[Expression of IL-2 and TNF-alpha in the liver and the effect of injection of these cytokines on liver fibrosis in mice infected with Schistosoma japonicum].

ABSTRACT

OBJECTIVE: To detect the expression of IL-2 and TNF-alpha in the liver at different period postinfection of Schistosoma japonicum and their effect on liver fibrosis after supplementary injection of these cytokines. METHODS: Mice were infected with schistosome cercariae and divided into 3 groups. Two groups were injected (i.p.) every other day with IL-2 and TNF-alpha respectively for consecutive 4 wk. The third group and an uninfected group of normal mice were regarded as control. The ABC immunohistochemistry and pathologic image multimedia quantification system were applied to detect activity of IL-2 and TNF-alpha. RESULTS: The level of IL-2 and TNF-alpha in the liver in infected but untreated group slowly decreased (from 8, 11, 14 to 18 wk). The supplementary injection of the cytokines at 6 wk postinfection in the two groups increased the cytokines significantly, the level of IL-2 or TNF-alpha was higher at 1-8 wk after the last injection than that of both infected and uninfected control groups (P < 0.01). The granulomatous inflammation and fibrosis in the livers of the two groups were slighter than that of the control. CONCLUSION: At the 6th wk postinfection with egg deposition, exogenous supplementation with TNF-alpha or IL-2 induces enhanced expression of the two kinds of cytokines, corresponding to a diminished degree of the liver granulomatous inflammation and fibrosis.