Abstract

BACKGROUND--Nucleoside-nucleotide mixture has been shown to improve gut morphology and reduce the incidence of bacterial translocation in protein deficient mice. AIMS--To compare the reparative effect of nucleoside-nucleotide mixture and their individual components on maintenance of gut integrity and bacterial translocation based on their differential metabolism and utilisation. METHODS--ICR (CD-1) mice were randomised into eight groups of 10 animals each and fed 20% casein diet (control), protein free diet, or protein free diet supplemented with 3 M cytidine, uridine, thymidine, inosine, guanosine monophosphate, or nucleoside-nucleotide mixture for four weeks. On the fourth week, each mouse was injected lipopolysaccharide intraperitoneally (50 micrograms/500 microliters) and the incidence of bacterial translocation, caecal bacterial populations, and the ileal histology, noted 48 hours later. RESULTS--The death rate in the control group was 40% compared with 10% in the nucleoside-nucleotide mixture and 20% each in the individual components groups, respectively. Bacterial translocation to the mesenteric lymph node did occur in 100% of the surviving mice fed the control diet in comparison with 44% (nucleoside-nucleotide), 50% (cytidine), 75% (thymidine), 75% (uridine), 63% (inosine), and 63% (guanosine monophosphate). Histologically, the damage to the gut was more distinct in the protein free diet group. Villous height, crypt depth, and wall thickness in the nucleoside-nucleotide mixture group mean (SEM) (5.01 (0.34); 0.87 (0.14); 0.33 (0.10)), were respectively, higher compared with the protein free diet (3.34 (0.34); 0.61 (0.03); 0.18 (0.04)) group. In the cytidine group, crypt depth (0.86) (0.08)), and wall thickness (0.30 (0.002)) were higher. The same measurements in the components groups tended to be higher than the protein free diet group. Caecal bacterial populations were, however, similar in all groups. CONCLUSIONS--These results suggest that dietary nucleosides and nucleotides are essential nutrients for intestinal repair; nucleotides or cytidine provide a better response.