Diabetes increases mechanical sensitivity and causes morphological abnormalities in the sural nerve that are prevented by treadmill training

Abstract

In this investigation we evaluated the effects of treadmill training on mechanical sensitivity and sural nerve morphology in diabetic rats. Rats were divided into 3 groups: control (C); diabetic (D); and trained diabetic (TD). Training was performed for 8 weeks. Mechanical sensitivity was evaluated using von Frey filaments. Sural nerve analysis included fiber area, diameter, density of myelinated fibers, area occupied by connective tissue, myelin sheath thickness, and g-ratio. Animals in the D group had a reduced mechanical sensitivity threshold. Morphometric study showed that the D group had a smaller myelinated fiber area and diameter, higher density of fibers and area occupied by connective tissue, thinner myelin sheath, and higher g-ratio. The D group had a higher percentage of small myelinated fibers and a lower percentage of large-diameter myelinated fibers than the C and TD groups. Training prevents functional and morphological abnormalities in the sural nerve caused by diabetes.