Serum Tyrosine Level in Acute Murine Toxoplasmosis

Abstract

Background: Toxoplasmosis is a zoonotic disease caused by the obligate intracellular parasite, Toxoplasma gondii. This global infectious disease has been associated with behavioral changes in rodents and can result in humans' neuropsychiatric symptoms. Since the neurotransmitters alteration can cause a behavioral change, in this study, tyrosine level, as a precursor of dopamine, was evaluated in acute murine toxoplasmosis during 2015 and 2016 in Shiraz, Iran.
 Methods: At the first, 105 tachyzoites of T. gondii were subcutaneously inoculated to 50 BALB/c mice as experimental groups and 10 mice inoculated by PBS considered as the control group. After that, daily, one group of mice was bled, and sera were collected. Then, their serum tyrosine level was evaluated by HPLC method.
 Results: After data analysis, the maximum mean serum tyrosine level was seen at 2th day of post parasite inoculation (0.0194 mg/ ml), with a significant difference compared to the control group (0.0117 mg/ ml, P=0.025). Moreover, the least quantity of serum tyrosine (0.076 mg/ml) was seen on the 5th day, after parasite inoculation, however, no significant difference was seen.
 Conclusion: Serum tyrosine level increased in 2 d after inoculation of Toxoplasma, but the level regularly decreased in successive days. Tyrosine level increased by phenylalanine hydroxylase 2 days after inoculation, then tyrosine decreased by tyrosine hydroxylase in the next days. Toxoplasma tyrosine hydroxylase enzymes, at primary days of toxoplasmosis, effect on tyrosine production, and after that, the most effect on tyrosine consumption.

Serum Dopamine Level in Acute Murine Toxoplasmosis

“…Dopamine levels in the rst to fourth days were not different in the case and control groups, but on the Late acute phase ( fth day of infection), dopamine levels increased. Our previous study, which focuses on tyrosine production (one of the dopamine precursors) in acute murine toxoplasmosis, showed the highest and lowest tyrosine levels in the second and fth-day post-infection, respectively (Asgari et al 2020). While in the current study, dopamine production began on day 5 after infection.…”

“…with these explanations, the parasite's role in changing dopamine levels in the acute phase and its possible effects remains unclear. In our previous study, tyrosine as a dopamine precursor was measured in consecutive days post-Toxoplasma-infection in mice models (Asgari et al 2020). In this regard, this work aimed to measure the serum dopamine levels in acute murine Toxoplasmosis.…”