The regeneration of injured muscles is facilitated by intermittent heat stress. The 72-kDa heat shock protein (HSP72), the level of which is increased by heat stress, is likely involved in this effect, but the precise mechanism remains unclear. This study was conducted to investigate the localization and role(s) of HSP72 in the regenerating muscles in heat-stressed rats using immunohistochemistry. Heat stress was applied by immersion of the rat lower body into hot water (42C, 30 min, every other day) following injection of bupivacaine into the soleus muscles. After 1 week, we found that HSP72 was expressed at high levels not only in the surviving myofibers but also in the blood vessels of the regenerating muscles in heated rats. In addition, leukocytes, possibly granulocytes, expressing cluster of differentiation 43 within the blood capillaries surrounding the regenerating myofibers also highly expressed HSP72. In contrast, marked expression of HSP72 was not observed in the intact or regenerating muscles without heat stress. These results suggest that heat-stress-induced HSP72 within the myofibers, blood vessels, and circulating leukocytes may play important roles in enhancing regeneration of injured muscles by heat stress. Our findings would be useful to investigate cell-specific role(s) of HSP72 during skeletal muscle regeneration.

间歇性热应激促进了受伤肌肉的再生。这种作用可能与72 kDa的热激蛋白（HSP72）有关，该蛋白的水平因热应激而增加，但确切的机制尚不清楚。进行了这项研究，以利用免疫组织化学研究热应激大鼠再生肌肉中HSP72的定位和作用。在将布比卡因注射入比目鱼肌后，将大鼠下半部浸入热水中（每隔一天42℃，30分钟），施加热应激。1周后，我们发现HSP72不仅在存活的肌纤维中高表达，而且在受热大鼠中的再生肌肉血管中也高表达。另外，白细胞，可能是粒细胞 在再生肌纤维周围的毛细血管内表达分化簇43的组织也高度表达了HSP72。相反，在没有热应激的完整或再生肌肉中未观察到HSP72的明显表达。这些结果表明，肌纤维，血管和循环白细胞内热应激诱导的HSP72可能在通过热应激增强受伤的肌肉再生中起重要作用。我们的发现将有助于研究HSP72在骨骼肌再生过程中的细胞特异性作用。循环白细胞在增强热应激损伤肌肉的再生中可能起重要作用。我们的发现将有助于研究HSP72在骨骼肌再生过程中的细胞特异性作用。循环白细胞在增强热应激损伤肌肉的再生中可能起重要作用。我们的发现将有助于研究HSP72在骨骼肌再生过程中的细胞特异性作用。