Renal nerve ultrastructural alterations in short term and long term experimental diabetes

Autor(es)

Sato, Karina Laurenti ^{[1, 2, 3]} ; Sanada, Luciana Sayuri ^{[1, 2, 3]} ; Ferreira, Renata da Silva ^{[1, 2, 3]} ; de Barros Oliveti de Marco, Maria Carolina del Bem ^{[1, 2, 3]} ; Castania, Jaci Airton ^[4] ; Salgado, Helio Cesar ^[4] ; Nessler, Randy Alan ^[1] ; Sassoli Fazan, Valeria Paula ^{[1, 2, 3, 5]}

Afiliação do(s) autor(es)

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

^[2] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Neurosci, BR-14049 Ribeirao Preto - Brazil

^[3] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Behav Sci, BR-14049 Ribeirao Preto - Brazil

^[4] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Physiol, BR-14049 Ribeirao Preto - Brazil

^[5] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Surg & Anat, BR-14049 Ribeirao Preto - Brazil

• Tipo de documento: Artigo Científico
• Fonte: BMC NEUROSCIENCE; v. 15, JAN 5 2014.
• Citações Web of Science: 4

Resumo

Background: Despite the evidence that renal hemodynamics is impaired in experimental diabetes, associated with glomeruli structural alterations, renal nerves were not yet investigated in experimental models of diabetes and the contribution of nerve alterations to the diabetic nephropathy remains to be investigated. We aimed to determine if ultrastructural morphometric parameters of the renal nerves are affected by short term and/or long term experimental diabetes and if insulin treatment reverses these alterations. Left renal nerves were evaluated 15 days or 12 weeks (N = 10 in each group) after induction of diabetes, with a single injection of streptozotocin (STZ). Control rats (N = 10 in each group) were injected with vehicle (citrate buffer). Treated animals (N = 10 in each group) received a single subcutaneous injection of insulin on a daily basis. Arterial pressure, together with the renal nerves activity, was recorded 15 days (short-term) or 12 weeks (long-term) after STZ injection. After the recordings, the renal nerves were dissected, prepared for light and transmission electron microscopy, and fascicle and fibers morphometry were carried out with computer software. Results: The major diabetic alteration on the renal nerves was a small myelinated fibers loss since their number was smaller on chronic diabetic animals, the average morphometric parameters of the myelinated fibers were larger on chronic diabetic animals and distribution histograms of fiber diameter was significantly shifted to the right on chronic diabetic animals. These alterations began early, after 15 days of diabetes induction, associated with a severe mitochondrial damage, and were not prevented by conventional insulin treatment. Conclusions: The experimental diabetes, induced by a single intravenous injection of STZ, in adult male Wistar rats, caused small fiber loss in the renal nerves, probably due to the early mitochondrial damage. Conventional treatment with insulin was able to correct the weight gain and metabolic changes in diabetic animals, without, however, correcting and / or preventing damage to the thin fibers caused by STZ-induced diabetes. The kidney innervation is impaired in this diabetic model suggesting that alterations of the renal nerves may play a role in the development of the diabetic nephropathy. (AU)

• Processo FAPESP: 10/12518-6 - Avaliação morfológica e comparação dos tipos de fibras dos músculos gastrocnêmios lateral e medial e flexor longo do hálux após estimulação dolorosa no período neonatal
• Beneficiário: Valéria Paula Sassoli Fazan
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 04/01390-8 - Avaliação morfológica das alterações do nervo renal de ratos diabéticos induzidos experimentalmente
• Beneficiário: Valéria Paula Sassoli Fazan
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 09/50389-6 - Regulação cardiocirculatória em condições fisiológicas e fisiopatológicas
• Beneficiário: Helio Cesar Salgado
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 09/16748-9 - Avaliação morfológica e morfométrica do nervo frênico de ratos espontaneamente hipertensos em diferentes fases do desenvolvimento
• Beneficiário: Valéria Paula Sassoli Fazan
• Modalidade de apoio: Auxílio à Pesquisa - Regular