2015 Volume 78 Issue 2 Pages 118-129
Objective: Sauna bathing is a popular recreational activity and has long since been used to relieve stiff necks and low back pain. Recently, low-temperature sauna has been used to treat congestive heart failure (CHF), coronary artery diseases, chronic fatigue syndrome, and chronic pain. During 1960-1970, thermal stimulation was applied to the patients with renal failure. We could not find the subsequent reports, and the long-term effects are unclear. The purpose of this experiment was to verify the safety of systemic low-temperature sauna treatment (ST) for the 5/6 remnant kidney mouse and to examine the effect of ST on urinary protein excretion.
Materials and Methods: The C57BL/6 mice were divided into the following 4 groups; group 1: sham-operated and non-sauna treatment mice (sham+non-ST group: n = 5), group 2: sham-operated and ST mice (sham+ST group: n = 5), group 3: Nx and non-ST mice (Nx+non-ST group: n = 5), and group 4: Nx and ST mice (Nx+ST group: n = 5). Mice received ST at 41°Cfor 15 min and at 32°Cfor 20 min for 12 weeks using a natural convection dry sauna system.
Results: After 12 weeks of ST, no differences were observed in creatinine clearance, body weight, fluid intake, urine volume, serum sodium and potassium levels between ST and non-ST groups. Our results showed a significant increase in eNOS mRNA expression in the Nx+ST group compared to that in the Nx+non-ST group. These results suggest the possibility that mild sauna treatment induces thermal vasodilation effects on glomerulus. Systolic blood pressure and urine protein levels in the Nx groups did not change throughout the intervention.
Conclusion: There are no clear adverse events associated with low-temperature sauna. Therefore, this study setting is safe in the CKD model mouse. Renal eNOS mRNA expression was increased by the low-temperature sauna. The present results suggest the possibility that ST might provide a renal protective effect by suppressing glomerular hypertension via stimulation of renal NO production in the CKD model mouse.