SMN1 and Myocardial fibrosis: Masson and PSR staining indicated that the degree of myocardial perivascular and intercellular fibrosis was significantly aggravated in Dox group (Fig. 2C, D), and IHC staining indicated that the expression of myocardial fibrosis markers (a-SMA and collagen III) was significantly increased in Dox group (Fig. S3C).