Effects of chronic Clonorchis sinensis infestation on inflammatory reaction of macrophages

AIM：To evaluate the immune state in rats with chronic Clonorchis sinesis (Cs) infestation by investigating the effects of Cs on macrophage polarization and inflammatory reactions. METHODS：Sprague-Dawley rats were used in the study. Chronic Cs infestation model was reproduced by intragastric perfusion with Cs eggs. Twenty rats were randomly divided into normal group (n=10) and Cs infestation group (n=10). The serum levels of interleukin (IL-4) and IL-10, tumor necrosis factor α(TNF-α) and interferon γ (IFN-γ) were detected by ELISA. The macrophages were harvested by peritoneal lavage. The differentiation proportion of M1 and M2 macrophages were detected by flow cytometry. The macrophages were divided into control group, normal group and chronic Cs infestation group according to the sources of macrophages. The levels of TNF-α and IL-10 in the culture supernatants were detected by ELISA at 0, 2, 12 and 24 h after lipopolysaccharide (LPS, 10 μg/L) stimulation in vitro. RESULTS：Compared with normal group, chronic Cs infestation increased the serum levels of TNF-α, IFN-γ, IL-4 and IL-10. The differentiation proportion of M1 detected by flow cytometry was 92.1% in normal group and that of M2 macrophages was 93.8% in Cs infestation group. The levels TNF-α and IL-10 in culture supernatants were increased at 2~24 h after LPS stimulation both in normal group and Cs infestation group, but the levels of TNF-α were lower in chronic Cs infestation group than that in normal group at 2 h,12 h and 24 h after LPS stimulation. The level of anti-inflammatory cytokine IL-10 was higher in Cs infestation group than that in normal group at 2 h, 12 h and 24 h after LPS stimulation. CONCLUSION：Chronic Cs infestation increases the serum levels of both pro-inflammatory cytokines and anti-inflammatory cytokines, thus inducing the polarization of M2 macrophages. The macrophages derived from chronic Cs-infected rats produce tolerance in the inflammatory process against LPS in vitro.