BDNF and diabetes mellitus: In order to investigate whether AGE, RAGE, TGF- β1 and their receptors play a role in the colon remodeling induced by diabetes, the expressions of AGE, RAGE, TGF- β1, TGF- β1 receptor, BDNF and TrkB were detected in the colon wall of streptozotocin (STZ)-induced rats.