Increased intraovarian levels of noradrenaline and NGF precede the follicular changes in the rat ovary at the end of reproductive period
Alfonso H Paredes, Eric Acuña, Romina Fornes & Hernan E Lara
Reports in the literature have demonstrated an increased number of nerve fibers and the presence of a follicle development similar to polycystic ovary during perimenopausal ovary in women. Since differentiation, proliferation and growth of nerves depends of nerve growth factor (NGF), changes in the content of nerves fiber could be preceded by increases in NGF and p75 neurotrophin receptor (p75NTR). Our purpose was to evaluate the changes in noradrenaline (NA) at the celiac ganglion at the ovary and plasma levels through the establishment of the anovulatory condition associated with age. We also measured NGF and p75NTR mRNA, in relation to the changes in ovarian morphology. We used Spraque-Dawley rat between at 6 and 16 month old. The NA was determined by HPLC, NGF proteins by ELISA and NGF and p75NTR mRNA by real time PCR. The results show that plasma NA content decreased gradually with age, while in the ovary NA content increased at ageing. NA content in celiac ganglion only decreased after 12 month old,. The local changes of NA are accompanied by an intraovarian increase of NGF mRNA. Nevertheless, the content of p75NTR not changed. The ovarian morphological analysis shows after rat 12 month old present an increased number of type III, luteinized as cystic follicles. In conclusion, the increase of cystic and type III follicles in the rat aging, after 12 month old and at the end of reproductive function are preceded by a local increase of intraovaric neurotrophin and nerves sympathetic activity.