The extracellular reactive oxygen species levels in primary in vitro culture of human ovarian granulosa and cumulus cells

In the female reproductive tract, reactive oxygen species (ROS) may exert physiological and pathophysio-logical effects. Although ROS play an essential role as the signaling molecules, their excessive accumulation contributes to the pathogenesis of many reproductive processes. In the ovarian follicle, ROS affect multiple physiological processes, including oocyte maturation and fertilization. However, a lack of studies showing to which extend ovarian granulosa and cumulus cells can contribute to the development of oxidative stress within the ovarian follicle. In the presented research, the extracellular ROS accumulation level was investigated using GCs and CCs primary in vitro cultures. The obtained results demonstrated a steady decrease in extracellular ROS level during GCs primary culture. By contrast, ROS concentration in CCs conditioned medium increased gradually between the first and the seventh days of culture. The observed changes may reflect the proliferation status and metabolic activity of GCs and CCs during in vitro culture. Additionally, the elevated ROS level at respective points of time could occur as a consequence of culture in atmospheric oxygen. The distinct function and localization within the ovarian follicle may explain the differences between GCs and CCs oxygen metabolism.

Running title: Reactive oxygen species in primary culture of human follicular cells