Surgical menopause impact on vaginal mechanical properties

Area of Science:

• Biomedical Engineering
• Reproductive Biology
• Tissue Mechanics

Background:

• Menopause alters pelvic floor biomechanics, potentially leading to pelvic organ prolapse.
• Limited research exists on menopause and aging's effects on vaginal tissue viscoelasticity.

Purpose of the Study:

• To investigate the impact of surgical menopause (ovariectomy) and aging on the biomechanical properties of rat vaginal tissue.
• To compare the effects of ovariectomy versus natural aging on vaginal tissue viscoelasticity.

Main Methods:

• Used 21 female Long-Evans rats divided into Sham surgery, ovariectomy (OVX), and aged groups.
• Performed unconfined compression tests (stress relaxation and ramp compression) on vaginal tissue samples.
• Analyzed data to determine instantaneous modulus, equilibrium modulus, relaxation time constant (tau), and tangent modulus.

Main Results:

• OVX animals showed significantly lower instantaneous and equilibrium moduli compared to Sham and Aged groups.
• Sham animals exhibited a longer relaxation time constant (tau) than OVX and Aged animals.
• OVX animals presented the lowest tangent modulus, indicating reduced tissue stiffness.

Conclusions:

• Surgical menopause (OVX) has a more pronounced effect on vaginal tissue biomechanical deterioration than chronological aging.
• These findings highlight the significant biomechanical changes in vaginal tissue following ovariectomy, relevant to pelvic organ prolapse risk.