Principles: This study aims at investigating how zinc deficiency and pinealectomy affect nitric oxide levels in rats infected by Toxoplasma gondii.
Methods: The study was conducted on a total of 50 adult, male rats of Spraque-Dawley species. The study groups were as follows: General, intact control group (Group I, n = 10), infected control group (Group II, n = 10), infected and zinc-deficient group (Group III, n = 10), infected and pinealectomized group (Group IV, n = 10), infected, zinc-deficient and pinealectomized group (Group V, n = 10). After the experiment the rats were decapitated and levels of zinc, melatonin and total nitrite were identified in the blood samples collected.
Results: The total nitrite levels in groups IV and V were more than those in all other groups (p <0.01). The total nitrite levels in Group II were also higher than those in Groups I and III (p <0.01). Plasma zinc levels in the zinc-deficient group and zinc-deficient and pinealectomized group were lower than those in all other groups, while melatonin levels were lower in infected pinealectomized group (Group IV) and infected, zinc-deficient and pinealectomized group (Group V) than all others (p <0.01).
Conclusions: The present study shows that plasma nitric oxide levels increase during Toxoplasma gondii infection, but this increase becomes more apparent in the presence of melatonin deficiency and is inhibited by zinc deficiency.