Expression of Apoptosis Regulator Proteins Bcl-2 and Bad in Rat Ovarian Follicular Apparatus during Recovery after Extreme Hypothermia

The expression of molecular and cellular regulators of apoptosis (proapoptotic protein Bad and antiapoptotic protein Bcl-2) was measured in the follicular apparatus of rat ovaries during the recovery period (days 7 and 14) after hyperthermia (up to rectal temperature 43.5°C). The Bcl-2/Bad index was calculated. The expression of Bcl-2 in the follicular apparatus of rat ovaries increased on day 7 after the exposure. The Bcl-2/Bad index also increased, which suggests that the development of apoptosis by the mitochondrial pathway in follicles was limited at this term after hyperthermia. On day 14 after hyperthermia, the area of immunohistochemical staining for the antiapoptotic protein Bcl-2 significantly decreased in cells of the ovarian follicular epithelium, but the expression of the proapoptotic protein Bad significantly increased; these changes led to a decrease in Bcl-2/Bad index, which attested to weakening of the antiapoptotic defense and activation of oocyte apoptosis by the mitochondrial pathway.