The effect of hyperstimulation on transforming growth factor b1 and b2 in the rat uterus: possible consequences for embryo implantation
Date
2008-10-15T12:02:44Z
Authors
Jovanovic, Aleksandra
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Abstract
Ovarian hyperstimulation is achieved through ovarian gonadotropin
stimulation, and thus associated with supraphysiological levels of
oestrogen and progesterone. To investigate the effects of exogenous
gonadotropins on the expression of TGF b1 and TGF b2, which have
been recognized as possible modulators of many endometrial
functions, FSH and hCG were superimposed upon the normal hormonal
milieu of the cycling rat, prior to mating. Endometrial tissue was
collected at 4.5, 5.5 and 6.5 days after mating. ELISA was performed
to estimate blood oestrogen and progesterone levels and
immunohistochemistry was undertaken to localize TGF b1 and TGF b2 in
the uterine endometrium. Apart from the known detrimental effects of
hyperstimulation on gross morphology, hormone levels and
endometrial histology, the hyperstimulation was also found to affect
TGF b expression. An increase in the expression of TGF b2 was distinct
in the glandular epithelium of the hyperstimulated animals, while
regionalized expression of both TGF b1 and TGF b2 was prominent in
the stroma. In conclusion, hyperstimulation affects the expression of
both TGF b1 and TGF b2, which may contribute to the disruption of the
endometrial environment required for successful embryo implantation.
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Keywords
growth factor, rat uterus, embryo, implantation