Abstract:   Objective   To observe the dynamic expression and function of IL-10 and TGF-β1 in liver of BALB/c mice infected with Echinococcus multilocularis (Em).  Methods   Sixty female BALB/c mice were randomly divided into experiment group and control group. Mice in the experiment group were each injected with 0.2 ml Em protoscolex suspension (containing about 400 protoscoleces), while those in control group received same volume of normal saline. At 2, 8, 30, 90, 180, and 360 d after infection, 5 mice from each group were sacrificed and liver specimens were collected for pathological examination and immunohistochemical detection for IL-10 and TGF-β1.  Results   In mice of the experiment group, Em cysts in different sizes were found in the abdominal cavity and the liver tissue, which gradually enlarged with the time. HE staining showed infiltration of lymphocytes in liver tissue, pathological change between the cyst wall and hepatic cells. In the control, the liver lobules showed integrity and inflammatory cells were seen occasionally. The level of IL-10 expression in liver tissue of the infected mice increased with the time, and reached a peak  [(16.39±1.73)%]  at 90 d post-infection and maintained a high level thereafter. The expression of TGF-β1 also reached the highest level [(23.69±2.29)%]. Both were significantly higher than the control (P<0.01), though a low level expression was found in the control at 90 d post-injection.   Conclusion   The expressions of IL-10 and TGF-β1 both increase in the middle and late stages of the infection. Besides, their inhibited functions do not be helpful for clearing and controlling Echinococcus multilocularis infection in livers.

Key words: Echinococcus multilocularis, CD4⁺CD25⁺ regulatory T cells, Cytokine