[Effects of long-term replacement therapy of compound nylestriol tablet or low-dose 17 beta-estradiol on the expression of nerve growth factor in OVX rat hippocampal formation].

To determine the effects of long-term estrogen deficiency and replacement therapy of compound nylestriol tablet or low-dose 17 beta-estradiol on the expression of nerve growth factor (NGF) in rat hippocampal formation. Fifty 7 month-old female Sprague-Dawley rats were randomly divided into 5 groups: normal control, sham operated (SHAM), ovariectomized (OVX), OVX plus 17 beta-estradiol (OVX/ERT), and OVX plus compound nylestriol tablet (OVX/NL) groups. Immunohistochemistry of NGF was used to quantitatively determine the levels of expression of NGF using cell counting and imaging system in ovariectomized rat hippocampal formation. The number and optical density of NGF-positive neurons of all hippocampal subregions and dentate gyrus in OVX rats were obviously lower than those of the normal control, SHAM, OVX/NL, and OVX/ERT rats. Long-term estrogen deficiency can lead to a decrease of NGF expression in hippocampal formation, while the replacement of low-dose 17 beta-estradiol or compound nylestriol tablet can equally preserve the expression of NGF to a normal level, showing a neurotrophic effect of estrogen.