The effect of hyperstimulation on transforming growth factor b1 and b2 in the rat uterus: possible consequences for embryo implantation

摘要

Ovarian hyperstimulation is achieved through ovarian gonadotropinudstimulation, and thus associated with supraphysiological levels ofudoestrogen and progesterone. To investigate the effects of exogenousudgonadotropins on the expression of TGF b1 and TGF b2, which haveudbeen recognized as possible modulators of many endometrialudfunctions, FSH and hCG were superimposed upon the normal hormonaludmilieu of the cycling rat, prior to mating. Endometrial tissue wasudcollected at 4.5, 5.5 and 6.5 days after mating. ELISA was performedudto estimate blood oestrogen and progesterone levels andudimmunohistochemistry was undertaken to localize TGF b1 and TGF b2 inudthe uterine endometrium. Apart from the known detrimental effects ofudhyperstimulation on gross morphology, hormone levels andudendometrial histology, the hyperstimulation was also found to affectudTGF b expression. An increase in the expression of TGF b2 was distinctudin the glandular epithelium of the hyperstimulated animals, whileudregionalized expression of both TGF b1 and TGF b2 was prominent inudthe stroma. In conclusion, hyperstimulation affects the expression ofudboth TGF b1 and TGF b2, which may contribute to the disruption of theudendometrial environment required for successful embryo implantation.