Effects of chronic administration of the symbiotic combination of FOS and L. fermentum in the experimental model of obese Zucker rat.

B Rivero, O Martínez-Augustin, FS de Medina, A Zarzuelo, M Galisteo. University of Granada, Pharmacology, 18071, Spain

Introduction and aims: Metabolic Syndrome is a condition in which several specific abnormalities are clustered together with insulin resistance as the primary defect, and which includes abdominal obesity, dyslipidemia, and arterial hypertension. This syndrome is directly associated with an increased risk of developing cardiovascular diseases, the major causes of mortality in patients with type 2 diabetes. Dietary fibers have documented beneficial effects in metabolic disorder, and many of them are believed to be related to their microbial fermentation in the gut. Hence, the use of probiotics may improve their beneficial effects. The main object of this study was to analyse the effects of chronic administration of the symbiotic combination of a prebiotic, short chain fructooligosacarides (FOS), and a probiotic, Lactobacillus fermentum, on many of the alterations present in a well-known experimental model of metabolic syndrome, the obese Zucker rat.

Material and methods: Male obese Zucker rats and their littermate lean Zucker rats aged 15 weeks were divided into the following groups: Lean control group (LB) (n = 10); Obese control group (OB) (n = 10); Obese rats receiving FOS (OF) (n = 10); Obese rats receiving the probiotic (OP) (n = 10); and obese rats receiving the symbiotic combination −FOS + probiotic− (OS) (n = 10). LB, OB and OP groups were fed with a standard diet. OF and OS groups received a 5 % FOS-supplemented diet. All the groups drank regular water, except for the OS that received probiotic in the drinking water. Experimental conditions were maintained for 10 weeks. Body weight was measured weekly. By the end of the experimental period, rats were sacrificed and blood was obtained to analyze biochemical parameters. Visceral adipose tissue (VAT) and liver were excised, cleaned and weighed. Plasma glucose, triglycerides, total cholesterol, and free fatty acid (FFA) concentrations were measured by colorimetric methods. Insulin and leptin concentrations in plasma, as well as TNF-alpha and adiponectin levels in VAT, were assessed using rat insulin enzyme immunoassay kits. Liver total lipids were extracted according to the Blight and Dyer method.

Results: Chronic administration of the symbiotic reduced significantly body weight and plasma levels of triglycerides, free fatty acids, total cholesterol and insulin in obese Zucker rats. The rats that received the symbiotic combination showed also a significantly lower grade of hepatomegaly compared with the OB group. Furthermore the increases in VAT, TNF-alpha and leptin concentrations observed in the OB rats were significantly reduced in the OS rats. The concentration of the adipocytokine adiponectin in VAT, dramatically decreased in the rats of the OB group, was also increased in the rats that received the symbiotic for 10 weeks.

In conclusion, our results show that dietary administration of the symbiotic combination of a diet containing 5% FOS and the probiotic L. fermentum is useful in the treatment of metabolic syndrome, as it reduced body weight, and improved dyslipidemia, hiperinsulinemia and the altered profile of VAT adipocytokines in the experimental model of metabolic syndrome of obese Zucker rats.