Effect of glycine on recovery of bladder smooth muscle contractility after acute urinary retention in rats.
OBJECTIVE
To investigate the effects of glycine on the recovery of bladder smooth muscle contractility after acute urinary retention.


METHODS
Bladder overdistension was induced in Sprague-Dawley rats by an infusion of saline (twice the threshold volume), maintained for 2 h. From 15 min before emptying of the bladder until 2 h after, saline or glycine solution was infused i.v. At 30 min, 2 h and 1 week after bladder emptying, samples of bladder tissue were taken for muscle strip study, malondialdehyde (MDA) assay, ATP assay, Western blotting for apoptosis-related molecules (Bcl-2, Bax, Caspase-3), and histological analysis including terminal deoxynucleotidyl transferase-mediated nick-end labelling staining. The results were compared among normal control, saline-treated and glycine-treated rats.


RESULTS
In the glycine-treated group, muscle strip contractile responses induced by electrical-field stimulation and carbachol were both significantly greater at 1 week after bladder emptying than in the saline-treated group. The results of the ATP assay appeared to correspond with those of the muscle strip study. The saline-treated group had significantly higher MDA levels at 30 min after bladder emptying than the glycine-treated group. At 2 h after bladder emptying, there was significantly more apoptosis and greater leukocyte infiltration in the saline-treated group than in the glycine-treated group. While pro-apoptotic Bax and caspase-3 were down-regulated, Bcl-2 was up-regulated in the glycine-treated group.


CONCLUSIONS
Glycine infusions might improve the contractile responses of bladder smooth muscle after acute urinary retention by reducing oxidative damage and apoptosis.
Hong
Sung K
SK
Department of Urology, Seoul National University College of Medicine, Seoul, Korea.
Son
Hwancheol
H
Kim
Soo W
SW
Oh
Seung-June
SJ
Choi
Hwang
H
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D005260:Female; D005998:Glycine / Q000494:pharmacology*; D018684:Glycine Agents / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D001743:Urinary Bladder / Q000187:drug effects*; D016055:Urinary Retention / Q000503:physiopathology*
D018684:Glycine Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D005998:Glycine