Obesity, caused by the hypertrophy of adipocytes, not only raises cosmetic issues but induces a variety of lifestyle-related diseases. Exercise can reduce body weight, but is difficult to continue daily basis. Hot bathing, relatively easy to take regularly, is also suggested improving obesity. In this study, the direct effect of hyperthermia on adipocytes using a heat shock model of mouse preadipocyte, 3T3-L1.
When heat shock at 42 °C for 1 hour was applied on 3T3-L1, expression of heat shock protein 70, the
indicator of cellular stress, was increased 30 minutes after heat shock indicating that the cells were loaded with heat stress. Heat shock at 42 °C for 1 hour also increased mitochondrial electron transport activity, which produces cellular energy from lipid, shortly after heat shock. However, the augmentation of mitochondrial function disappeared after 48 hours. High energy transporter, ATP, once decreased soon after heat shock, began to increase after 6 hours. As the heat shock increased energy production in mitochondria of 3T3-L1, I quantitated the amount of fat accumulation in adipocytes using a triglyceride assay kit. A single application of heat shock at 42 °C for 1 hour did not decrease triglyceride content in 3T3-L1 up to 96 hours after the stress.
However, when heat shock was applied every 24 hours, triglyceride decreased significantly after 4 cumulative heat shocks.
These results indicate that heat shock decreases lipid accumulation in adipocytes through the activation of energy metabolism of mitochondria. Therefore, hot bathing can prevent obesity by improving the phenotypes of fat cells.
温熱負荷が脂肪細胞のエネルギー代謝、中性脂肪蓄積におよぼす影響
202106_186-05
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