Shima Yosuke, Kitaoka Katsuhiko, Yoshiki Yumiko, Maruhashi Yoshinobu, Tsuyama Takeshi, Tomita Katsuro
Department of Orthopedic Surgery, Kanazawa University, Kanazawa, Japan.
J Physiol Sci. 2008 Oct;58(5):341-8. doi: 10.2170/physiolsci.RP004808. Epub 2008 Oct 7.
The mechanisms of the protective effect conferred by heat shock preconditioning (HS) are currently unknown. The purpose of this study was to determine the effect of HS on muscle injury after downhill running and to address the mechanism of the effect. Female Wistar rats were assigned to three groups: HS, downhill running (E), and downhill running after heat shock preconditioning (HS + E). The HS and HS + E rats were placed in a heat chamber for 60 min (ambient temperature 42 +/- 1.0 degrees C) 48 h before downhill running. Reactive oxygen species (ROS) scavenging activity was determined by electron spin resonance (ESR), and heat shock protein 72 (HSP72) mRNA expression was measured in rat quadriceps femoris. Leukocyte infiltration and degenerated muscle fibers were determined histopathologically. ROS scavenging activity significantly increased at 3 days after HS (151 +/- 18%) and HSP72 mRNA expression increased immediately after HS (1750 +/- 1914%). No decrease in ROS scavenging activity was observed in the HS + E rats at 2 days after exercise compared with the E rats (102 +/- 9% vs. 79 +/- 5%). Degenerated muscle fibers in HS + E rats were significantly less than in E rats at 2, 3, and 7 days after exercise (0.8 +/- 1.0 vs. 2.8 +/- 1.6, 0.8 +/- 1.0 vs. 1.8 +/- 1.6, 0 vs. 0.3 +/- 0.6, respectively). These data demonstrated that HS can reduce muscle injury after downhill running, and this effect may be mediated by increased ROS scavenging activity. Furthermore, HS may protect the antioxidant defense system in skeletal muscle by enhancing the adaptive HSP72 mRNA response.
热休克预处理（HS）所赋予的保护作用机制目前尚不清楚。本研究的目的是确定HS对下坡跑后肌肉损伤的影响，并探讨其作用机制。将雌性Wistar大鼠分为三组：HS组、下坡跑组（E组）和热休克预处理后下坡跑组（HS + E组）。HS组和HS + E组大鼠在进行下坡跑前48小时置于热室中60分钟（环境温度42±1.0℃）。通过电子自旋共振（ESR）测定活性氧（ROS）清除活性，并在大鼠股四头肌中测量热休克蛋白72（HSP72）mRNA表达。通过组织病理学方法确定白细胞浸润和变性肌纤维。HS后3天ROS清除活性显著增加（151±18%），HS后HSP72 mRNA表达立即增加（1750±1914%）。与E组相比，HS + E组大鼠运动后2天ROS清除活性没有降低（102±9%对79±5%）。运动后2天、3天和7天，HS + E组大鼠的变性肌纤维明显少于E组（分别为0.8±1.0对2.8±1.6、0.8±1.0对1.8±1.6、0对0.3±0.6）。这些数据表明，HS可以减轻下坡跑后的肌肉损伤，这种作用可能是通过增加ROS清除活性介导的。此外，HS可能通过增强适应性HSP72 mRNA反应来保护骨骼肌中的抗氧化防御系统。
