Monocyte-derived macrophages: The supplements of hepatic macrophage in Echinococcus multilocularis infected mice

Alveolar echinococcosis is a potentially lethal zoonosis caused by the cestode Echinococcus multilocularis. This study is to investigate the dynamic changes of monocytes, macrophages, and related cytokines in animal models of persistent infection of E. multilocularis.

An infection model was established by intraperitoneal injection of a protoscolex suspension. The pathological changes of liver were observed by HE staining. The percentage of Ly6C^hi and Ly6C^lo Monocytes in peripheral blood was detected by flow cytometry. The distribution and expression of CX3CL1, CX3CR1, iNOS, CD163, and CD11b in the liver were detected by immunohistochemistry. The mRNA expression of tumor necrosis factor-α (TNF-α) and Arg1 in the liver was detected by quantitative reverse transcription polymerase chain reaction. The expression of INF-γ, interleukin-17 (IL-17), IL-4, and IL-10 in peripheral blood was detected by enzyme-linked immunosorbent assay.

Hematoxylin-eosin(HE) staining showed that significant lesions appeared in the later stages of infection in the liver. The proportion of Ly6C^hi monocytes in the peripheral blood of the experimental group mice decreased after a brief rise, Ly6C^lo monocytes decreased first and then increased. The expression of CX3CL1, CX3CR1, CD11b, CD163, and iNOS in the mice liver of the experimental group was increased. The expression level of TNF-α and Arg1 mRNA in the liver of the experimental group mice increased. The expression level of IFN-γ, IL-17, IL-4, and IL-10 increased with the duration of infection.

Monocytes as a supplement to hepatic macrophage, monocytes and kupffer cells may both participate in Th1 and Th2 immune responses by differentiating into M1 or M2 at different stages of E. multilocularis infection.