Effects Of Physical Exercise On The Modulation Of Aquaglyceroporin 7 From Visceral Adipose Tissue

Abstract

A role for aquaglyceroporin 7 (AQP7) in the control of lipid accumulation in white adipose tissue (WAT) has been hypothesized; however limited information is available regarding the impact of physical exercise. PURPOSE: We aimed to analyze the role of voluntary physical activity (VPA) and endurance training (ET) on WAT AQP7 expression of HFD-fed rats. METHODS: Male Sprague-Dawleys rats were assigned into sedentary (S), VPA and ET groups fed an isoenergetic Lieber-DeCarli-liquid diet: a standard diet (35% fat-derived Kcal) or a high fat-diet (HFD), (70% fat-derived Kcal), as follows: SS, SVPA, SET, HS, HVPA and HET, during 17 wks. VPA groups had free access to running wheel throughout the entire protocol. After 9 weeks of HFD, SET and HET animals were submitted to 8-wks of ET on treadmill while maintained dietary treatments. Plasma non-esterified fatty acid (NEFA), glycerol and insulin levels were determined and epididymal white adipose tissue (eWAT) was used to determine gene and protein expression of AQP7 and fatty acid translocase (FAT/CD36). Diet and exercise effects were performed using 2-way ANOVA. RESULTS: The relative caloric intake was constant between groups. HFD increased visceral adiposity index (9.0±0.2 vs. 11.8±0.4; p<0.0001) and adipocyte area mean (3716.1±301.4 vs. 5348.6±471.5; p<0.001), ET reduced these obesity-related anatomical features (p<0.001). Both AQP7 and FAT/CD36 protein and gene expression remained unchanged after HFD regimen. VPA decreased plasma glycerol levels (12.6±0.8 vs. 12.5±0.6; p<0.001) and eWAT AQP7 gene expression (p<0.001) in S diet-fed animals and had no impact neither on plasma NEFA levels nor FAT/CD36 protein content. Eight-wks of ET decreased NEFA (SS vs. SET, 16.4±0.5 vs. 12.0±0.4; HS vs. HET, 14.7±0.7 vs. 10.8±0.7, p<0.001) and glycerol (SS vs. SET, 17.4±0.7 vs. 12.5±0.6; HS vs. HET, 15.6±0.5 vs. 10.3±0.9; p<0.001) plasma levels. ET decreased gene and protein expression of AQP7 (p<0.001) in eWAT in both diet types and increased FAT/CD36 gene (p<0.001) in SET group and its protein expression (p<0.001) in both diet types. CONCLUSION: Our data suggest that 8-wks of ET decreased AQP7 expression, which might play an important role preventing lipid overaccumulation in visceral adipose tissue of obese rats. Supported by: UID/DTP/00617/2013; POCI-01-0145-FEDER-016690