[Experimental diabetic neuropathy. Morphometric studies on the rat N. suralis in short-term streptozotocin-induced diabetes].

Morphometric studies of sural nerves were performed in diabetic rats 35 or 44 d, respectively, after the administration of 60 mg/kg b.w. streptozotocin. Morphometry of photographed semithin sections was performed after whole-body glutaraldehyde perfusion both with the semiautomatic MOP Videoplan and the MOP AM 02 (Kontron, Munich, F.R.G.). The following parameters were registered: Area of nerves and fibers, perimeter of fibers, diameter of axons, thickness of myelin sheaths, form factor. No decrease of the total nerve area or of the myelinated area were found. Parameters area of fibers, thickness of myelin sheath and form factor decreased in diabetic animals. Axon diameter, ratio axon diameter-myelin sheath thickness and perimeter of fibers increased in the diabetic nerves. It is suggested that primary Schwann cell lesion is responsible for the observed myelin reduction.