Effect of Tangweian Jianji on the Biomechanical and Morphometric Remodeling of Colon and Rectum in STZ Induced Diabetic Rats

AIM: The aim of the study was to investigate the effect of TWAJJ on the biomechanical and morphometrical remodeling of colon and rectum in streptozotocin (STZ) induced diabetic rats. METHODS: The colonic and rectal segments obtained from diabetic (DM), TWAJJ treated diabetic (TH, high dosage: 10 g/kg; TL, low dosage: 5 g/kg) and normal (CON) rats were used for the study. Blood glucose and serum insulin levels were measured. At the end of experiment, the circumferential length, the wall thickness and the opening angle were measured from the digitized images of those segments and residual strain was computed. Circumferential and longitudinal stresses and strains were computed from the length, diameter and pressure data and from the zero-stress state geometry for the colonic segment. RESULTS: The glucose and insulin levels did not differ among DM, TH and TL groups. Wet weight, wall thickness, cross-sectional wall area, opening angle, and absolute values of residual strain of colonic and rectal segments in DM group were significantly higher than those in CON group ( P <0.05 and P <0.01), whereas those parameters in TH group but not in TL group were significantly lower than those in DM group ( P <0.05, P <0.01). Furthermore, the circumferential and longitudinal stiffness of the colonic wall increased in DM group compared those with CON group. TH but not TL treatment could significantly decrease the colonic wall stiffness in both directions ( P <0.01). CONCLUSION: Although TWAJJ (high dose) treatment could not significantly correct the changes of blood glucose and serum insulin levels in the diabetic rats; it could partly restore the morphometric and biomechanical remodeling of lower GI tract caused by diabetes.