Study: vaginal and clitoral tissue changes with oestrogen levels (rabbits)

Lower levels of oestrogen found at menopause appears to negatively impact female sexual arousal by causing changes in the tissue responsible for engorgement.

The study’s goal was to examine the impacts of circulating levels of oestrogen on the hemodynamics

Hemodynamics: an element of cardiovascular physiology that deals with the forces of the heart in circulating blood. In observable terms to a practitioner, it looks like blood pressure and blood flow values at certain key points around the system.

Hemodynamic disorders include hypertension and congestive heart failure] mechanism (blood pumping behaviour) of vaginal and clitoral engorgement, and the structure of the vaginal and clitoral cavernosal tissue, in rabbits.

The study

Fifteen white rabbits were divided into three groups of five rabbits: the control group, the bilateral oophorectomy (ovaries removed) group, and the bilateral oophorectomy undergoing subcutaneous oestrogen injections.

After six weeks:

• 17 beta-estradiol was measured
• Blood pressure monitored
• Vaginal and clitoral cavernosal blood flow measured before and after pelvic nerve stimulation
• Cross-sections of the clitoris and vagina examined

Findings:

• Significant decrease in 17 beta-estradiol in the group with ovaries removed compared with the control and oestrogen-replacement groups
• Nerve stimulation-induced peak vaginal and clitoral intracavernosal blood flow in the oophorectomy (ovaries removed) group were significantly less than those in the control or oestrogen-replacement group.
• Under closer inspection, there was marked thinning of the vaginal epithelium, less submucosal microvasculature, and diffuse fibrosis in the clitoral cavernosum in the oophorectomy group, but this was not apparent in the oestrogen supplement and control groups.
• The percentage of clitoral cavernosal smooth muscle in the oophorectomy group was significantly decreased compared with the control and oestrogen-replacement groups.

What does this mean?

This study, according to the researchers, show that a decline in circulating oestrogens impairs the hemodynamic mechanism of vaginal and clitoral engorgement. This leads vaginal and clitoral tissues to suffer changes.

Ultimately, these changes may play a role in the development of female sexual arousal dysfunction in menopausal and oestrogen-impaired women.

References

K Park, K Ahn, S Lee, S Ryu, Y Park and K M Azadzoi, Decreased circulating levels of estrogen alter vaginal and clitoral blood flow and structure in the rabbit, International Journal of Impotence Research (2001) 13, 116-124