慢性间歇性缺氧对大鼠胸骨舌骨肌收缩能力及疲劳指数的影响

目的 探讨慢性间歇性缺氧对大鼠上气道扩张肌即胸骨舌骨肌收缩性能的影响。方法 取健康雄性SD大鼠12只，随机分为正常对照组和慢性间歇性缺氧组，采用电刺激法，测定等长收缩胸骨舌骨肌肌条在不同条件下收缩性能及疲劳指数的变化。结果 慢性间歇性缺氧可造成大鼠胸骨舌骨肌在10和20Hz刺激下肌张力明显较对照组下降，两者比较差异有显著性；其肌肉的颤搐和强直性张力、颤搐／强直性张力比虽有所下降，但差异无显著性；此外，慢性间歇缺氧能显著增加胸骨舌骨肌的疲劳度。结论 慢性间歇性缺氧能够降低上气道扩张肌的张力，增加上气道肌的疲劳，使上气道抗疲劳能力下降，从而使其在抵抗上气道在吸气时负压的作用下降，可能参与了睡眠呼吸暂停的发病过程，加重或诱发呼吸暂停。

Effects of chronic intermittent hypoxia on rat sternohyoid contractile properties

Objective To investigate the effect of chronic intermittent hypoxia(CIH) on rat sternohyoid contractile properties.Methods 12 healthy male S-D rats were randomly assigned to two equal groups,control group and CIH group.Isometric contractile properties were determined by electrostimulating the strips of isolated sternohyoid muscles to observe the changes of the sternohyoid contractile properties in different Conditions.Results CIH had no significant effect on twitch or tetanic tension,twitch/tetanic tension ratio.However,CIH decrease sternohyoid muscle tension on the frequency of 10- and 20-Hz,and significantly increase sternohyoid fatigue.Conclusions CIH increases upper airway(UA) muscle fatigue,an effect that may compromise the maintenance of UA patency.