Modulation Effects of Reproductive Hormones on Oogenesis in a Collagenase-Induced Osteoarthritis Mouse Model

Background/Objectives: Osteoarthritis has been increasingly described as associated with systemic inflammation, raising the question of how it would affect fertility in young women with or without reproductive hormone administration. We studied oogenesis in mice with collagenase-induced osteoarthritis (CIOA) as a model system with fewer ethical limitations after estradiol (E2) or follicle-stimulating hormone (FSH) treatment. Methods: Oocytes have been isolated from mice subjected to various treatment regimens. The meiotic spindle, the chromatin, and the actin cap were fluorescently labeled and analyzed. Results: In addition to reduced maturation rates, specific oocyte abnormalities were registered when CIOA, FSH, or E2 were applied in isolation. Combined treatments showed that the spindle, chromatin, and actin cytoskeleton parameters were differently affected in oocytes from groups with CIOA treated by estradiol and those treated with FSH. Enlarged spindles, ooplasmic tubulin asters, aligned metaphases, and predominantly normal actin caps, often with an actin halo, were typical for groups with CIOA combined with estradiol. The groups with CIOA and FSH had slightly enlarged spindles, unaligned metaphases with degenerated chromatin surrounded by a cloud of depolymerized tubulin, and small actin caps. Conclusions: Our results show that experimental osteoarthritis with or without exogenous reproductive hormones negatively affects oogenesis, presumably due to systemic inflammatory factors making the ovarian microenvironment less capable of supporting oocyte maturation. Estradiol supplementation does not benefit oogenesis. FSH treatment induced cytoskeletal and chromatin abnormalities that presumably disturb the fertilization and development potential of affected oocytes. These data can have implications for assisted reproduction in cases of patients with osteoarthritis.