低氧大鼠脑、肺组织NO、NOS变化及其机理研究

CHANGES OF NO AND NOS AND ITS MECHANISM IN RATS DURING ACUTA AND INTERMITTENT HYPOXA

探讨低氧时一氧化氮 (NO)、一氧化氮合酶 (NOS)变化及发生变化的机理。方法 :大鼠分为常氧对照组、间断低氧习服组和急性低氧组。分别测定脑、肺NO、NOS及NOS催化反应平衡常数 (Keq)。结果 :与常氧对照比较 ,低氧大鼠 (急性低氧组 ,低氧习服组 )脑、肺NO水平明显下降 (P <0 .0 1) ;急性低氧组NOS活力明显下降 (P <0 .0 1) ,而间断低氧习服组NOS活和下降不明显 (P >0 .0 5 )。急性低氧组与低氧习服组比较 ,前者NOS活力明显低于后者 (P <0 .0 1)。低氧时NOS催化反应平衡常数出现左移。结论 :低氧时NO水平及NOS活力下降 ,经低氧习服后 ,NO水平及NOS活力可明显改善 ;NOS催化反应平衡常数发生变化是NO水平及NOS活力下降的原因之一。

To study the changes of NO and NOS in rats during hypoxia and discuss its mechanism.Methods:The 24 rats(weight 180g～220g) were divided into three groups:normal control group(NC),intermittent hypoxia acclimatization group(IH:exposed to a simulated altitude of 3 000m for 2 weeks,4hours each day,and then exposed to a simulated altitude of 5 000m for 2weeks,4 hours each day)and acute hypoxia group(AH:exposed to a simulated altitude of 5 000m for 4 hours).NO,NOS and NOS equivalent coefficience (Keq)in brain and lung were measured.Results:As compared with NC group,the levels of NO in IH and AH groups was lower(P<0.01);The activity of NOS in AH group had a remarkable drop(P<0.01),but it decreased lightly in IH group (P>0.05).There was obviously different activity of NOS between IH and AH group(P<0.01).NOS Keq was found on the decrease during hypoxia.Conclusions:In hypoxic condition,the level of NO and activity of NOS were decreased,but they were significantly enhanced after the intermittent hypoxia acclimatization;the change of NOS Keq was one of the important factors that leaded to the decrease of NO and NOS during hypoxia.