Phrenic nerve diabetic neuropathy in rats: unmyelinated fibers morphometry

Author(s)

Fazan, Valeria Paula S. ^{[1, 2]} ; Rodrigues Filho, Omar A. ^[3] ; Jordao, Caroline E. R. ^[2] ; Moore, Kenneth C. ^[1]

Affiliation

^[1] Univ Iowa, Cent Microscopy Res Facil, Iowa City, IA - USA

^[2] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Surg & Anat, BR-14049900 Ribeirao Preto - Brazil

^[3] Univ Fed Triangulo Mineiro, Dept Biol Sci, Uberaba, MG - Brazil

• Document type: Journal article
• Source: JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM; v. 14, n. 2, p. 137-145, JUN 2009.
• Web of Science Citations: 12

Abstract

We have demonstrated that phrenic nerves' large myelinated fibers in streptozotocin (STZ)-induced diabetic rats show axonal atrophy, which is reversed by insulin treatment. However, studies on structural abnormalities of the small myelinated and the unmyelinated fibers in the STZ-model of neuropathy are limited. Also, structural changes in the endoneural vasculature are not clearly described in this model and require detailed study. We have undertaken morphometric studies of the phrenic nerve in insulin-treated and untreated STZ-diabetic rats and non-diabetic control animals over a 12-week period. The presence of neuropathy was assessed by means of transmission electron microscopy, and morphometry of the unmyelinated fibers was performed. The most striking finding was the morphological evidence of small myelinated fiber neuropathy due to the STZ injection, which was not protected or reversed by conventional insulin treatment. This neuropathy was clearly associated with severe damage of the endoneural vessels present on both STZ groups, besides the insulin treatment. The STZ-diabetes model is widely used to investigate experimental diabetic neuropathies, but few studies have performed a detailed assessment of either unmyelinated fibers or capillary morphology in this animal model. The present study adds useful information for further investigations on the ultrastructural basis of nerve function in diabetes. (AU)

• FAPESP's process: 06/06362-8 - Ultrastructural morphological evaluation of renal nerve alterations in experimentally induced diabetic rats
• Grantee: Valéria Paula Sassoli Fazan
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 07/08498-7 - Morphology and morphometry of the phrenic nerve in chronic diabetic rats: an ultrastructural study
• Grantee: Caroline Echavarria Rodrigues Jordão
• Support Opportunities: Scholarships in Brazil - Scientific Initiation