The effect of non-enzymatic glycation of extracellular matrix proteins on axonal regeneration in vitro.

Non-enzymatic glycation of peripheral nerve extracellular matrix (ECM) may contribute to the development of diabetic distal sensory neuropathy (DNP). We investigated the relative importance of glycation of collagen types I and IV, laminin and fibronectin in DNP-related impairment in peripheral nerve regeneration. Dorsal root ganglia (DRGs) from young adult mice were embedded in collagen type I modified by 10% substitution with normal or glycated forms of the proteins and incubated for 3 days. Outgrowth of axons and migration of cells into the ECM were quantified. Mean length of growing axons was significantly reduced by glycation of laminin and collagen type IV. The sum of lengths of all axons from each DRG was greatly reduced with glycated laminin, collagen types IV and I. Glycation of fibronectin had no effect on axonal growth. The number of migrating cells was not affected by glycation. We conclude that non-enzymatic glycation of laminin and collagen types IV and I (in decreasing order) impairs peripheral nerve regeneration in vitro.