The role of N6-methyladenosine modification in benzene-induced testicular damage and the protective effect of melatonin.

Benzene is a universal ambient pollutant. Population-based studies have shown that benzene exposure affects male fertility. However, the mechanism of benzene-induced reproductive toxicity is unknown. Here, we established a dynamic inhalation model and exposed C57BL/6J mice to 0, 10, and 50 ppm benzene (6 h/day, 6 days/week, 7 weeks). Our study revealed that benzene exposure caused testicular injury, including structural damage to spermatogenic tubules, reduced semen quality, and decreased testosterone levels. In addition, the decrease in the global level of N6-Methyladenosine (m6A) and the change of m6A important regulatory enzymes in mice testes suggested that m6A was involved in the benzene-induced testicular injury. Further genome-wide m6A methylation analysis showed that 1469 differential m6A peaks were present in the testes of control and benzene groups, indicating that benzene exposure modulated m6A methylation in testes. Furthermore, the comprehensive analysis of m6A-sequencing and transcriptome revealed that hypermethylated Rara and its consequent reduced expression impaired the sperm production process. In particular, melatonin alleviated benzene-induced testicular injury by modulating m6A-related genes. Overall, our research provides a new idea and fundamental knowledge into the possible mechanisms of m6A modifications in benzene-induced testicular impairment, as well as a new experimental basis for benzene-induced male fertility therapy.