Objective: Damage in the capillaries supplying the MP has been proposed as a critical factor in the development of diabetic enteric neuropathy. We therefore investigated connections between STZ-induced diabetes and the BM morphology, the size of caveolar compartments, the width of TJs, the transport of albumin, and the quantitative features of Cav-1 and eNOS expression in these microvessels.
Methods: Gut segments from diabetic rats were compared with those from insulin-treated diabetics and those from controls. The effects of diabetes on the BM, the caveolar compartments, and the TJs were evaluated morphometrically. The quantitative features of the albumin transport were investigated by postembedding immunohistochemistry. The diabetes-related changes in Cav-1 and eNOS expression were assessed by postembedding immunohistochemistry and molecular method.
Results: Thickening of the BM, enlargement of the caveolar compartments, opening of the junctions, enhanced transport of albumin, and overexpression of Cav-1 and eNOS were documented in diabetic animals. Insulin replacement in certain gut segments prevented the development of these alterations.
Conclusions: These data provide morphological, functional, and molecular evidence that the endothelial cells in capillaries adjacent to the MP is a target of diabetic damage in a regional manner.
© 2012 John Wiley & Sons Ltd.