Increased Cytokine and Nitric Oxide Levels in Serum of Dogs Experimentally Infected with Rangelia vitalii

This study aimed to measure the levels of interferon-gamma (IFN-${\gamma}$), tumor necrosis factor-alpha (TNF-${\alpha}$), interleukin 1 (IL-1), interleukin 6 (IL-6), and nitrite/nitrate ($NO_x$) in serum of dogs experimentally infected with Rangelia vitalii. Twelve female mongrel dogs were divided into 2 groups; group A (uninfected controls) composed by healthy dogs (n=5) and group B consisting of dogs inoculated with R. vitalii (n=7). Animals were monitored by blood smear examinations, which showed intraerythrocytic forms of the parasite on day 5 post-infection (PI). Blood samples were collected through the jugular vein on days 0, 10, and 20 PI to determine the serum levels of IFN-${\gamma}$, TNF-${\alpha}$, IL-1, IL-6, and $NO_x$. Cytokines were assessed by ELISA quantitative sandwich technique, and $NO_x$ was measured by the modified Griess method. Cytokine levels (IFN-${\gamma}$, TNF-${\alpha}$, IL-1, and IL-6) were increased (P<0.01) in serum of infected animals. Serum levels of $NO_x$ were also increased on days 10 PI (P<0.01) and 20 PI (P<0.05) in infected animals. Therefore, the infection with R. vitalii causes an increase in proinflammatory cytokines and nitric oxide content. These alterations may be associated with host immune protection against the parasite.