Middle term intestinal adaptation after massive distal small bowel resection in oral feeding dogs

Intestinal adaptation (IA) consists mainly in a increase of the normal cell proliferative rate in the crypts of the intestinal mucosa. Histidine- and ornithine-decarboxylase (HDC and ODC, respectively) are always involved in the rapid growing tissue process. The present experiment studies the relation of HDC and ODC, the morpho-functional changes of the jejunal mucosa remnant and the nutritive state 2, 3 and 4 weeks after performing a 75% distal small bowel resection (DMSBR) in dogs fed with a standard chow. Each animal was its own control measure in a healthy state measured before provoking the DMSBR. The results demonstrated that 14 days after DMSBR, the mucosa of the jejunal remnant showed a loose of the normal characteristics of the villi and enterocyte morphology ("mucosal microinjuries"), accompanied by an increase in the depth of the crypt and in the HDC and ODC levels, while the D-glucose and L-phenylalanine absorptive capacity did not vary compared with that of the mucosa of the same animals in a healthy state. This correspond with a statistically significant altered nutritive state parameters. However, 21 days after DMSBR, the intestinal remnant mucosa initiates a structural recovery process. It was also observed a significant increase in the HDC and ODC enzymatic levels accompanied by an increased absorptive capacity and an improvement in the nutritive state parameters. Twenty eight days after DMSBR, the findings revealed a similar trend. In conclusion, in our model, between the second and fourth week the IA process is accompanied by a progressively increased HDC and ODC activities and an improvement of the nutritive state. The significance of the "mucosal microinjuries" described needs further investigation.