Barfoot Michael K, Braun Jessica L, Wallace Phillip J, Marcella Bianca M, Baranowski Ryan W, MacPherson Rebecca E K, Cheung Stephen S, Fajardo Val A
Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.
Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada.
Physiol Rep. 2025 May;13(10):e70385. doi: 10.14814/phy2.70385.
Heat therapy (HT) has been shown to induce physiological adaptations in muscle, including a reduction in the severity of muscle atrophy resulting from unloading. The muscle atrophy caused by unloading can be partially attributed to the dysregulation of Ca in the muscle cell, which can activate calpain-mediated proteolysis. The sarco(endo)plasmic reticulum Ca-ATPase (SERCA) is a primary regulator of Ca in muscle, and SERCA dysfunction has been repeatedly demonstrated in various models of muscle unloading. Heat shock protein 70 (HSP70) is a heat-inducible chaperone protein that binds to SERCA and protects against its dysfunction. While previous research has shown HT to upregulate HSP70 in rodent muscle, even in the unloaded state, the effects of HT on SERCA function in rodent skeletal muscle under these conditions remain unknown. Here, we characterized the effects of 4 weeks of HT on soleus muscle size, HSP70 expression, SERCA function, and maximal calpain activity in male C57BL/6J mice subjected to muscle unloading through tenotomy. Four weeks of HT preserved the cross-sectional area of soleus myofibres following tenotomy, while also upregulating HSP70, maintaining SERCA-mediated Ca uptake, and reducing maximal calpain activity. Therefore, our research offers new insights into the advantages of HT for muscle health and physiology.
热疗法（HT）已被证明可诱导肌肉产生生理适应性变化，包括减轻因废用导致的肌肉萎缩严重程度。废用引起的肌肉萎缩部分可归因于肌肉细胞内钙的调节异常，这会激活钙蛋白酶介导的蛋白水解作用。肌浆（内质）网钙 - ATP酶（SERCA）是肌肉中钙的主要调节因子，在各种肌肉废用模型中反复证明存在SERCA功能障碍。热休克蛋白70（HSP70）是一种热诱导伴侣蛋白，它与SERCA结合并防止其功能障碍。虽然先前的研究表明HT可上调啮齿动物肌肉中的HSP70，即使在废用状态下也是如此，但在这些条件下HT对啮齿动物骨骼肌中SERCA功能的影响仍然未知。在这里，我们通过切断跟腱使雄性C57BL / 6J小鼠肌肉废用，研究了4周热疗法对比目鱼肌大小、HSP70表达、SERCA功能和最大钙蛋白酶活性的影响。4周的热疗法在切断跟腱后保留了比目鱼肌纤维的横截面积，同时上调了HSP70，维持了SERCA介导的钙摄取，并降低了最大钙蛋白酶活性。因此，我们的研究为热疗法对肌肉健康和生理的益处提供了新的见解。
