Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCB206

Poster Communications

Vagal afferents modulate high fat diet induced visceral obesity and dysbiosis

B. A. Çevlikli2, C. Tanman2, E. Yircali2, A. Ürpekli2, F. C. yildiz2, Z. N. Özdemir Kumral1, S. Arabaci Tamer1, L. Sen1, K. Ozguler3, B. Aksu3, B. Yegen1, N. Imeryüz1,4

1. Faculty of Medicine, Department of Physiology, Marmara University, Istanbul, Turkey. 2. Faculty of Medicine, Marmara University, Istanbul, Turkey. 3. Faculty of Medicine, Department of Microbiology, Marmara University, Istanbul, Turkey. 4. Faculty of Medicine, Department of Gastroenterology, Marmara University, Istanbul, Turkey.

Obesity has been characterized by an abnormal microbiota composition or dysbiosis (1). Chronic consumption of high fat diet promotes dysbiosis before any changes in body weight in rats (2). Diet-driven microbiota dysbiosis is associated with decreased vagal outputs to the central nervous system (3). The aim was to determinate to the interaction the gut microbiota and the vagal afferents on sulphate-producing Desulphovibrio piger (D. piger). Sprague-Dawley rats (male, 10 weeks old) were randomly divided as control (n=5), vagal denervation (Vx) (n=10), sham operated Vx (n=13) groups. Vx was induced perivagal 1% capsaicin administration, vehicle (10% Tween 80 in oil) was applied to make sham Vx. After 3 weeks of recovery, we have performed blink reflex to elucidate succession of the Vx. The rats were fed with chow diet (fat 2-7%) for the first 4 weeks and fed the high fat diet (HFD, % 45 fat) for the last 4 weeks until decapitation. Food intake was monitored daily and body weight was measured weekly. Food and water intake were measured after 16 hrs. of food and 24 hrs. of water deprivation in the last week. Weight of faeces for 16 hrs. and small intestinal transit (SIT) time with charcoal were measured. Fecal samples were taken at 0-3-7th weeks under sterile conditions to detect D. piger by qPCR. At the end of the 8 weeks, rats were decapitated and epididymal fat and liver was weighted and calculated as gr/ 100gr body weight . Data was expressed as S.E.M, comparison between groups were done with ANOVA. The blink number was decreased in Vx group as compared to control group (Vx:9.6±1.3, control: 12.6±2.4, p<0.01). Weight gain was similar during normal feeding, final weight gain was also comparable among study groups. The epididymal fat weight was significantly decreased in the Vx group (0.96±0.11, p<0.05) compared to sham-Vx (1.41±0.13), while liver weight and SIT time did not differ between the groups. Food consumption was higher calorically in HFD Vx group than HFD control group after 16 hrs. of food deprivation (Vx:15.7±1, control: 12.5±1, p<0.05). Water consumption after deprivation was similar in all study groups. During the normal diet or HFD period, Vx did not induce any alteration in D. piger as compared to control, but D.piger raised in HFD Vx (p<0.01) and HFD sham Vx (p<0.05) groups compared to normal diet Vx and sham Vx, respectively. Vagal afferents denervation ameliorates HFD associated visceral obesity. Vagal afferent nerves and HFD affect D. piger content of faeces. But further studies are needed to clarify interaction between vagal afferents and dysbiosis to control obesity.

Where applicable, experiments conform with Society ethical requirements