study investigated the association between Snail1 and atrial fibrosis in patients with atrial fibrillation (AF) and rheumatic heart disease (RHD) and to determine the possible mechanism underlying this interrelation. A total of 19 patients were included in the current study and were divided into two groups: A sinus rhythm (SR) group (n=9) and an AF group (n=10). All patients underwent heart valve replacement surgery, during which ~200 mg right atrium tissue was obtained. Hematoxylin and eosin and Masson's trichrome-stained sections were used to evaluate the morphological changes of cardiomyocytes and the level of fibrosis. Immunohistochemistry was applied to observe the location and expression of Snail1. Reverse transcription-quantitative polymerase chain reaction was used to measure Snail1 mRNA levels. Western blotting was used to determine changes in the expression of Snail1, as well as in the expression of proteins involved in the Wnt pathway, including Wnt1, Wnt 3a, Wnt8a, Wnt5a and Wnt11. Compared with the SR group, expanded cardiomyocytes and higher collagen deposition was detected in the atrial tissue of the AF group. The expression of Snail1 mRNA and protein was significantly higher in the AF group than in the SR group (P