INTRAVENOUS ADMINISTRATION OF NUCLEOSIDES AND A NUCLEOTIDE MIXTURE DIMINISHES INTESTINAL MUCOSAL ATROPHY INDUCED BY TOTAL PARENTERAL-NUTRITION

Total parenteral nutrition (TPN) is associated with atrophic changes in the structure and function of the intestinal mucosa. Because rapidly renewing intestinal mucosal cells may require an external source of purines and pyrimidines for their optimal growth, it can be assumed that supplementation of nucleosides and a nucleotide mixture (OG-VI) during TPN may prevent the progression of mucosal atrophy by compensating for a relatively insufficient delivery from liver. To test that hypothesis, male Wistar rats receiving TPN for 7 days were divided into four groups according to different TPN solutions. Group C (n = 10) received a standard solution, group O (n = 10) received OG-VI in addition to the standard solution, and group G (n = 10) received a glutamine-rich TPN solution containing almost the same amount of calories and nitrogen as the standard solution. Group O+G (n = 10) received OG-VI in addition to the glutamine-rich solution. Various parameters were examined on the eighth day in the jejunal and ileal segments. The following significant changes in comparison with group C were observed: total wet weight of the jejunal segment in group O was significantly greater, as was mucosal wet weight of the jejunal and ileal segments in groups O and O+G; protein contents of the ileal segment in group O as well as the DNA content of the jejunal segment in group O increased significantly; and maltase activity of the jejunal segment in group O+G increased, as did the villus height of the jejunal segment in groups O and O+G and the villus height of the ileal segment in group G. Finally, proliferating cell nuclear antigen-positive cells in crypts of the jejunal segment in group O and group O+G increased significantly. The supplementation of OG-VI prevented the intestinal mucosal atrophic changes induced by TPN more effectively than did glutamine. The combined effect of OG-VI and glutamine was observed on the development of brush-border enzymes. Provision of an external source of purines and pyrimidines therefore has a supportive effect on intestinal mucosal growth during TPN.