Effect of age on in vivo urinary bladder function in the rat

Area of Science:

• Urology
• Gerontology
• Physiology

Background:

• Aging is associated with physiological changes affecting various bodily functions.
• Micturition, the process of urination, is complex and can be influenced by age-related factors.
• Understanding age-related changes in micturition is crucial for identifying potential health issues.

Purpose of the Study:

• To investigate the effects of aging on micturition parameters in male Fischer 344 rats.
• To quantify changes in water intake, urine output, and micturition characteristics with age.
• To assess age-related alterations in intravesical pressure and bladder volume during micturition.

Main Methods:

• Male Fischer 344 rats of three age groups (5-7, 16-18, and 22-24 months) were studied.
• 24-hour water intake and urine output were measured using metabolic cages.
• Natural-fill cystometry was employed to evaluate intravesical pressure and bladder volume at micturition.

Main Results:

• Advancing age significantly increased 24-hour water intake and urine output.
• Older rats (22-24 months) showed a 39% increase in water intake and a 93% increase in urine output compared to younger rats (5-7 months).
• Increased urine output was attributed to greater volume per micturition and increased frequency, with significantly higher pressure at micturition (PAM) in older rats, but no change in bladder volume at micturition (BVM).

Conclusions:

• In vivo micturition function undergoes significant changes with age in male Fischer 344 rats.
• While no overt urological dysfunctions were observed, functional alterations suggest changes in micturition control mechanisms or bladder musculature.
• Further research is warranted to elucidate the specific mechanisms underlying these age-related micturition changes.