Effects of nucleosides and a nucleotide mixture on gut mucosal barrier function on parenteral nutrition in rats

We have previously reported that the addition of nucleosides and a nucleotide mixture (OG-VI) to total parenteral nutrition (TPN) prevents TPN-induced intestinal mucosal atrophy and results in increased intestinal cathepsin activities under TPN. The aims of the present study are to examine the effects of OG-VI on mucosal barrier functions and to clarify whether the intestinal cathepsins can be used as a new marker of mucosal barrier function.

Male Wistar rats were divided into three groups: FED (food ad libitum), TPN (a standard TPN solution), and OG (OG-VI in addition to the TPN solution). Mucosal barrier functions were analyzed by the lactulose/mannitol (L/M) test, mucosal ZO-1 messenger RNA level, and electron micrographs in the gut. Intestinal cathepsin B, H, and L activities were also measured.

The L/M ratio for TPN was much higher than that for FED. Only lactulose excretion was significantly reduced by OG-VI. The intercellular spaces of the mucosal cells for TPN were significantly wider than those for FED, but were reduced in size by the addition of OG-VI. All cathepsin activities of the ileum were higher for TPN than for FED, whereas OG showed no increase.

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.