Abstract

Highlights

• NaF exposure triggered testicular apoptosis and sex hormonal disruption.
• NaF exposure increased the expression of ER stress mediators in testis of rat.
• NAC pretreatment attenuated IRE1?-JNK-mediated apoptosis induced by NaF.
• The alteration of Nrf2-dependent redox homeostasis was involved in the protective effect of NAC against NaF-induced testicular apoptosis.

We previously investigated excessive fluoride exposure elicited intracellular endoplasmic reticulum (ER) stress and led to Sertoli cells dysfunction in vitro. However, the mechanisms underlying fluoride-mediated male reproductive damage in vivo remain largely unknown. Considerable evidence has now revealed ER stress is closely linked with testicular oxidative damage. Hence, we aimed to explore whether ER stress signaling was involved in the testicular protective effects of antioxidant N-acetylcysteine (NAC) against testicular apoptosis induced by fluoride. Male SD rats were oral gavaged with sodium fluoride (NaF) for 7 weeks to induce fluorosis. The animals were pretreatment with or without NAC (150?mg/Bw•d). Our results demonstrated that sub-chronic NaF exposure triggered testicular apoptosis and sex hormonal disturbance in pituitary-testicular (PT) axis, promoted oxidative stress and the expression of ER stress mediators. Antioxidant NAC, however, prevented NaF-induced testicular apoptosis accompanied by activating Nrf2-mediated antioxidant potential. Simultaneously, NAC pretreatment downregulated XBP1 splicing, reduced JNK phosphorylation and further blocked cleavage of caspase-3, all these might contribute to the inhibition of testicular cell apoptosis. Collectively, the present results suggested that prolonged administration of NAC preserved testicular function and normalized sex hormonal disruption induced by NaF via the inhibition of Nrf2-associated oxidative damage and Ire1?-JNK-mediated apoptosis in rat testis.

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