Fig. 1

Analysis of gene expression and hypertrophy in the atria of WT and Nrf2^−/− mice upon HIES. a After 4-weeks of high intensity endurance exercise (HIES), atria were isolated from SED and HIES (n = 4–6/group) mice. Transcript (mRNA) levels of hypertrophy markers (Anf, Bnf, α-Mhc and β-Mhc) by qRT-PCR was analyzed and relative gene expression was calculated using Gapdh as a house-keeping gene. b Immunofluorescence images showing atrial hypertrophy in HIES WT and Nrf2^−/−. Cryo-sections from atrial tissues were fixed and stained with wheat germ agglutinin (WGA) and imaged using confocal microscopy (60 × oil immersion). c WGA staining showing the borders of atrial cardiomyocytes with cell membrane in green and DAPI stains nucleus in blue-enlarged (hypertrophy) cardiomyocytes are highlighted. d Cell size was quantified by measuring area using ImageJ software (n = 30–45 cells/group). Data is presented in the histograms (mean ± SEM). *P < 0.05 vs SED WT; ^#P < 0.05 vs SED Nrf2^−/− and ^$P < 0.05 vs HIES WT