Effect of an Elemental Diet on the Mechanical Resistance and Morphology of the Colon in Rats

The aim of this study was to investigate the effect of an elemental diet (ED) on colonic morphology and mechanical resistance. Rats received either laboratory chow (control group; n = 6) or oral total parenteral nutrition solution (ED group; n = 6). After 14 d the colon was measured and weighed with and without the contents. Bursting pressure was determined in the right and left colon. Samples of these segments were examined histologically. Crypt depth and wall width (WW) were measured. All animals gained body weight. The bowels of ED-fed animals were shorter (23.7 ± 1.6 versus 19.7 ± 1.8 cm; P = 0.003) and weighed less than the controls either with (10.3 ± 0.8 versus 5.0 ± 0.7g, P < 0.001) or without (4.9 ± 0.9 versus 2.6 ± 0.3 g; P < 0.001) feces. Bursting pressure was lower in animals receiving ED compared with controls (right colon: 250 ± 30 versus 200 ± 30 mm Hg; P = 0.03; left colon: 195 ± 22 versus 160 ± 14 mm Hg; P = 0.009). Crypt depth and WW were significantly shorter in the left colon in the ED group. Administration of ED promotes lack of mechanical resistance and atrophy of the colonic wall, especially in the left colon.