HYPOGLYCEMIC NEUROPATHY IN BB WOR RATS TREATED WITH INSULIN IMPLANTS - ELECTRON-MICROSCOPIC OBSERVATIONS/

Insulin-dependent diabetes mellitus is a chronic metabolic disease tha t causes long-term secondary complications such as neuropathy. The occ urrence of diabetic neuropathy has generally been thought of as being associated with hyperglycaemia. However, in a previous light microscop ic examination of plantar nerves in diabetic BB/Wor rats treated with insulin implants we found that eu-/hyperglycaemic rats present a norma l picture, whereas eu-/hypoglycaemic rats show severe changes. The aim of the present work is to supplement our previous light microscopic r eport with electron microsocpic data from the lateral plantar nerve of normal, eu-/hyperglycaemic and eu-/hypoglycaemic BB/Wor rats. Under t he electron microscope lateral plantar nerves collected from eu-/hyper glycaemic rats presented a qualitatively normal picture. In addition, the fibre numbers and the size distribution of the myelinated fibres w ere normal. In contrast, specimens from eu/hypoglycaemic BB/Wor rats s howed severe qualitative changes, interpreted as signs of axonal de- a nd regeneration. The total number of axons was somewhat subnormal and the sizes of the myelinated fibres were strongly shifted towards small er diameters. These data confirm our previous light microscopic observ ations. We conclude that eu-/hypoglycaemic BB/Wor rats treated with in sulin implants, but not similarly treated eu-/hyperglycaemic animals, develop a neuropathy in their plantar nerves.