Comparison of acute strain and attenuated Toxoplasma gondii strain in immune response and induction of testosterone changes in rats

Toxoplasma gondii is a pathogenic protozoan with a worldwide spread. Since this parasite is capable of producing testosterone hormone changes and has an important role in health, in this study we will investigate the immune response and testosterone changes in rats after immunization with Toxoplasma gondii attenuated strain. For this purpose, 21 rats were divided into three groups (each n=7). The first group received the acute strain with low dose and the second group received the attenuated strain and the third group was considered as the control. One month after the immunization, mice were challenged. Blood samples were collected to investigate changes in testosterone and antibodies. One month after challenge, brain and liver tissue samples were taken for pathological examination. The results showed that the antibody response was significantly different in the group injected with the attenuated strain compared to the control group. The attenuated strain was also able to prevent changes in testosterone after challenge, which was significantly different (P≤0.05) from the control group. In pathological findings the least pathogenic changes were observed in the tissues of the group injected with the attenuated strain. Symptoms in this tissue included mild bleeding and low infiltration of multifocal inflammatory mononuclear cells. The results showed that the attenuated strain protected the mice against the pathogenicity and alterations of testosterone induced by challenge with Toxoplasma gondii. The results of this study confirm that the attenuated strain can be considered for further vaccine researches.