EFFECTS OF NUCLEOSIDES AND A NUCLEOTIDE MIXTURE ON GUT MUCOSAL BARRIER FUNCTION ON PARENTERAL-NUTRITION IN RATS

Background: We have previously reported that the addition of nucleosid es and a nucleotide mixture (OG-VI) to total parenteral nutrition (TPN ) prevents TPN-induced intestinal mucosal atrophy and results in incre ased intestinal cathepsin activities under TPN. The aims of the presen t study are to examine the effects of OG-VI on mucosal barrier functio ns and to clarify whether the intestinal cathepsins can be used as a n ew marker of mucosal barrier function. Method: Male Wistar rats were d ivided into three groups: FED (food ad libitum), TPN (a standard TPN s olution), and OG (OG-VI in addition to the TPN solution). Mucosal barr ier functions were analyzed by the lactulose/mannitol (L/M) test, muco sal ZO-1 messenger RNA level, and electron micrographs in the gut. Int estinal cathepsin B, Il, and L activities were also measured. Results: The L/M ratio for TPN was much higher than that for FED. Only lactulo se excretion was significantly reduced by OG-VI. The intercellular spa ces of the mucosal cells for TPN were significantly wider than those f or FED, but were reduced in size by the addition of OG-VI. All catheps in activities of the ileum were higher for TPN than for FED, whereas O G showed no increase. Conclusion: OG-VI contributes to the improvement of gut mucosal barrier function. Intestinal cathepsin activities can be used as a new marker of mucosal barrier function.