Moderate aerobic exercise training decreases middle-aged induced pathologic cardiac hypertrophy by improving Klotho expression, MAPK signaling pathway and oxidative stress status in Wistar rats

Abstract

Objective(s): This study aimed to investigate the effect of aerobic training on serum levels of Klotho, cardiac tissue levels of H2O2 and phosphorylation of ERK1/2 and P38 as well as left ventricular internal diameter (LVID), the left ventricle wall thickness (LVWT) and fibrosis in middle-aged rats. Materials and Methods: Forty wistar rats, including young rats (n= 10, 4 month-old) and middle-aged rats (n= 30, 13-15 months-old) were enrolled in this experimental study. The all young and 10 middle-aged rats were sacrificed (randomly) under deep anesthesia without any exercise training as normal young control and normal middle-aged control respectively. The remaining 20 middle-aged rats participated in 4 (n= 10) or 8-week (n= 10) aerobic exercise training. Results: There were significant differences in the plasmatic Klotho levels and the heart tissue levels of phosphorylated-ERK1/2 (p-ERK1/2), P-P38 and H2O2, LVWT, LVID and fibrosis between young and middle-aged rats (P = 0.01). Plasmatic Klotho level was significantly increased after eight weeks training (P = 0.011). Also, p-ERK1/2 was significantly decreased after eight weeks and p-P38 was significantly decreased in the fourth (P = 0.01) and eight weeks of training (P = 0.01). A similar decrease was reported for aging-induced H2O2 in the fourth (P = 0.016) and eighth weeks (P= 0.001). LVID was significantly increased in eight weeks, but LVWT and fibrosis was significantly reduced in the eighth week (P = 0.011, P = 0.028, P = 0.001 respectively). Conclusion: Moderate aerobic training attenuates aging-induced pathological cardiac hypertrophy at least partially by restoring the Klotho levels, attenuating oxidative stress, and reduction in the phosphorylation of ERK1/2, P38 and fibrosis.