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.
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-obeserats.
Authors: Alexandra R Himel; Erin B Taylor; Charles L Phillips; Bradley A Welch; Redin A Spann; Sibali Bandyopadhyay; Bernadette E Grayson Journal: Exp Biol Med (Maywood) Date: 2019-06-18