抄録
【Purpose】The purpose of our study was to confirm whether a low-temperature sauna（LTS）, which raises rectal temperature by approximately 2°C, would inhibit renal apoptosis in a 5/6 nephrectomy（Nx）mouse model.【Methods】Nx mice were exposed to once-daily LTS for 4 weeks. Sham operation mice were used as controls（SC）and Nx mice exposed to LTS（NS）were compared with non-LTS Nx mice（NC）. Serum creatinine（Cr）and urine albumin（u-Alb）levels were evaluated as indicators of renal disorder. HSP70 and phosphorylated HSP27（p-HSP27）and cleaved caspase 3 were evaluated by western blotting. Renal tissue samples were evaluated by pathologists blinded to the treatments. Statistical analysis was performed using Welch's t test or Dunnett's test. P values＜0.05 were considered statistically significant.【Results】At the experimental endpoint, 24-h u-Alb excretion was significant lower in the NS group than in the NC group（NS：80±51 μg/mL, NC：420±289 μg/mL；P＜0.05）. Cr level was approximately the same in the NS and NC groups. There were no significant differences in general parameters. Systolic blood pressure（SBP）was significantly lower in the NS group relative to the NC group（P＜0.05）. In a subanalysis after the adjustment for SBP, Cr and 24-h u-Alb levels were significantly lower in NS than in NC（P＜0.05）. HSP70 and p-HSP27 expression were significantly increased in NS compared with NC（P＜0.05）. In contrast, caspase 3 cleavage was significantly inhibited in the NS group compared with that in the NC group（P＜0.05）. Proximal tubule changes were observed in NC.【Discussion】LTS might exert protective effects in the Nx mouse. A potential protective effect mechanism is likely related to apoptotic inhibition via the upregulation of HSP70 and p-HSP27 in the kidney.
