LAUSR

Corneal confocal microscopy (CCM) has been used to evaluate small nerve fibers in the cornea [1]. CCM studies also have revealed that the density of nerve fibers in the subbasal nerve plexus (SBNP) correlates with the severity of diabetic sensory neuropathy in human patients, suggesting that such analyses represent an alternative, noninvasive marker of peripheral neuropathy in patients with diabetes. As for animal models, some researchers have investigated the severity of diabetic peripheral neuropathy by evaluating the corneal nerves within the SBNP in mouse and rat models of diabetes [2]. However, such studies have showed contradictory results, with some demonstrating significant decreases in fiber density and others reporting no abnormalities. Recently, we have elucidated that extended duration of hyperglycemia result in human-like corneal nerve lesions in mice with alloxanand streptozotocin-induced type 1 diabetes [3]. WBN/Kob rats spontaneously develop long-lasting diabetes and human-like diabetic peripheral motor neuropathy characterized by segmental demyelination and axonal atrophy, with slowing of the nerve conduction velocity [4, 5]. However, morphological change of the sensory nerve terminal remains to be elucidated in this strain. In the present study, we investigated whether the density of corneal nerve fiber can be useful as an alternative morphological marker of diabetic peripheral neuropathy in diabetic WBN/Kob rats.