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Morphology and morphometry of the phrenic nerve in chronic diabetic rats: an ultrastructural study

Grant number: 07/08498-7
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): April 01, 2008
Effective date (End): December 31, 2008
Field of knowledge:Biological Sciences - Morphology - Anatomy
Principal Investigator:Valéria Paula Sassoli Fazan
Grantee:Caroline Echavarria Rodrigues Jordão
Home Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil


Diabetic neuropathy is one of the most common complications of the human diabetes. Alterations on peripheral nerves are described as loss of fibers axonal degeneration and segmental demyelination. In experimental models of diabetes, morphological and functional evidences of peripheral neuropathies are described in the literature. Nevertheless, different from the human neuropathy, experimental neuropathy associated to diabetes is being described as an axonal neuropathy, being the myelin injury a consequence of the axonal damage. Among the peripheral neuropathies, the phrenic nerve diabetic neuropathy is being widely investigated Previous results from our laboratory showed that the phrenic nerves myelinated fibers of chronic streptozotocin-induced diabetic rats present morphologic and morphometric signs of axonal atrophy. However, it is widely known that the diabetic neuropathy, either in humans or in experimental animals, might be present as a small fiber neuropathy, leading to a loss of small diameter fibers. The phrenic nerve is the most important nerve involved in respiration, being the only motor supply for the diaphragm. Despite that the phrenic nerve contains a large number of myelinated fibers of large diameters (well known to be injured by chronic experimental diabetes, as previously demonstrated in our laboratory), it also contains myelinated fibers of small diameter and unmyelinated fibers, related to the autonomic nervous system, that might also be affected by diabetes. In our previous results, the investigation of the chronic experimental diabetes effects on the phrenic nerves was performed under a light microscopic approach. In this way, only the myelinated fibers were evaluated, mainly the large ones. In order o investigate the small myelinated fibers as the unmyelinated ones, a transmission electron microscopy study is necessary. The present study is designed to investigate the effects of the chronic streptozotocin-induced diabetic neuropathy in the phrenic nerves of rats, with the aid of a transmission electron microscope, aiming the morphology and morphometry of the unmyelinated fibers. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
FAZAN, VALERIA PAULA S.; RODRIGUES FILHO, OMAR A.; JORDAO, CAROLINE E. R.; MOORE, KENNETH C. Phrenic nerve diabetic neuropathy in rats: unmyelinated fibers morphometry. JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, v. 14, n. 2, p. 137-145, JUN 2009. Web of Science Citations: 12.
SASSOLI FAZAN, VALERIA PAULA; RODRIGUES FILHO, OMAR ANDRADE; RODRIGUES JORDAO, CAROLINE ECHAVARRIA; MOORE, KENNETH CHARLES. Ultrastructural Morphology and Morphometry of Phrenic Nerve in Rats. Anatomical Record-Advances in Integrative Anatomy and Evolutionary Biology, v. 292, n. 4, p. 513-517, APR 2009. Web of Science Citations: 6.

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