21d头低位卧床中几种体液调节激素的变化

Variation of Several Volume Regulating Hormones during 21 d -6° Head down Bed Rest.

目的观察卧床模拟失重所致血浆肾素活性（ＰＲＡ）、醛固酮（Ａｌｄ）及前列腺素（ＰＧＩ２）的变化和ＬＢＮＰ对抗措施对上述激素的影响。方法１２名健康男性志愿者进行了２１ｄＨＤＴ－６°卧床实验。被试者年龄２３．７±５．０岁，随机等分为对照组（ＣＯＮ）和下体负压（ＬＢＮＰ）组。ＬＢＮＰ组在卧床最后一周进行下体负压锻炼（－３０ｍｍＨｇ，１ｈ／ｄ）。卧床前、卧床第２、４、１１天及卧床结束日清晨分别抽取肘静脉血。结果与卧床前相比，Ａｌｄ在第２天显著下降（ＣＯＮ－３０％，Ｐ＜０．０５；ＬＢＮＰ－３８％，Ｐ＜０．０１），在第１１天显著上升（ＣＯＮ＋３０％，Ｐ＜０．０５；ＬＢＮＰ＋４８％，Ｐ＜０．０１）。ＰＲＡ在第４天达到峰值（Ｐ＜０．０５），第２２天回落到低于对照水平。ＰＧＩ２在ＨＤＴ过程中均高于对照水平。对照组在第２２天增加＋２６０％（Ｐ＜０．０１），ＬＢＮＰ组在第１１天，第２２天分别升高１４９％，１０２％（Ｐ＜０．０５）。采用ＬＢＮＰ对抗措施后，ＰＲＡ，Ａｌｄ在两组间无明显差别，ＰＧＩ２在ＬＢＮＰ组未进一步升高。结论２１ｄ头低位卧床导致ＰＲＡ、Ａｌｄ的一过性升高及ＰＧＩ２持续性升高。

Objective To investigate variations of plasma renin activity(PRA),aldosterone (Ald) and prostaglandin I 2 (PGI 2) during 21d -6° head down tilt (HDT) with and without lower body negative pressure (LBNP). Method -6°head down tilt for 21d were used to simulate weightlessness.12 healthy male, aged 23.7±5.0, were equally and randomly divided into control group (CON) and LBNP group.The latter subjected to LBNP (-30mm Hg,1h/d) in the last week of HDT. Samples of plasma were taken before HDT and on the 2nd,4th,11th and 22nd day during HDT. Result Compare to control levels, Ald declined significantly on the 2nd (CON -30%,P<0.05;V.S.LBNP -38%,P<0.01),and increased significantly on the 11th day(CON +30%,P<0.05;LBNP +48%,P<0.01).PRA reached peak value on the 4th day(P<0.05),and declined to below the control level on the 22nd day.PGI 2 increased constantly during HDT,and increased significantly on the 22nd day (CON P< 0.01 ),11th,22nd (LBNP P<0.05). No apparent difference was found between groups after LBNP concerning PRA and Ald;and PGI 2 didn't increase further in LBNP group. Conclusion HDT induced a timely increasing in PRA and Ald , constant increasing in PGI 2.