Role of l-glutamine and glycine supplementation on irradiated colonic wall

Abstract

Radiotherapy is frequently used for cancer treatment, but it may be associated with several complications. Thus, this study aimed to evaluate the role of L-glutamine and/or glycine supplementation on the colonic wall in rats submitted to abdominal radiation. Sixty adult Wistar rats were randomly divided into six groups: I-healthy, II (control)-irradiated rats without amino acid supplementation, III-irradiated rats with glycine supplementation, IV-irradiated rats with L-glutamine supplementation, V-irradiated rats with glycine supplementation 7 days before irradiation and with L-glutamine supplementation 7 days after irradiation, and VI-irradiated rats with L-glutamine supplementation 7 days before irradiation and with glycine supplementation 7 days after irradiation. Abdominal irradiation was employed with a dose of 1,000 cGy on the eighth day of the experiment. All animals underwent laparotomy on the 15th day for resection of a colonic segment for stereologic analysis. Parametric and nonparametric tests were used for statistical analysis, with the level of significance set at p<or=0.05. Control animals (group II) presented a significantly smaller total volume of colonic wall when compared to animals of groups I, III, IV, V, and VI. There was a significant increase in mucosal layer volume in the animals of group IV compared to animals of groups I, II, and III. Our findings suggest that L-glutamine and/or glycine supplementation is beneficial for the repair of the colonic wall of rats, but L-glutamine, with its trophic effects on the colonic mucosa, seems to exhibit better results.