Protective effects of a kampo medicine, Hochu-ekki-to (TJ-41) on lethal malarial infection with Plasmodium chabaudi AS in A/J mice

Effects of Hochu-ekki-to (TJ-41) on the course of lethal rodent malarial infection with Plasmodium chabaudi AS were examined in male A/J mice. We examined the mortality, parasitemia and serum cytokines such as IL-12, IFN-γ and IL-4 in the infected and TJ-41-treated/infected mice. There was a significant difference in mortality between infected and treated/infected mice. A high mortality was observed in male mice after infection with P. chabaudi AS. In mice treated with TJ-41, control of the primary infection was achieved, and significantly lower mortality was observed. All surviving males in the treated/infected group showed somewhat smaller peak parasitemias than those in infected controls. Mice in the infected and treated/infected groups displayed significantly elevated serum IL-12 levels on day 4 of infection when compared with the levels from the uninfected animals. Mice in the infected and treated/infected groups displayed significantly elevated serum IFN-γ levels when compared with the levels from the uninfected animals. Furthermore, a significantly higher IFN-γ level was seen in the treated/infected group than that in the infected group on day 4 of infection. The present results suggest that an early production of IFN-γ in the TJ-41-treated/infected mice is associated with a decrease of parasitemia, being responsible for the survival of mice.