Investigation of CYP1A1/ CYP11A1 genes expression in testisand adrenal gland of tetrachlorodibenzo-p- dioxin treatedBALB/C adult mice male

Abstract

Dioxins are among the persistent and widespread organic pollutants in the environment that negatively affect the spermatogenesis process in many organisms, through their ability to disrupt the synthesis of sex hormones necessary to complete this process in its natural form. Therefore, this research aimed to study the toxic effect of TCDD on the synthesis of testosterone in male BALB/C mice. To this end, eighteen adult male BALB/C mice were divided into 3 groups (6 mice in each group), the control (first) group was orally dosed with corn oil alone, the second group was dosed with 25 μg/kg of TCDD solved in corn oil, the third group was orally dosed with 50 μg/kg of TCDD. After a week, the mice were sacrificed and their adrenal and testes were isolated. The total mRNA of adrenal and testes tissues were isolated and their respective cDNA were synthetized. Gene expression changes of the most important enzymes involved in the dioxin-detoxification pathway, thecyp1a1, and the key enzyme in the T hormone synthesis chain, the cyp11a1, were studied using RT-qPCR. Our results showed the ability of dioxin to induce changes in the expression of cyp11a1 enzyme, where an increase of 3.4 and 8.6 times was observed in the testes and adrenals of mice dosed with 25 μg/kg of TCDD, respectively, while the dose of 50 μg/kg had inhibitory effect on the expression of this enzyme in the testes and adrenals, where the decrease was 1.7 and 2 times for the testes and adrenals, respectively, compared to the testes and adrenals of the control mice.

Regarding the dioxin detoxification, an increase in the expression of cyp1a1 enzyme in the testes and adrenal gland with percentages (8.3, 4.7) for the dose 25 μg/kg and (1.9, 1.5) for the dose 50 μg/kg, respectively, compared to the control group, where the dose 25 was more effective in Enzyme stimulation than dose 50. Thus, these data indicate that dioxin affects the expression of cyp1a1 and cyp11a1in a dose-dependent manner.