The effect of cortisone on female zebrafish (Dania rerio): Reducing reproductive capacity and offspring survival rate.

Cortisone is a naturally occurring corticosteroid hormone known for its wide range of anti-inflammatory and immunosuppressive effects, and it is commonly found in various aquatic environments. Previous reports have shown that cortisone can have significant negative impacts on fish; however, its specific effects on fish reproduction have not been thoroughly investigated. In this study, female adult zebrafish were exposed to 0.0 (control), 3.9, 40.2, and 377.9 ng/L of cortisone for 60 days, and multiple endpoints were evaluated. The results showed that as the concentration of cortisone increased, there was an increase in the percentage of perinuclear oocytes and a decrease in the proportion of late-stage oocytes, indicating a stagnation in oocyte development. Additionally, female zebrafish exposed to cortisone exhibited decreased attraction to males and reduced mating intimacy. Furthermore, exposure to cortisone resulted in changes in the development and behavior of zebrafish embryos. At cortisone concentrations of 3.9 and 40.2 ng/L, fewer eggs were laid and the survival rate of fertilized eggs decreased. These observed effects are associated with abnormal transcription levels of genes (Star, Cyp11a1, Cyp17, Cyp19a, Cyp11b, Hsd11β2, Hsd17β3) related to the HPG axis. These findings provided new insights into understanding potential environmental risks associated with corticosteroids.