Protective effects of chronic clonorchis sinensis infestation on lungs of septic rat via M2 macrophages polarization

Abstract

Objective To preliminarily investigate the protective effect of chronic clonorchis sinesis(Cs) infestation against sepsis in Sprague Dawley(SD) rats in order to explore its underlying mechanism. Methods Chronic Cs infestation model of SD rats was reproduced by intra-gastric administration with Cs ova.Twenty rats were randomly(random number) divided into normal group(n=10) and Cs group(n=10). The proportion of differentiation in M1 and M2 macrophages were detected by flow cytometry. The expressions of Arg-1(arginine-1), FIZZ 1, iNOs and TNF-αmRNA were examined by reverse transcriptase polymerase chain reaction(RT-PCR). The cecal ligation and puncture(CLP) procedure was performed to reproduce sepsis model of SD rats. Sixty rats were randomly(random number) divided into control group, SHAM group, CLP group, Mφ+ CLP group, Cs-Mφ+ CLP group, and Cs-CLP group. The cumulative mortalities were calculated. The pathological changes of the lung tissue in different groups were demonstrated by HE staining. The serum levels of cytokines TNF-α and IL-10 were detected by ELISA at 0, 24, 48 and 72 h after CLP procedure. Results Compared with M1 peritoneal macrophages differentiation in control group(91.9%), rat peritoneal macrophages were activated to M2 differentiation(95.1%) in chronic Cs infection group. RT-PCR assay showed expression of Arg-1 and FIZZ 1 mRNA were higher in M2 macrophages, and on the contrary, the expression of iNOS mRNA expression was higher in M1 macrophages. The expression of TNF-α mRNA in M1 was significantly higher than that in M2, whereas the expression of IL-10 mRNA in M2 was higher than that in M1.The cumulative mortality of septic rats 72 h after CLP procedure were much lower in both chronic Cs infestation group and M2 macrophages adoptive transfer group(CLP group 70%vs.Mφ+ CLP group 50%vs.Cs-Mφ+ CLP group 30%vs.Cs-CLP group 0%, P<0.05). In these two groups, the pathological damages in lung tissues were significantly improved. The serum level of TNF-α was decreased and the anti-inflammatory IL-10 level was increased significantly in these two groups with Cs compared with other groups. Conclusion M2 macrophages polarization induced by chronic Cs infestation with M2 phenotype gene and expression of anti-inflammatory cytokine gene play key role in increasing anti-inflammatory cytokines and decreasing pro-inflammatory cytokines to allerviate organ damage and ameliorating the survival rate in septic rats. Key words: Sepsis; Chronic clonorchis sinensis infection; Alternatively activated macrophages(M2); Cytokines; Gene expression