Abstract: 　Objective To observe the effect of signaling inhibitors of tyrosine-protein kinase (TPK), protein kinase C (PKC) and phosphatidylinositol-3-kinase (PI3-K) (tyrphostin-25, D-sphingosine and wortmannin, respectively) on the egg granuloma formation of Schistosama japonicum , and probe the mechanism of the effect. Methods Three signaling inhibitors were injected by tail vein of mice from the thirty-fifth day after infection for five successive days. The liver egg granuloma measurement was performed by histological examination and the kits of ELISA and NO assay were used for the quantitative determination of IFN-γ, IL-4 and NO respectively in murine serum at 6 and 8 weeks after infection. Results The egg granuloma formation of liver tissue was significantly reduced by the specific inhibitors of TPK and PKC in vivo. The ratio of egg granuloma inhibition was up to 56.2% - 63.4% by the effects of PKC inhibitor D-sphingosine. The PKC inhibitor mainly inhibited the expression of IL-4 and the detection of NO level further demonstrated the inhibition. Conclusion The egg granuloma formation could be significantly inhibited by PKC inhibitor in the early stage of Schistosama japonicum infection in mice. These findings suggest that PKC inhibitor might inhibit the Th2 bias and mediate a deviation from Th2 to Th1.

Key words: Schistosoma japonicum, egg granuloma, singnal transduction, Th1/Th2 cytokine