Effect of different resistance-training regimens on the WNT-signaling pathway

Abstract

The purpose of the present study was to evaluate the effects of 8weeks of strength and power training on the expression of genes related to the canonical WNT pathway and β-catenin protein levels in physically active men. Twenty-five subjects (27.4±4.6years) were balanced based on their relative maximum strength in the squat exercise (squat 1RM/body mass) and randomly assigned to strength training (ST) (n=10), power training (PT) (n=10), and control (C) (n=5) groups. The ST and the PT groups performed high and low intensity squats, respectively, thrice a week, for 8weeks. Muscle biopsies from the vastus lateralis muscle were collected before and after the training period. Relative strength and power increased similarly in both ST and PT groups (P<0.001). Fiber cross-sectional area also increased similarly in both ST and PT groups. Gene expression and β-catenin protein expression levels were assessed by real-time PCR and Western blot. Certain genes were up-regulated in the ST group (WNT1: 6.4-fold, P<0.0001; SFRP1: 3.3-fold, P<0.0001 and LEF1: 7.3-fold, P<0.0001) and also in the PT group (WNT1: 24.9-fold, P<0.0001; SFRP1: 2.7-fold, P<0.0001; LEF1: 34.1-fold, P<0.0001 and Cyclin D1: 7.7-fold, P<0.001). In addition, the expression of key WNT pathway genes was substantially more responsive to PT than to ST (WNT1: P<0.0001; LEF1: P<0.0001 and Cyclin D1: P<0.001). Finally, the total β-catenin protein content increased only in the PT group (P<0.05). Our data indicate that a PT regimen triggers greater responses in key elements of the WNT pathway.