Rabbit as an Aging Model in Reproduction: Advanced Maternal Age Alters GLO1 Expression in the Endometrium at the Time of Implantation

Advanced maternal age is associated with adverse pregnancy outcomes and the decline of female fertility in mammals. A potential reason for reduced fertility is metabolic changes due to protein modifications by advanced glycation end products. To elucidate the aging process in female reproduction, we analysed a key enzyme for detoxification of reactive dicarbonyls, the glyoxalase 1 (GLO1), in reproductive organs and blastocysts of young and old rabbits at the preimplantation stage. At day 6 post coitum, uterine, oviductal, ovarian tissue and blastocysts from young (16–20 weeks) and old rabbits (>108 weeks) were characterised for GLO1 expression. GLO1 amounts, enzymatic activity and localisation were quantified by qPCR, Simple Western, activity assay and immunohistochemistry. The GLO1 enzyme was present and active in all reproductive tract organs in a cell-type-specific pattern. Ovarian follicle and uterine epithelial cells expressed GLO1 to a high extent. In tertiary follicles, GLO1 expression increased, whereas it decreased in the endometrium of old rabbits at day 6 of pregnancy. In blastocysts of old animals, GLO1 expression remained unchanged. In early pregnancy, advanced maternal age leads to modified GLO1 expression in ovarian follicles and the endometrium, indicating an altered metabolic stress response at the preimplantation stage in older females.