Biomechanical and morphometric colon remodelling in STZ‐induced diabetic rats

Abstract

Diabetes mellitus may affect the whole GI tract and cause severe symptoms. The morphometric and passive biomechanical properties were studied in the mid-colon in 6 non-diabetic and 12 streptozotocin-induced diabetic rats. The diabetic rats were divided into two equal groups living 4 weeks and 8 weeks after the induction of diabetes. The test was done as ramp distension. The diameter and length were obtained from digitised images of the segments at pre-selected pressures and at no-load and zero-stress states. Circumferential and longitudinal stresses and strains were computed from the length, diameter and pressure data and from the zero-stress state geometry. The following was found for the non-diabetic and 4 and 8 weeks diabetic groups, respectively: the blood glucose (mmol/L) (6.7±1.8, 23.6±4.4, 24.5±3.6, P< 0.001); weight (g) per cm length of the colon (0.097±0.023, 0.123±0.022, 0.144±0.031, P<0.05), wall thickness (mm) (0.39±0.08, 0.52±0.11, 0.67±0.15, P<0.05); the opening angle (degree) (118±23, 152±24, 178±34, P<0.01) and absolute values of residual strain (inner, −0.07±0.02, −0.11±0.02, −0.15±0.03; outer 0.05±0.01, 0.09±0.02, 0.13±0.03, P<0.01). Furthermore, the circumferential and longitudinal stiffness of the wall increased during diabetes (P<0.01). In conclusion, diabetic rats showed changes of morphometry and biomechanics in the colon. The study was supported by Aalborg Hospital.