〔Abstract〕 Objective To explore the regulatory effects of ResolvinD1(RVD1) on autophagy and apoptosis of cardiomyocytes in aging rats, and the effects of RVD1 on mitochondria-associated endoplasmic reticulum membranes(MAMs) of myocardial tissue. Methods Thirty 18-month-old SD rats were randomly divided into model group, low-dose RVD1 group and high-dose RVD1 group, with 10 rats in each group, and another 10 6-month-old SD rats were selected as control group. The low-dose RVD1 group and high-dose RVD1 group were injected with 50 ng/ml and 100 ng/ml RVD1 through the tail vein, respectively, control group and model group were injected with the same amount of phosphate buffered saline(PBS) for 21 days. The β-galactosidase activity of rat myocardial tissue was determined by p-nitrophenol method, the histopathological changes of rat myocardial tissue were detected by hematoxylin-eosin(HE) staining, and the collagen deposition in rat myocardial tissue was observed by Masson staining, apoptosis of rat myocardial cells was detected by dUTP in situ end labeling mediated by terminal deoxynucleotide transferase(TUNEL), the expression of autophagy marker microtubule-associated protein 3(LC3) was detected by immunohistochemical S-P method, the ratio of LC3-Ⅱ/LC3-Ⅰ and the expression of Beclin-1, p62 in rat myocardial tissue were determined by Western blot, the structure of MAMs in rat myocardial tissue was observed by transmission electron microscopy, the expression levels of glucose-regulatory protein 75(GRP75), volt-dependent anion channel 1(VDAC1) and mitochondrial fusion protein 2(Mfn2) in rat myocardial tissue were determined by Western blot. Results Compared with model group, β-galactosidase activity of myocardial tissue decreased in low-dose RVD1 group and high-dose RVD1 group(P<0.05), myocardial fiber breakage and myocardial cell damage were significantly alleviated, collagen fiber deposition was significantly reduced, and the proportion of TUNEL positive cells in myocardial tissue decreased(P<0.05), the positive rate of LC3 protein increased(P<0.05), the ratio of LC3-Ⅱ/LC3-Ⅰ increased, the relative expression level of Beclin-1 protein was up-regulated and the relative expression level of p62 protein was down-regulated(P<0.05), the structure of MAMs was tighter, and the percentage of MAMs in mitochondrial circumference also increased(P<0.05), the relative protein expressions of GRP75, VDAC1 and Mfn2 were up-regulated(P<0.05). Compared with low-dose RVD1 group, β-galactosidase activity in high-dose RVD1 group further decreased(P<0.05), no obvious damage was observed in myocardial tissue, collagen fiber deposition was further decreased, the proportion of TUNEL positive cells in myocardial tissue decreased(P<0.05), and the positive rate of LC3 protein increased(P<0.05), LC3-Ⅱ/LC3-Ⅰ ratio increased, Beclin-1 relative expression level was up-regulated and p62 relative expression level was down-regulated(P<0.05),the structure of MAMs was more compact, and their percentage in mitochondrial circumference further increased(P<0.05), the relative expressions of GRP75, VDAC1 and Mfn2 were further up-regulated(P<0.05). Conclusion RVD1 can activate autophagy, alleviate myocardial apoptosis and collagen fiber deposition, and promote mitochondria-associated endoplasmic reticulum membranes in aging rats.