Effects of ovariectomy and dehydroepiandrosterone (DHEA) on vaginal wall thickness and innervation.
BACKGROUND
One mechanism by which low sexual steroid activity observed after menopause could cause sexual dysfunction is by deficient vaginal innervation. Recently, it has been shown that intravaginal administration of dehydroepiandrosterone (DHEA) could produce beneficial effects on sexual dysfunction in postmenopausal women.


OBJECTIVE
The goal of this study was to determine if DHEA could modify innervation in the rat vagina.


METHODS
The area occupied by the nerve fibers immunoreactive for protein gene product 9.5 (PGP 9.5), a panneuronal marker or tyrosine hydroxylase (TH), a sympathetic nerve fiber marker, in the lamina propria and muscular layers, respectively, as well as the total area of each of these 2 layers were measured by stereological analysis.


METHODS
The innervation of the rat vagina was examined 9 months after ovariectomy (OVX) compared to intact animals and treatment of OVX animals with DHEA (80 mg/kg). Four sections from each vagina (5 animals/groups) were immunostained.


RESULTS
In OVX animals, the lamina propria area was decreased to 44%, an effect which was reversed by DHEA to 69% of the intact value. OVX also caused a 59% decrease in the area of PGP 9.5 fibers, an effect which was prevented by DHEA, thus showing a 68% stimulatory effect of DHEA on the density of PGP 9.5 fibers in the lamina propria compared to OVX animals. Following OVX, the muscular layer area was decreased by 61%. DHEA treatment induced 118% and 71% increases in TH fiber area compared to OVX and intact animals, respectively. The density of TH fibers was 182% increased over intact controls by DHEA treatment of OVX animals.


CONCLUSIONS
The relatively potent stimulatory effect of DHEA on intravaginal nerve fiber density provides a possible explanation for the beneficial effects of intravaginal DHEA on sexual dysfunction observed in postmenopausal women.
Research Center in Molecular Endocrinology, Oncology and Human Genomics, Laval University, Quebec, QC, Canada. georges.pelletier@crchul.ulaval.ca
Georges
G
Pelletier
Johanne
J
Ouellet
Céline
C
Martel
Fernand
F
Labrie
D000282:Administration, Intravaginal; D000818:Animals; D003687:Dehydroepiandrosterone / Q000008:administration & dosage*; D005260:Female; D009092:Mucous Membrane; D010052:Ovariectomy; D010053:Ovary / Q000601:surgery*; D017698:Postmenopause; D051381:Rats; D017207:Rats, Sprague-Dawley; D012735:Sexual Dysfunction, Physiological / Q000188:drug therapy*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase / Q000378:metabolism*; D014621:Vagina / Q000033:anatomy & histology / Q000187:drug effects* / Q000294:innervation
D003687:Dehydroepiandrosterone; D014446:Tyrosine 3-Monooxygenase; C489034:UCHL1 protein, rat; D043222:Ubiquitin Thiolesterase