间断低氧对大鼠下丘脑超微结构及前增食欲素水平的影响

目的探讨睡眠中间断低氧对大鼠下丘脑前增食欲素及受体水平的影响以及下丘脑超微结构的变化。方法大鼠分成对照组、间断低氧组和持续低氧组,分别给予吸入空气,持续低氧和间断低氧气体,并在实验开始后1d、3d、1w和4w应用RT-PCR方法测定大鼠下丘脑前增食欲素及受体水平,分析其间的变化关系,电镜观察下丘脑的超微结构变化。结果与对照组和持续低氧组比较,间断低氧4w后大鼠下丘脑前增食欲素mRNA水平明显降低,受体水平升高,但在持续低氧和对照组之间无明显差异。在低氧后1d、3d、7d后大鼠下丘脑前增食欲素mRNA降低,受体水平升高,在4w后,持续低氧组则接近正常。急性持续低氧大鼠超微结构变化更严重,而慢性间断低氧变化更持久。结论慢性间断低氧可以引起下丘脑前增食欲素下降及受体水平升高,急性持续低氧也可引起上述变化,而慢性持续低氧未引起增食欲素改变;慢性间断低氧大鼠下丘脑超微结构表现为严重而持久的变化。

THE EFFECT OF INTERMITTENT HYPOXIA ON ULTRASTRUCTURE AND PREPO-OREXIN LEVEL IN RAT HYPOTHALAMUS

Objective To study the changes of prepo-orexin and it's receptor (OXR) in rat hypothalamus sabjected to intermittent hypoxia during sleep,and to observe the ultrastructural changes of the hypothalamus.Methods Rats were exposed to intermittent hypoxia(IH),room air(normal control) and continuous hypoxia(CH) respectively,the experiment lasted 4 weeks,the mRNA levels of prepo-orexin and OXR in hypothalami of rats were detected by RT-PCR,while the ultralstructure of the hypothalamus was observed by electron microscopy. Results After 4 weeks the prepo-orexin mRNA levels in rat hypothalamus exposed to intermittent hypoxia were decreased significantly than those exposed to continuous hypoxia as well as normal air(P<0.01),but there was no difference between CH and normal control(P>0.05).After 1 day,3 days,and 1 week,prepo-orexin mRNA levels decreased respectively when compared with those of normal control,but there were no difference between IH and CH.The OXR mRNA levels in rat hypothalamus changed conversely.The ultrastructural changes of the hypothalamus was maintained in In but not in CH.Conclusion Chronic intermittent hypoxia can lead to prepo-orexin reduction and OXR increase.Acute continuous hypoxia can cause the same changes,but chronic CH leads to no significant change in prepo-orexin and maintained seriously damage in ultrastructure.