Waon therapy attenuates cardiac hypertrophy and promotes myocardial capillary growth in hypertensive rats: a comparative study with fluvastatin

Cardiac hypertrophy and fibrosis in heart failure with preserved ejection fraction are associated with a pro-inflammatory state and reduced NO bioavailability. Effects on myocardial structural and molecular alterations were compared between Waon therapy (WT; repeated dry sauna therapy) and statin in hypertensive rats. Seven-week-old Dahl salt-sensitive rats were assigned to 4 groups: low-salt (LS) diet, high-salt (HS) diet, HS diet with oral fluvastatin (FL; 10 mg/kg/day for 4 weeks) starting from the age of 9 weeks, and HS diet with WT treatment in a far-infrared dry sauna (39 °C for 15 min followed by 34 °C for 20 min once daily for 4 weeks). HS rats developed left ventricular (LV) hypertrophy with preserved LV systolic function. WT reduced LV wall thickness and myocyte cross-sectional area along with decreased levels of myocardial ANP and BNP mRNA expression compared with HS rats. Reduction in LV fibrosis and increase in capillary density in WT animals were accompanied by reductions in myocardial levels of TGF-β1, MMP2, p22^phox and gp91^phox mRNA expression, and increases in myocardial levels of VEGF and HSP90 mRNA and phosphorylated eNOS protein. These effects were comparable between WT and FL animals. WT improves structural and molecular alterations in salt-induced hypertensive rats similarly to fluvastatin.