Abstract: This study aimed to explore the effect and mechanism of melatonin on inflammatory response of 3T3-L1 adipocyte induced by lipopolysaccharide (LPS).3T3-L1 preadipocytes were cultured and induced to become mature adipose cells.Pretreated with different concentrations of melatonin for 2h,adipocytes were challenged with LPS (2 μg/mL).After treatment with LPS for different time points,supernatant were harvested and enzyme linked immunosorbent assay (ELISA) was used to detect the concentration ofTNF-α and IL-6.qRT-PCRwere carried out to identify mRNA levels of TNF-α and IL-6.Western blot was used to assay p-IκBα.The results showed that 3T3-L1 adipocyte secreted TNF-α and IL-6 significantly after treatment with LPS.Melatoninsignificantly reduced TNF-α and IL-6 expression and secretion of 3T3-L1 adipocyte induced by LPS in a dose-dependent manner.Western blot demonstrated that melatonin inhibited IκBα phosphorylation induced by LPS significantly.With these results,it was concluded that melatonin alleviated inflammatory response of 3T3-L1 adipocyte induced by LPS through inhibition of NF-κBsignal transduction.

Key words: 3T3-L1 adipocyte, melatonin, inflammatory response, NF-&kappa, B