清醒羊血浆PAF在低氧性肺动脉高压产生及逆转中的变化

本实验复制清醒羊低氧性肺动脉高压模型，观察肺动脉高压发生发展及逆转过程中血浆内源性血小板活化因子（ｐｌａｔｅｌｅｔａｃｔｉｖａｔｉｎｇｆａｃｔｏｒ，ＰＡＦ）的动态变化。结果表明：（１）低氧４ｄ引起低氧血症，导致肺血管收缩，形成肺动脉高压；停止低氧后可逆转；（２）开始低氧，血中内源性ＰＡＦ升高，但低氧时间延长血浆中ＰＡＦ却不随肺动脉压升高相应增加；（３）停止低氧，血浆ＰＡＦ不随肺动脉高压的逆转而相应降低。上述结果表明血浆ＰＡＦ的变化与肺动脉高压无关。提示血中内源性ＰＡＦ不介导清醒羊低氧性肺血管收缩导致的肺动脉高压。

VARIATION OF PLASMA PLATELET ACTIVATING FACTOR DURING DEVELOPMENT AND REVERSAL OF HYPOXIC PULMONARY HYPERTENSION IN CONSCIOUS SHEEP

A model of hypoxic pulmonary hypertension was made in conscious sheep, and plasma platelet activating factor(PAF)were measured by radioimmuroassay method during the begining, progression and reversal of hypoxic pulmonary hypertension.The main results were as follows: (1) Under hypoxic condition for 4 days, the conscious sheep develops hypoxemia and marked hypoxic pulmonary vasoconstriction (HPV).These response were reversible. (2) At the beginning of hypoxia, plasma PAF increased, but did not continually increase with hypoxic prolongation and development of HPV. (3) Upon cessation of hypoxia with reversal of pulmonary hypertension, plasma PAF did not show any parallel decrease. These results indicate that plasma PAF is in no way involves in the development of HPV in conscious sheep.