Influence of Creatine Supplementation and High Intensity Interval Training on Glycemic Profile and Cardiac Morphology in Rats

Abstract

BackgroundCreatine supplementation may induce insulin resistance, a condition associated with cardiac remodeling and also a risk factor for cardiovascular disease. High intensity interval training (HITT) improves glucose tolerance and promotes cardiac changes. This study evaluated the influence of creatine supplementation and HITT on glycemic profile and cardiac morphology in rats.MethodsMale Wistar rats (n=60) were allocated into four groups: sedentary control (C), control + creatine supplementation (Cr), control + physical exercise (Ex), and creatine supplementation + physical exercise (ECr). C and Ex groups were treated with standard commercial chow; Cr and ECr received the same chow supplemented with creatine 2%. Rats from Ex and ECr groups underwent into a treadmill‐HIIT protocol, 5 times per week, for 12 weeks. At the end of the experiment, glycemic profile was analyzed by glucose and insulin tolerance tests (GTT and ITT, respectively), and functional capacity was assessed by maximal exercise test on treadmill. Cardiomyocyte cross‐sectional area and myocardial collagen interstitial fraction were evaluated in left ventricle histological sections stained with hematoxylin‐eosin and Picrosirius red, respectively. Statistics: two‐way ANOVA and Tukey.ResultsFunctional capacity was improved in exercised groups compared to respective controls. Considering glycemic response in GTT, the area under curve (AUC) was lower in Ex and ECr than in C and Cr. In ITT, AUC was lower in Ex than C and ECr. Atria weight and atria weight‐to‐body weight ratio were higher in ECr than Ex and atria weight‐to‐body weight ratio was higher in Cr than C. Heart weight‐to‐body weight ratio was higher in ECr than Cr and Ex. Left and right ventricle weight was similar between the groups. Myocyte cross‐sectional area (C 227±26, Cr 216±22, Ex 284±27, ECr 297±7 μm2) and left ventricle collagen interstitial fraction (C 1.96±1.79, Cr 1.98±1.28, Ex 2.36±2.00, ECr 2.49±1.80 %) were higher in Ex and ECr than C and Cr.ConclusionHIIT improves glucose and insulin tolerance. Creatine supplementation impairs insulin tolerance in exercised rats. HIIT promotes cardiomyocyte hypertrophy and increases myocardial collagen interstitial fraction without significant influence of creatine supplementation.Support or Funding InformationCAPESThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.