RESUMO
Leishmaniases consist of a group of diseases caused by protozoan parasites of Leishmania genus. The outcome of the disease depends on the immune responses of the host as well as the pathogenicity of the strain of the parasite. In murine models, the inoculation of Leishmania major into resistant mice results in Th1 responses and recovery from the infection. However in the susceptible mice, the same inoculation leads to a profile of Th2 responses. Zinc (Zn) is an essential trace element which is required for the growth and development of the immune responses. In this study, the influence of Zn sulfate on mRNA expression of main cytokines of the immune response was studied in susceptible BALB/c mice infected with L. major. The inoculated mice were divided into 3 groups, namely the untreated (control), the zinc sulfate treated (weeks 2, 4 and 8), and the Glucantime-treated (weeks 4 and 8) mice. During different time points post-infection, the lesion sizes and the parasite burden were measured in all the groups. Moreover, the expression of Ifng, Il4, Il10 and Il12 mRNA levels in the draining lymph nodes of the treated mice were compared to the control mice using real-time PCR. Our data demonstrated significant decreases in lesion sizes and parasite loads in Zn sulfate treated group compared to the untreated group. Moreover, significant fold increases in expression of Ifng transcript were observed in mice treated with Zn sulfate compared to the control. The ratio of Ifng/Il4 mRNA was also higher in Zn sulfate-treated mice compared to Glucantime-treated animals. These results indicate that Zn Sulfate has the ability to induce strong Th1 responses in susceptible BALB/c mice inoculated with L. major.