Long-term administration of cola drink can lead to development of metabolic syndrome in Wistar rats

K Galkova, E Malikova, E Kralova, P Vavrinec, T Cavojsky, M Rupp, I Pavlikova, P Krenek, J Klimas. Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic, Slovakia

OBJECTIVE: As caffeine further increases sugar-sweetened beverage consumption, use of caffeine-containing beverages (cola type beverages) could be associated with a higher risk of development of metabolic syndrome than consumption of other sugar-sweetened beverages1. Our primary aim was to determine whether six months administration of cola drink can lead to the development of metabolic syndrome features in healthy rats.

DESIGN/METHODS: Male Wistar rats received a standard diet. Additionally, a group of rats received a commercially available carbon dioxide-free cola drink (CC, n=12). Controls (CON, n=7) drank drinking water. We measured weight gain, plasma triglycerides (TG) and cholesterol (CHOL) levels in capillary blood. Blood glucose was determined by conventional oral glucose tolerance test (oGTT). In addition, heart rate (HR), systolic and diastolic blood pressures (sBP and dBP) were measured by using tail-cuff method. Protein expression was determined by Western blotting in left ventricles.

RESULTS: We observed a significantly increased body weight in CC rats (541±12 g; P<0.01) when compared to controls (443±23 g). This was in accordance with a significantly increased sBP (CC: 135±3 mmHg vs. CON: 120±4 mmHg; P<0.01) and unaltered dBP (CC: 86±1 mmHg vs. CON: 85±1 mmHg; NS) and significantly increased HR (CC: 383±9 mmHg vs. CON: 312±15 mmHg; P<0.01). Postprandial glycaemia was significantly changed after 60 minutes of oGTT (CC: 9.3±0.5 mmol/L vs. CON: 6.6±0.6 mmol/L; P<0.01) and after 90 minutes of follow up (CC: 8.3±0.4 mmol/L vs. CON: 6.6±0.5 mmol/L; P<0.01). Additionally, we observed a non-significant tendency of increased TG (CC: 5.2±0.4 mmol/L vs. 5±0.5 mmol/L; NS). In addition, we found a significant increase in the expression of endothelial NO synthase (eNOS) (CC: 142±26 % vs. CON: 100±26 %; P<0.01) in the left ventricle, but the protein expressions of its modulators heat shock protein 90 (hsp90) and caveolin 1 (cav-1) were significantly unchanged.

CONCLUSION: Prolonged administration of cola drink can lead to the development of cardiovascular (increased BP,HR,eNOS) as well as metabolic manifestations (impaired glucose tolerance) in Wistar rat and so mimics clinical features of human metabolic syndrome. Consequently, we propose this model as a reliable experimental model of rat metabolic syndrome for further use in pharmacological research.

References: 1., Keast RS, Swinburn BA, Sayompark D, et al. (2014) Caffeine increases sugar-sweetened beverage consumption in a free-living. In Br J Nutr. 2015 Jan 8:1-6. Grant support: APVV-0887-11, VEGA1/0564/13