Hypoxia and hypercapnia affect contractile and histological properties of rat diaphragm and hind limb muscles.
Hypoxia and hypercapnia affect contractile and histological properties of rat diaphragm and hind limb muscles.
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DOI：
10.1016/j.pathophys.2003.09.003
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发表时间：
2004-07-01
期刊：
影响因子：
--
通讯作者：
Fukuchi, Yoshinosuke
中科院分区：
文献类型：
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作者：
Shiota, Satomi;Okada, Takao;Fukuchi, Yoshinosuke
观察低氧和高碳酸血症对大鼠后肢横隔肌和骨骼肌收缩和组织学特性的影响。8周龄雄性SD大鼠([公式：见文本])在低压低氧([公式：见文本])或高二氧化碳([公式：见文本])舱中饲养6周，并与对照组(室内空气，[公式：见文本])进行比较。用收缩动力学、力-频率曲线和疲劳耐力来评价其收缩性能。收缩活动实验结束后，固定肌肉，用ATPase染色进行组织学检查。结果表明，低氧条件下，大鼠膈肌最大收缩张力降低，但无明显的组织学改变；高二氧化碳状态下，大鼠的收缩和组织学改变明显。后肢骨骼肌在低氧和高碳酸血症条件下也会受到影响，但收缩和组织学变化的轮廓与横隔膜不同。这些结果表明，低氧和高二氧化碳对呼吸肌和后肢肌的收缩和组织学特性有不同程度的影响。此外，当我们考虑慢性阻塞性肺疾病(COPD；缺氧和高碳酸血症都有很深的影响)涉及的条件时，我们的结果表明COPD应该被视为一种全身疾病，而不是一种呼吸系统疾病。
The effects of hypoxia and hypercapnia on contractile and histological properties of the diaphragm and skeletal muscles of the hind limb were examined. Eight-week-old male Sprague-Dawley rats ( [Formula: see text] ) were kept in hypobaric hypoxic ( [Formula: see text] ) or hypercapnic ( [Formula: see text] ) chambers for 6 weeks, and compared with the control rats (room air, [Formula: see text] ). Contractile properties were evaluated with twitch kinetics, force-frequency curve and fatigue tolerance. After the experiments on contractile activities, muscles were fixed for histological examination with ATPase staining. It was demonstrated that peak twitch tension of diaphragm decreased with no significant histological changes under hypoxic conditions while significant contractile and histological changes were observed under hypercapnic conditions. Skeletal muscles of the hind limbs were affected also under hypoxic and hypercapnic conditions but the profiles of the changes in contraction and histology were different from those of the diaphragm. These results suggest that hypoxia and hypercapnia affect differently on contractile and histological properties of respiratory and hind limb muscles. Furthermore, when we consider the conditions involved in chronic obstructive respiratory disease (COPD; both hypoxia and hypercapnia are deeply involved), our results indicate that COPD should be regarded as a systemic disorder rather than a respiratory disease.