MOLECULAR BIOCHEMICAL AND TOXICOLOGICAL ANALYSIS OF TCDD EFFECTS ON mRNA EXPRESSION OF StAR, CYP450, CYP450Scc, CYP19 AND GAPDH IN MALE ALBINO RATS

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related substances are ubiquitous environmental pollutants that exert adverse effects on reproductive processes. We studied the effects of TCDD on LH and testosterone hormone levels and gene expression levels of StAR, CYP450, CYP450Scc, CYP19 and GAPDH in male albino rats. Also, our study was extent to investigate the toxicological effect of TCDD on sperm motility, sperm abnormalities and sperm cell concentrations. TCDD (doses (1/10, 1/20, 1/30 and 1/50 LD50/kg body weight, day after day) was administered orally to rats for 70 days. Twenty-four hours after the last treatment the animals were killed. Administration of TCDD decrease in serum testosterone and LH levels as well as the results indicated that TCDD induces down-regulation in mRNA expression StAR, PY450Scc and CYP19 in all treated groups in comparing with control group but No change in mRNA expression of testicular GADPH gene. Also, oral administration of TCDD for 70 days day after day, led to decrease sperm motility and sperm cell concentrations. In addition, histopathological exanimation of treated rats showed increase sperm abnormalities with compared to control group. Thus, the adverse effects of TCDD on the hormonal, gene expression and epididymal sperm were due to direct effect of TCDD on epididymis.