title: Biomechanical and histomorphometric colon remodelling in STZ-induced diabetic rats.
abstract: The histomorphologic and passive biomechanical properties were studied in the mid-colon of 16 non-diabetic and 20 streptozotocin (STZ)-induced diabetic rats (50 mg/kg STZ, ip). The diabetic rats were divided into groups living 4 and 8 weeks after the induction of diabetes (n = 10 for each group). The mechanical test was a ramp distension of fluid into the colon in vitro. The colon diameter and length were obtained from digitized images of the segments at pre-selected pressures and at the 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 blood glucose level increased 3-4-fold in the diabetic rats compared with the controls (P < 0.001). Diabetes generated pronounced increases in the colon weight per length, wall thickness, and wall cross-sectional area (P < 0.001). Histologically, the thickness of all layers was increased during diabetes (P < 0.05), especially the mucosa layer. The opening angle, and absolute values of residual strain increased in the diabetic group (P < 0.05 and P < 0.01, respectively). Furthermore, diabetes increased the circumferential and longitudinal stiffness of the colon wall (P < 0.001). The observed changes in residual strain, opening angle, and stress-strain relation may be contributing factors to colonic dysfunction and abdominal pain in diabetic patients.
authors.affiliation: Mech-Sense, Aalborg Hospital Science and Innovation Center (AHSIC), Sdr. Skovvej 15, 9000, Aalborg, Denmark. jzhao@miba.auc.dk
authors.forename: Jingbo
authors.initials: J
authors.lastname: Zhao
authors.forename: Toshiya
authors.initials: T
authors.lastname: Nakaguchi
authors.forename: Hans
authors.initials: H
authors.lastname: Gregersen
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology; D001786:Blood Glucose / Q000378:metabolism; D003106:Colon / Q000473:pathology* / Q000503:physiopathology*; D003921:Diabetes Mellitus, Experimental / Q000473:pathology* / Q000503:physiopathology*; D004195:Disease Models, Animal; D005769:Gastrointestinal Motility / Q000502:physiology; D008954:Models, Biological; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D013311:Streptozocin