Estrogen and ghrelin decrease cytoplasmic expression of p27^kip1, a cellular marker of ageing, in the striated anal sphincter and levator muscle of ovariectomized rats

A study was carried out to investigate the effect of estrogen and/or ghrelin on the cellular marker of ageing, p27^kip1, in pelvic floor muscles of ovariectomized rats. Virgin Wistar rats (13 months old) underwent ovariectomy followed (1 month) by 42 daily intraperitoneal 17-beta; estradiol (10 μg/kg), ghrelin (2 μg/kg), both hormones, or placebo vehicle (n=6×4 groups). Six more age-matched animals underwent sham surgery without ovariectomy. Cytoplasmic expression of p27^kip1 in the striated urethral and anal sphincters and levator muscle was measured by Western blot analysis in all animals (n=30). p27^kip1 signal intensity significantly increased postovariectomy in all muscles compared to sham animals. In the anal sphincter and levator, signal intensity decreased to sham levels with ghrelin or estrogen and decreased further after estrogen or ghrelin and estrogen/ghrelin administration. Urethral sphincter signal intensity decreased without reaching sham levels after drug administration. Estrogen and/or ghrelin replacement reverses the ovariectomy-induced exacerbation of biochemical cellular ageing in the anal sphincter and levator muscle of middle-aged rats.