Abstract: Objective To explore the influence of syndecan-1 (Sdc1) on biological behaviors of myocardial fibroblasts,and to provide an experimental basis for the prevention of ventricular remodeling after myocardial infarction.Methods Myocardial fibroblasts of Sprague-Dawley (SD) rats were cultivated in vitro.Sdc1 siRNA plasmid and Sdc1 high expression plasmid were transferred into myocardial fibroblasts,respectively.Blank control,unconcerned sequence and empty vector plasmid were used as negative control.Flow cytometry was used to detect cell proliferation.Cholecystokinin octapeptide (CCK-8) was used to detect cell viability.Enzyme-linked immunosorbent assay (ELISA) was used to detect collagen (hydroxyproline) secretion.Transwell method was used to evaluate vertical migration of the cells.Results The proportion of S phase cells (8.36%±0.23%),proliferation index (13.2%±0.5%),cell viability (1.72±0.12),collagen (hydroxyproline) secretion (1162.3±60.4 pg/ml),and the number of migration cells (170 cells/hole) for the myocardial fibroblasts transferred with Sdc1 siRNA plasmid were all higher than those in the myocardial fibroblasts of blank control and negative control group (all P<0.01).The proportion of S phase cells (6.48%±0.22%),proliferation index (10.8%±0.6%),cell viability (1.30±0.11),collagen (hydroxyproline) secretion (346.8±52.1 pg/ml),and the number of migration cells (50 cells/hole) for the myocardial fibroblasts transferred with high Sdc1 expression plasmid were all lower than those of the myocardial fibroblasts of blank control and empty vector plasmid group (P<0.01 for all).Conclusion Sdc1 can inhibit proliferation,activity,collagen secretion and migration capacity of myocardial fibroblasts.