Effect of zinc supplementation on E-ADA activity, seric zinc, and cytokines levels of Trypanosoma evansi infected wistar rats

• Trypanosoma evansi is a flagellated protozoan that causes disease in many domestic and wild animals.
• Rats infected with trypanosomes and treated with zinc showed the improvement of the immune status and has prolonged life.
• Zinc supplementation was able to increase the seric levels of zinc, a mineral that has been proved to be reduced in serum.
• The treatment with zinc presented immunomodulatory effect, as this relates various physiological functions.
• Administration of zinc showed different actions on E-ADA activity, reducing its on lymphocytes and increasing on serum.

The aim of this study was to evaluate the effect of zinc supplementation on the ecto-adenosine deaminase activity (E-ADA), zinc seric levels and cytokines (TNF-α, IL-1, IL-6, and IL -10) on rats experimentally infected by Trypanosoma evansi. Four groups with 10 rats each were used as negative controls (groups A and B), while the animals from the groups C and D were infected intraperitoneally with 0.1 mL of cryopreserved blood containing 1.4 × 104 of trypanosomes. Animals of groups B and D received two doses of Zinc (Zn) at 5 mg kg−1, subcutaneously, on the 2nd and 7th day post-infection (PI). Blood samples were collected on days 5 (n = 5) and 15 PI (n = 5). Zn supplementation was able to increase the rat's longevity and to reduce their parasitemia. It was observed that seric Zn levels were increased on infected animals under Zn supplementation. Animals that were infected and supplemented with Zn showed changes in E-ADA activity and in cytokine levels (P < 0.05). Zn supplementation of healthy animals (Group B), increased the E-ADA activity, as well as reduced the concentration of cytokines. Infected animals from groups C and D showed increased levels of cytokines. Finally, we observed that Zn supplementation led to a modulation on cytokine's level in rats infected by T. evansi, as well as in E-ADA activity.