Efeitos do citrato de clomifeno, letrozol e estradiol sobre apoptose em células do cumulus oophorus humano

Abstract

Clomiphene citrate (CC) and letrozole (LE) are ovulatory stimulants that, despite high ovulation rates, achieve low pregnancy rates. This study aimed to investigate the in vitro effects of CC and LE, alone or in combination with estradiol (E), on apoptosis in human cumulus cells. We performed a controlled prospective study using primary cumulus cell cultures from patients undergoing in vitro fertilization (n=22). Giemsa stain and alpha-inhibin immunocytochemistry was used to assess cell culture purity and morphology. Cell viability was evaluated by MTT assay, cell cycle status by flow cytometry, and Caspase-3, Bax and superoxide dismutase 2 (SOD-2), and S26 gene expression by real-time polymerase chain reaction (qPCR). Cells were treated for 24 hours in 5 conditioned media: CC, CC + E, LE, LE + E and control. None of the treatments affected cell viability, but LE reduced the mean percentage of cells in the S phase compared to control (24.79 versus 21.70, p=0.0014). CC treatment increased mRNA expression of Bax (4 fold) and SOD-2 (2 fold), which was reversed by co-treatment with E. SOD-2 expression increased in cells treated with LE compared to control (4 fold), which was also reversed by E. These findings suggest that CC and LE do not significantly affect the viability of human cumulus cells. Still, the expression of genes involved in apoptosis was modulated by these drugs alone and in association with E, suggesting that CC and LE may have direct effects on cumulus cells beyond their known mechanisms of action.