Musculin enhances the immune function of peritoneal macrophages in mice.

INTRODUCTION: Macrophages play a key role in infection, and musculin (MSC) is closely associated with immune cells. The objective of this study was to investigate the effect of MSC on the immune function of mouse peritoneal macrophages. MATERIAL AND METHODS: Peritoneal macrophages from wild-type (WT) and MSC knockout (MSC-/-) mice were obtained and cultured for 12 hours. The cells were subsequently treated with lipopolysaccharide (LPS). After 24 hours, the peritoneal macrophages and their supernatants were collected. The changes in the adhesion index in each group were then recorded by cell counting, and the phagocytic index and phagocytic rate were calculated via bacterial phagocytosis experiments. Additionally, the levels of interleukin (IL)-1 β, IL-6, IL-10 and tumour necrosis factor α (TNF-α) in the cell supernatant were measured via enzyme-linked immunosorbent assay (ELISA). The ratios of cluster of differentiation (CD) 16/32 and CD206 were analysed via flow cytometry. RESULTS: At 24 hours after LPS treatment, the number of peritoneal macrophages in the MSC-/- group was lower than that in the WT group, while the adhesion index in the former group was higher than that in the latter group. Compared with those in the WT group, the phagocytosis index and phagocytosis rate were significantly lower in the MSC-/- group, while the levels of IL-1 β, IL-6, and TNF-α were higher, and the level of IL-10 was lower. In addition, the number of type 2 (M2) macrophages was lower in the same comparison. CONCLUSIONS: Musculin may enhance the immune function of peritoneal macrophages in mice.