Reproductive toxicity of InP/ZnS QDs in male rare minnow (Gobiocypris rarus).

InP/ZnS quantum dots (QDs) stand out among cadmium-free alternatives for higher exciton Bohr radius and strong quantum confined effect. In this study, the reproductive toxicity and mechanism of InP/ZnS QDs at different concentrations in male Chinese rare minnows (Gobiocypris rarus) were investigated. The results showed that QDs in 800 nmol/L concentration group could enter the testes after 1 d of exposure and caused changes in the structure of the testes, including the scattered distribution of seminal vesicles, reduction in germ cells and vacuolation in some areas of interstitial cells. The expression levels of androgen receptor (Ar) and doublesex and mab-3 related transcription factor 1 (Dmrt1) and the tight junction protein-related genes β-catenin and occludin were upregulated in rare minnows. The sperm quality and ATP content of parents in the 800 nmol/L treatment group were significantly decreased. Continuous detection of the development of F1 generation embryos showed that parental exposure to InP/ZnS QDs reduced the heart rate and spontaneous movement frequency of F1 generation embryos, and the fertilization rate of the F1 generation in the 800 nmol/L treatment group was significantly reduced. In general, the sperm quality and testicular structure of adult rare minnows were not significantly affected by concentrations below 400 nmol/L. High-concentration InP/ZnS QDs exposure can damage the integrity of the blood-testis barrier (BTB) and cause reproductive damage to the parents of rare minnows, which will continue to the next generation and affect their development.