Abstract:

Objective To measure the retention of trace elements in different tissues of the body in mice infected by weakly virulent strain TgCtwh6, the dominant genotype of Chinese 1 (ToxoDB #9), and investigate the effects of the infection on metabolism of trace metal elements in the mouse tissues. Methods Mouse models of TgCtwh6 at acute and chronic infection were established respectively, and control group was established (n=6 for each group). The levels of various metal elements (Fe²⁺, Cu²⁺, Mn²⁺, Zn²⁺, Mg²⁺ ) in different tissues (heart, liver, spleen and kidney) of the infected mice were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Western blot was performed to measure the protein expression of the metal element transporter ZIP 8 (Zrt- and Irt- like protein 8), and superoxide dismutase (SOD) activity kits were used to detect the activity of SOD in liver tissues. Finally, the results obtained in each group were statistically analyzed. Results Compared to the control group, the levels of Fe²⁺, Mn²⁺ and Zn²⁺ in the liver of the mice at acute and chronic infection were increased [(76.348±11.613) μg/g and (88.545±10.555) μg/g vs. (52.388±6.165) μg/g, (1.298±0.065) μg/g and (1.405±0.066) μg/g vs. (1.141±0.110) μg/g, (17.506±0.824) μg/g and (17.031±0.907) μg/g vs. (15.650±0.305) μg/g, respectively], yet the content of Fe²⁺ in spleen, Cu²⁺ and Zn²⁺ in heart was downregulated [(128.519±13.531) μg/g and (120.309±10.023) μg/g vs. (147.720±15.303) μg/g, (5.189±0.255) μg/g and (5.631±0.485) μg/g vs. (6.440±0.740) μg/g, (17.034±0. 974) μg/g and (16.858±0.953) μg/g vs. (19.258±0.965) μg/g, respectively]. The levels of Mn²⁺ and Mg²⁺ in the heart of mice at acute infection were lower than those of control group [(0.605±0.052) μg/g vs. (0.686±0.051) μg/g, (153.346±3.221) μg/g vs. (163.012±8.204) μg/g, respectively]. Protein ZIP 8 was up-regulated in the liver of mice at acute and chronic infection as compared with that of control group, and the protein level was higher at chronic infection than at acute infection (F=35.240, P<0.05). SOD activity was (14.041±0.734) U/mL, (16.463±0.616) U/mL and (15.859±0.780) U/mL, respectively, in the liver of mice in the control group, mice at acute and chronic infection. The differene was significant (F=9.370, P<0.05). Conclusion Infection of the mice with TgCtwh6, either at acute or chronic infection, can lead to up-regulation or down-regulation of partial trace metal elements in the tissues of mice as well as upregulated ZIP 8 expression, which may activate SOD activity and function roles in protecting the liver.

Key words: Toxoplasma gondii, Mice, Chinese 1 genotype strain, Trace metal elements, Liver