RESUMEN
The CatSper gene family is known to be solely expressed in sperm cells and is possibly associated with sperm motility and penetration through the zona pellucida. Despite its vital role in male fertility, factors regulating its expression are not widely known. The present study aimed at evaluating the effects of dioxin on CatSper2 gene and protein expression, testicular histopathology, sperm quality and biochemical parameters in a mice model. The experiments were performed on 32 Naval Medical Research Institute male mice (2-3 months). The animals were divided into four groups in a random manner: (a) control; (b) dioxin 1; (c) dioxin 2; and (d) dioxin 3. The treatment groups received 0.1, 0.5 and 1 µg/kg of dioxin intraperitoneally every day for 2 weeks. Administration of dioxin significantly downregulated the CatSper2 gene and protein expression. A greater reduction in gene and protein expression was found at higher doses of dioxin. At the same time, sperm parameters, especially sperm motility and count, decreased in mice exposed to dioxin. The results of testicular histopathology showed necrotic degeneration and epithelium thickness reduction in the dioxin groups in comparison with the controls. Besides, oxidative stress increased in seminiferous tubules.