Fluoxetine is used in the management of depression, anxiety and other mood disorders by increasing serotonin levels in the brain and can cause sexual side effects by changing the homeostasis of sex hormones and increasing oxidative stress. Since many men who take fluoxetine are of reproductive age and sperm are exposed to fluoxetine for a considerable time, this study aimed to examine the in vitro effects of fluoxetine on human sperm biochemical markers and sperm parameters. Semen samples from 30 fertile men were divided into three groups: a positive control group, a negative control group and a fluoxetine-treated group. We investigated sperm parameters, mitochondrial membrane potential (MMP), acrosome reac- tion, DNA fragmentation, chromatin integrity, and the expression of CASPASE8, CASPASE9, BAX, and BCL2 genes and proteins. Data were analyzed using repeated measures analysis. The results showed that the average percentage of motil- ity, viability, MMP, acrosome and chromatin integrity, total antioxidant capacity (TAC) level, and BCL2 gene and protein expression in the fluoxetine group were significantly reduced compared to the positive and negative control groups. While the average percentage of non-progressive motility, sperm DNA fragmentation, malondialdehyde (MDA) level, reactive oxygen species (ROS), gene and proteins expression of CASPASE8, CASPASE9 and BAX increased significantly. This study suggests that fluoxetine may impair sperm quality by increasing the expression of apoptotic genes, proteins, and oxidative stress. Therefore, careful management of fluoxetine in treating depression is crucial, especially in men of reproductive age, due to its potential sexual side effects.
