Microscopic study of fetal hypothalamic tissue transplanted into the third ventricle of senescent female rats

Abstract

As the female rat ages, her ovarian cycles become irregular and she ceases to ovulate. This aging process of reproductive function appears to be partially due to a neurodegenerative process in the hypothalamic areas responsible for the control of the anterior pituitary gland. There has been some success in recovery of function after transplantation of neural tissue in some cases of genetic neural deficits or in deficits due to lesions of the hypothalamus. This experiment was conducted to determine whether the senescent female rat will regain her ability to ovulate after fetal hypothalamic transplants. Here we describe the morphological development of the hypothalamic transplants.Basal hypothalamic or cortical (control) tissue from fetal rats at 17E were transplanted into senescent Sprague-Dawley female rats demonstrating the cessation of ovulation. Fetal tissue was mechanically dissociated and placed in artificial CSF. Ten μI aliquots of the transplant preparation were infused into the third ventricle of 6 experimental and 6 control animals with a 26 ga Hamilton syringe at a rate of 1 μl/min. The needle remained in place for 5 additional min before it was removed. Animals were monitored for vaginal cyclicity for 30 days. Cyclicity was partially restored in animals transplanted with hypothalamic but not cortical tissue.