Effects of cortisol on testicular apoptosis in goldfish (Carassius auratus)

Apoptosis is a programmed cell death that has been attributed to theaction of stress hormones, such as cortisol. We investigated the in vitro effect ofcortisol in goldfish (Carassius auratus) mature (GSI: 2٫75-4٫65) or immature (GSI: 1٫94-2٫4) testes. Testes were taken out and transferred into culture medium (M 199), cut into 20μm thick slices and supplemented with fetal bovine serum (FBS), addeddifferent doses of cortisol (0, 50, 100, 200, 400, 750 and 800 ng/ml) and incubatedfor 24h, 48h or 72h at 18°C. Samples were rinsed and homogenized with phosphatebuffered saline (PBS) after incubation period. Duplicates or triplicates processed forcaspase-3 activity. The results showed a significant increase in caspase-3 activity inimmature testes after 72h treatment with 750ng/ml of cortisol (P<0٫05), and also at400ng/ml (P<0٫05). In contrast, no significant differences were observed betweennon-treated and cortisol-treated samples from mature goldfish testes. In this studywe have demonstrated, for the first time that the stress hormone cortisol inducesapoptosis in the goldfish testis in a stage-specific manner (immature testis).