Objective To investigate the changes of antioxidant enzyme activities in testis of SD rats after neonatal exposure to 3, 4-benzo(a)pyrene.
Methods The neonatal rats were treated with benzo(a)pyrene in corn oil by gavages at doses of 0, 5, 10 and 25 mg/kg from postnatal day 1 to day 7. They were sacrificed at postnatal day 8, 35 and 90. Organ weights, daily sperm production, enzyme activities of superoxide dismutase (SOD) and catalase (CAT), and CYP1A1 gene expression levels of testis were determined at postnatal day 8, 35 and 90.
Results CYP1A1 gene expressions in exposed groups were induced in a dose-dependent manner at postnatal day 8, and that of the 10 and 25 mg/kg groups were significantly higher than that of the controls (P < 0.05), but there was barely no CYP1A1 gene expression in groups at postnatal day 35 and 90. At postnatal day 8, SOD enzyme activities in 25 mg/kg group were increased significantly than that in the controls (P < 0.05); and CAT enzyme activities were increased with exposure doses; at postnatal day 35, the activities of both SOD and CAT decreased significantly than that of the controls (P < 0.05); at postnatal day 90, there was significant difference in neither SOD nor CAT enzyme activities between exposure groups and controls; and the number of daily sperm production of 10 and 25 mg/kg groups decreased significantly (P < 0.05).
Conclusion Neonatal exposure to benzo(a)pyrene altered activities of SOD and CAT enzymes in testis, and decreased daily sperm production.
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