Abstract
To investigate the impact of Sitagliptin against obesity and the underlying mechanism. Obese immature mice were treated with 10, 30, and 90 mg/kg Sitagliptin, respectively. The body weights were recorded and the level of serum biochemical indexes were detected. The visceral fat ratio of each mouse was determined. The pathological change in adipose tissues was determined by HE staining, while F4/80 and CD206 levels in adipose tissues were determined by the immunohistochemical analysis. Lipid formation was evaluated by Oil red O staining assay. RAW264.7 cells were stimulated using oxLDL, followed by being incubated with different concentrations of Sitagliptin. The release of ADPN, IL-6, IL-1β, TNF-α, and the activity of SOD, was measured by ELISA assay. Western blotting was applied to determine adipsin, Nrf2, Keap1, and HO-1 protein levels. ROS level was checked using the DCFH-DA assay. RT-PCR assay was utilized to detect the mRNA levels of IL-6, IL-1β, TNF-α, Nrf2, Keap1, and HO-1. The body weight gain, infiltration of multinucleated cells, enlarged size of adipocytes, increased lipid accumulation, elevated visceral fat ratio, declined ADPN level, upregulated adipsin, and disordered serum biochemical indexes in obese immature mice were statistically significantly reversed by Sitagliptin. Excessive release of inflammatory factors and upregulated F4/80 and CD206 were observed in obese immature mice, which were statistically significantly repressed by Sitagliptin. Furthermore, the elevated MDA level, increased SOD activity, and inhibited Nrf2 pathway in obese immature mice were significantly reversed by Sitagliptin. In oxLDL stimulated RAW264.7 cells, increased release of inflammatory factors, ROS, and MDA, elevated SOD activity, and inactivated Nrf2 pathway were observed, which were statistically significantly abolished by the treatment of Sitagliptin. Sitagliptin alleviated obesity in immature mice by inhibiting inflammation and oxidative stress.