[Effects of interleukin-17 antibody on polarization of macrophages in adipose tissue of high-fat diet fed mice exposed to bisphenol A].

OBJECTIVE

To investigate the effects of interleukin-17(IL-17) antibody on polarization of adipose tissue macrophages(ATM) in mice fed with high-fat diet(HFD) exposed to bisphenol A(BPA).

METHODS

Four week-old male C57 BL/6 mice were divided into control group, IgG group, IL-17 antibody group, 1000 nmol/L BPA group, 1000 nmol/L BPA+IgG group, and 1000 nmol/L BPA+IL-17 antibody group according to random number table method. Eight mice per group were fed with HFD and BPA was exposed by drinking water. The IgG group and the 1000 nmol/L BPA+IgG group were intraperitoneally injected with 100 μg IgG antibody once a week, and the IL-17 group and the 1000 nmol/L BPA+IL-17 antibody group were intraperitoneally injected with 100 μg IL-17 antibody once a week. After 16 weeks, the mice were sacrificed, and serum samples were collected for serum separation. Leptin level was measured by enzyme-linked immunosorbent assay(ELISA). The expression of IL-1β, IL-6 and monocyte chemoattractant protein-1(MCP-1)inflammatory cytokines were observed by immunohistochemistry(IHC) of adipose tissue of epididymis. The activity of inducible nitric oxide synthase(iNOS)and arginase-1(Arg-1)was measured by ELISA, and the proportion of M1 and M2 ATMs was measured by flow cytometry(FCM). The expression of CD11 c and CD206 mRNA was measured by qRT-PCR.

RESULTS

Compared with the control group, serum leptin, the expressions of inflammatory cytokines IL-6, IL-1β and MCP-1 in adipose tissue were increased in 1000 nmol/L BPA group, the proportion of M1 type ATM was increased(22.000%±0.500% vs. 31.467%±0.379%), iNOS activity was increased, CD11 c mRNA expression was increased, Arg-1 activity was decreased, CD206 mRNA expression was decreased, the differences were statistically significant(P<0.05), but the proportion of M2 type ATM was decreased insignificantly(P>0.05). There was no significant change in IgG group. Compared with 1000 nmol/L BPA group, IgG+1000 nmol/L BPA group had no significant change. In 1000 nmol/L BPA+IL-17 antibody group, serum leptin was decreased, the expressions of inflammatory factors IL-6, IL-1β and MCP-1 in adipose tissue were down-regulated, and the proportion of M1 type ATM was decreased(31.467%±0.379% vs. 22.933%±0.153%), iNOS activity was decreased, CD11 c mRNA expression was decreased, and the proportion of M2 type ATM was increased(4.847%±0.655% vs. 7.840%±0.555%), Arg-1 activity was enhanced, and CD206 mRNA expression was up-regulated, the differences were statistically significant(P<0.05).

CONCLUSION

IL-17 antibody may reduce the secretion of ATM inflammatory factors by inhibiting the polarization of ATM to M1 type, thus improving the inflammation of adipose tissue in BPA-infected HFD-fed mice.