Confocal laser scanning microscopy analysis of bioenergetic potential and oxidative stress in fresh and frozen-thawed human ovarian tissue from oncologic patients

Abstract

To evaluate the effectiveness of a bioenergy/oxidative stress assessment based on confocal laser scanning microscopy (CLSM) in association with morphology and ultrastructure analyses based on light microscopy (LM) and transmission electron microscopy (TEM), to monitor the preservation status of cryopreserved human ovarian tissue from cancer patients. Prospective study. University hospital. Fourteen young cancer patients. Human ovarian tissue biopsy, slow freezing/rapid thawing, LM, TEM, CLSM assessment of mitochondrial distribution and activity, and intracellular reactive oxygen species (ROS) localization and levels. In tissue examined before and after slow freezing/rapid thawing, follicular and stromal LM-based score of morphologic damage, ultrastructure, mitochondrial distribution pattern, reactive oxygen species (ROS) localization; mean ± standard deviation of stromal mitochondrial activity and ROS levels. Severe (n = 6 patients), slight (n = 6 patients), or no (n = 2 patients) LM/TEM-based damage was found in fresh tissue. After freezing/thawing, no further morphologic/ultrastructural alterations were found; however, statistically significant reductions, increases, or no changes in mitochondrial activity and ROS levels were found in severely, slightly, and undamaged tissue, respectively. Bioenergy/oxidative functional damage was found in tissue with severe LM/TEM-assessed damage. In tissue with slight LM/TEM-assessed damage, the CLSM-based bioenergy/oxidative stress assessment was the only test that allowed discrimination between tissue that had been better (low/no difference) or worse preserved (significant differences).