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

Abstract

Background and aims: 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.

Materials and methods: 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.

Results: 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.

Conclusions: 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.