Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

Autor(es)

Lubaczeuski, C. ^[1] ; Balbo, S. L. ^[1] ; Ribeiro, R. A. ^[2] ; Vettorazzi, J. F. ^[3] ; Santos-Silva, J. C. ^[3] ; Carneiro, E. M. ^[3] ; Bonfleur, M. L. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Oeste Parana, Ctr Ciencias Biol & Saude, Lab Fisiol Endocrina & Metab, Cascavel, PR - Brazil

^[2] Univ Fed Rio de Janeiro, Macae, RJ - Brazil

^[3] Univ Estadual Campinas, Inst Biol, Dept Biol Estrutural & Func, Lab Pancreas Endocrino & Metab, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 48, n. 5, p. 447-457, MAY 2015.
• Citações Web of Science: 10

Resumo

The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell morphofunctional regulation and body nutrient homeostasis in 90-day-old monosodium glutamate (MSG)-obese rats. Male newborn Wistar rats received MSG (4 g/kg body weight) or saline [control (CTL) group] during the first 5 days of life. At 30 days of age, both groups of rats were submitted to sham-surgery (CTL and MSG groups) or subdiaphragmatic vagotomy (Cvag and Mvag groups). The 90-day-old MSG rats presented obesity, hyperinsulinemia, insulin resistance, and hypertriglyceridemia. Their pancreatic islets hypersecreted insulin in response to glucose but did not increase insulin release upon carbachol (Cch) stimulus, despite a higher intracellular Ca2+ mobilization. Furthermore, while the pancreas weight was 34% lower in MSG rats, no alteration in islet and β-cell mass was observed. However, in the MSG pancreas, increases of 51% and 55% were observed in the total islet and β-cell area/pancreas section, respectively. Also, the β-cell number per β-cell area was 19% higher in MSG rat pancreas than in CTL pancreas. Vagotomy prevented obesity, reducing 25% of body fat stores and ameliorated glucose homeostasis in Mvag rats. Mvag islets demonstrated partially reduced insulin secretion in response to 11.1 mM glucose and presented normalization of Cch-induced Ca2+ mobilization and insulin release. All morphometric parameters were similar among Mvag and CTL rat pancreases. Therefore, the higher insulin release in MSG rats was associated with greater β-cell/islet numbers and not due to hypertrophy. Vagotomy improved whole body nutrient homeostasis and endocrine pancreatic morphofunction in Mvag rats. (AU)

• Processo FAPESP: 11/09012-6 - Mecanismos moleculares envolvidos na disfunção e morte de células beta pancreáticas no Diabetes Mellitus: estratégias para a inibição desses processos e para a recuperação da massa insular em diferentes modelos celulares e animais
• Beneficiário: Antonio Carlos Boschiero
• Modalidade de apoio: Auxílio à Pesquisa - Temático