Splenectomy attenuates obesity and decreases insulin hypersecretion in hypothalamic obese rats

Metabolism. 2015 Sep;64(9):1122-33. doi: 10.1016/j.metabol.2015.05.003. Epub 2015 May 7.

Abstract

Objective: Obesity-induced abnormalities, such as insulin resistance, dyslipidemia and hypertension, are frequently correlated with low-grade inflammation, a process that may depend on normal spleen function. This study investigated the role of the spleen in the obesity induced by monosodium glutamate (MSG) treatment.

Materials/methods: MSG-obese and lean control (CON) rats were subjected to splenectomy (SPL) or non-operated (NO).

Results: MSG-NO rats presented a high adipose tissue content, insulin resistance, dyslipidemia and islet hypersecretion, accompanied by hypertrophy of both pancreatic islets and adipocytes when compared with CON-NO rats. In addition, changes in nitric oxide response were found in islets from the MSG-NO group without associated alterations in inducible nitric oxide synthase (iNOS) or IL1β expression. MSG-NO also presented increased leukocyte counts and augmented LPS-induced nitric oxide production in macrophages. Splenectomy of MSG-obese animals decreased insulin hypersecretion, normalized the nitric oxide response in the pancreatic islets, improved insulin sensitivity and reduced hypertrophy of both adipocytes and islets, when compared with MSG-NO rats.

Conclusion: Results show that splenectomy attenuates the progression of the obesity modulating pancreas functions in MSG-obese rats.

Keywords: Insulin; Islets; Obesity; Spleen.

MeSH terms

  • Adiposity
  • Animals
  • Dyslipidemias / blood
  • Dyslipidemias / surgery
  • Hypothalamic Diseases / complications
  • Hypothalamic Diseases / metabolism
  • Hypothalamic Diseases / surgery*
  • Insulin / metabolism*
  • Insulin Resistance
  • Islets of Langerhans / metabolism
  • Male
  • Nitric Oxide / metabolism
  • Obesity / etiology
  • Obesity / metabolism
  • Obesity / surgery*
  • Rats
  • Rats, Wistar
  • Sodium Glutamate
  • Splenectomy*

Substances

  • Insulin
  • Nitric Oxide
  • Sodium Glutamate