Abnormal expressions of AGEs, TGF-β1, BDNF and their receptors in diabetic rat colon–Associations with colonic morphometric and biomechanical remodeling

Present study aims to investigate the role of AGEs, TGF-β1, BDNF and their receptors on diabetes-induced colon remodeling. Diabetes was induced by a single tail vein injection 40 mg/kg of STZ. The parameters of morphometric and biomechanical properties of colonic segments were obtained from diabetic and normal rats. The expressions of AGE, RAGE, TGF- β1, TGF- β1 receptor, BDNF and TrkB were immunohistochemically detected in different layers of the colon. The expressions of AGE, RAGE, TGF-β1 and TGF- β1 receptor were increased whereas BDNF and TrkB were decreased in the diabetic colon (P < 0.05, P < 0.01). AGE, RAGE and TGF-β1 receptor expressions were positively correlated whereas the BDNF expression was negatively correlated with most of the morphometry and biomechanical parameters (P < 0.05, P < 0.01, P < 0.001). AGE, TGF- β1 and BDNF in different layers correlated with their receptors RAGE, TGF- β1 receptor and TrkB respectively. STZ-induced diabetes up-regulated the expression of AGE, RAGE, TGF- β1 and TGF- β1 receptors and down-regulated BDNF and TrkB in different layers of diabetic colon mainly due to hyperglycemia. Such changes maybe important for diabetes-induced colon remodeling, however it is needed to further perform mechanistic experiments in order to study causality or approaches that explain the relevance of the molecular pathways.