Reproductive toxicity and parental transmission effects of 4-methylbenzylidene camphor (4-MBC) exposure in adult zebrafish

4-methylbenzylidene camphor (4-MBC), a commonly used UV absorber, is frequently detected in aquatic environment. So far the reproductive toxicity of parental 4-MBC exposure and its effects on gonadal development in offsprings are not clear. In the present study, male and female adult F0 zebrafish were exposed to 100 nM 4-MBC for 14 consecutive days. Our data showed that 4-MBC exposure resulted in gonadal damage in the parental gonads and decreased egg production in females and sperm viability in males. In addition, exposure to 4-MBC resulted in increased levels of estradiol (E2), follicle stimulating hormone (FSH), and luteinizing hormone (LH) in females and decreased testosterone (T) in males, suggesting the estrogenic and antiandrogenic effects of 4-MBC. Parental 4-MBC exposure did not change the hatchability and mortality of the F1 generation, but caused significantly decreased heart rate and gonadal developmental retardation in 60 dpf fish by interfering with the HPG axis. Therefore, 4-MBC exposure to adult zebrafish caused gonadal damage and reduced reproductive performance in the parental generation, which was sex-dependent and caused intergenerational toxicity to the F1 generation. The present study provides new insights into the ecological risks of 4-MBC and its potential contribution to adverse reproductive outcomes in humans.

4-Methylbenzylidene camphor (4-MBC); Gonadal damage; Intergenerational transmission effect; Offspring development; Reproductive toxicity.