Abstract: Objective To study the anti-inflammatory effect of metformin (Met) on lipopolysaccharide (LPS)-induced inflammation in mice. Methods The mice were divided into control group, LPS group, metformin high dose group (400 mg/kg), metformin medium dose group (200 mg/kg) and metformin low dose group (100 mg/kg). The control group and LPS group were intraperitoneally injected with normal saline, the other groups were injected with different doses of metformin. After 0.5 hours, the control group was injected with normal saline, the other four groups were injected intraperitoneally with LPS. After 6 hours, the spleen index of the mice was measured. The expression of IL-6,TNF-α and IL-10 in mouse serum was detected by ELISA and the expression of IL-6,TNF-α and IL-10 mRNA in mouse liver was detected by RT-PCR. The inflammatory changes of liver tissues in each group were observed by HE staining techniques. Results Compared with the LPS group, the spleen index, IL-6 and TNF-α expression in serum and IL-6 and TNF-α mRNA expression in liver were lower in metformin group, however, IL-10 expression in serum and IL-10 mRNA expression in liver were higher in metformin group. The application of metformin(400 mg/kg) reduced the inflammatory changes of liver tissues in mouse with LPS induced inflammation. Conclusions Metformin has certain anti-inflammatory activity against inflammation induced by LPS in mice.

Key words: Metformin, inflammation, LPS, inflammatory factor