Effects of hyperprolactinemia on the tibial epiphyseal plate of mice treated with sex hormones.

The aim of this study was to evaluate the effects of metoclopramide-induced hyperprolactinemia on the tibial epiphyseal plate of hormone-treated oophorectomized mice. For this purpose, 18 animals with intact ovaries were allocated to two groups, M (metoclopramide) and V (vehicle). One hundred and eight oophorectomized animals were allocated to 12 subgroups: Oophx/V (vehicle); Ooph/M (metoclopramide); Oophx/V + E (vehicle + estradiol); Oophx/M + E (metoclopramide + estradiol); Oophx/V + P (vehicle + progesterone); Oophx/M + P (metoclopramide + progesterone); Oophx/V + T (vehicle + testosterone); Oophx/M + T (metoclopramide + testosterone); Oophx/V + E + P (Vehicle + estradiol + progesterone); Oophx/M + E + P (metoclopramide + estradiol + progesterone); Oophx/V + E + P + T (vehicle + estradiol + progesterone + testosterone); Oophx/M + E + P + T (metoclopramide + estradiol + progesterone + testosterone). After a 50-day treatment was performed histomorphometric and immunohistochemical cell death analysis. In the epiphyseal plate of the hyperprolactinemic and/or oophorectomized animals, cell proliferation and bone formation decreased, inducing intensified cell death. In the sex steroid-treated animals, estrogen boosted cell proliferation; progesterone, bone formation and testosterone, both cell proliferation and bone formation. These findings suggest that oophorectomy and hyperprolactinemia changed epiphyseal plate morphology causing cartilage degeneration. Treatment with combined sex steroids may diminish such deleterious effects.