Efeito da suplementação dietética de arginina na cicatrização das anastomoses colônicas em ratos

BACKGROUND: Arginine, a conditionally essential amino acid, participates in various physiological processes, particularly in wound healing and immune function. AIM: To evaluate the effect of oral supplementation of arginine on colonic healing in rats. METHODS: Forty-seven male adult Wistar rats, with an average weight of 345.45 ± 8.35 g were used. They were placed in collective cages in groups five or six animals. All received water and food ad libitum, were weighed every two days and randomized to receive supplementation by gavage with a 10% arginine solution (ARG group) or an isovolumetric, isocaloric and isonitrogenous (1, 5 g / kg / day) 10% amino acids solution (group AA) for seven days before the procedure and four after surgery. A third group received isovolumetric isotonic saline solution (group SSI). All rats were subjected to two end to end colonic anastomoses, one 3 cm distal to the ileocecal valve and another 5 cm distal from the first, in a single layer with monofilamentar nylon 5-0, and were sacrificed at 5 days post-surgery. At sacrifice, both anastomoses were resected, one was kept in a saline solution for traction measurements while the other was sent to pathology for analysis of collagen (total, mature and immature) and immunohistochemistry for the detection of myofibroblasts and neovascularization. We evaluated the body weight throughout the experiment. Statistical analysis was performed using the Student t test and Mann-Whitney test. RESULTS: The comparison of body weight in the three groups showed no significant difference in initial weights, but a difference was observed between the groups SSI and AA in final weight (324.7 g vs. 298g, P = 0.04). The tension strength was significantly higher in the AA group as compared to SSI (0.94 kgf / cm ² vs. 0.67 kgf / cm ², P = 0.04) but not when compared to the ARG group (0.94 kgf / cm ² vs. 0.70 kgf / cm ², P = 0.09). For the maximal tension strength there was a significant difference between the AA group and the SSI group (0.18 vs 0.13 kgf kgf, P = 0.04) but not when compared to the ARG group (0.18 vs 0.14 kgf kgf , P = 0.08). The total rupture strength of showed significantly higher values for the AA group as compared to the ARG group (0.10 vs 0.06 kgf kgf, P = 0.05) but not when compared to the SSI group (0.10 vs 0.09 kgf kgf, P = 0.54). There was no significant difference in the concentration of collagen subtypes I and III and also no difference in the collagen maturation index in the three groups. There was also no significant difference on the number of blood vessels (angiogenesis) or myofibroblasts by immunohistochemistry among the three groups. CONCLUSIONS: The administration of a solution containing 20 amino acids was more effective than arginine alone on the healing of colonic anastomoses in rats.