“Efeito da suplementação dietética de arginina, na dosagem de hidroxiprolina da parede abdominal e bexiga urinária de ratos urêmicos”

Abstract

Arginine, a semi-essencial aminoacid, has been involved in many metabolic and immunologic effects, including the healing process. The arginine supplementation has shown benefits on wound healing. Uremia is a condition related to wound healing impairment. The objective of the present study was to evaluate the effects of arginine supplementation on wound healing of abdominal wall and bladder in uremic rats, through hydroxyproline concentration assays. Methods: Thirty two adult male Wistar rats, with a mean weight (± sd) of 314.9±26g, were divided in cages of eight animals. All rats had free access to water and standard rat chow diet. They were weighted at the beginning of the experiment and every seven days. The animals were randomized into four groups: two uremic groups (UREMIC ARG and UREMIC ALA with 8 animals each) were formed by rats who were submitted to total right nephrectomy followed by partial left nephrectomy, and two groups of control animals (SHAM ARG and SHAM ALA with 8 animals each) who underwent a sham operation consisted of surgical manipulation without nephrectomy. The two ARG groups received through orogastric tube, a daily supplemented diet containing 1.5g/Kg/day of arginine whereas the two ALA groups received alanine (control aminoacid) at the same manner and dose. At the beginning of the experiment the animals were submitted to surgical procedure to create the uremic model (nephrectomy), on the 7th postoperative day the oral supplementation was initiated, at the 14th postoperative day the surgical procedure to produce scars was done (laparotomy and vesicotomy). The animals were sacrificed at the 21st postoperative day, dosage of urea and creatinine was done and specimens of abdominal wall and bladder were taken to hydroxyproline concentration assays (a marker of wound healing). Results: There were no differences in body weight curve between the groups. There were dehiscence cases only in the alanine supplemented animals. Hydroxyproline values from the abdominal wall was significantly higher in SHAM ARG group compared to both UREMIC ARG (1.18±0,11g/mg vs. 0,7±0,22g/mg, p=0.04) and UREMIC ALA groups (1.18±0,11g/mg vs. 0,86±0,06g/mg, p=0.04). Hydroxyproline values from the bladder was higher in SHAM ARG group compared to UREMIC ALA group (0.9±0,12mg/g vs. 0.6±0,05mg/g, p=0.03). Conclusion: Arginine supplementation increases hydroxyproline concentration of bladder in uremic rats and of abdominal wall in non-uremic rats.