Expression of the apoptosis regulatory gene family in the long-term in vitro cultured human cumulus cells

Abstract Human cumulus cells (CCs) play a key role in the regulation of ovarian follicle maturation and oocyte fertilization. They influence the oocyte development by transferring the various molecules via the specific gap junction proteins, also known as the connexins, which provide a direct transmembrane connection between the oocyte and CCs. The human CCs were obtained in the patients diagnosed with infertility, who underwent the procedure of the controlled ovarian stimulation, and the following in vitro fertilization to elucidate the possible involvement of the CCs in the regulation of the fertilization and oocyte aging. Collected samples were long-term cultured and harvested after 7, 15, and 30 days of cultivation. Afterward, we assessed the relative expression of the following apoptosis regulatory genes - BAX, CASP9, and TP53 - using the RT-qPCR method. We noted a decrease in the expression of all above-mentioned genes in the samples harvested after 15 and 30 days, in reference to 7 days in vitro cultured CCs. In summary, our results provide precious insight into the dynamics of changes and confirm the continuous expression of the proapoptotic genes – BAX, CASP9, and TP53 in the long-term cultured CCs. Running title: Apoptotic gene expression in the human cumulus cells