The Clinical And Experimental Study To The Protective Effect Of Oxytocin On Lung Ischemia-reperfusion Injury Caused By Postpartum Hemorrhagic Shock

Objective To investigate the protective effect and mechanism of oxytocin on lungischemia-reperfusion injury caused by postpartum hemorrhagic shock.Methods Clinical observation:12patients who had suffering form postpartumhemorrhagic shock and disseminated intravascular coagulation received anti-shocktreatment and intravenous infusion of oxytocin.12patients were randomly divided into2groups by the different dose of oxytocin: theⅠgroup（40U）、the theⅡgroup（80U）,carprost and hemabate were given when the poor uterine contractions occured. Toaccount the volume of infusion, and to note the number of patients who used carprostand hemabate.6h after the stable vital sign, the arterial blood samples of each groupwere tested for gas analysis （pH、PaO₂、PaCO₂、HCO₃-）. The venous blood were testedfor the detection of the white cell count, the interleukin-8（IL-8） content, the tumornecrosis factor-α （TNF-α） content, the superoxide dismutase （SOD） activity, themyeloperoxidase （MPO） activity and the malondialdehyde （MDA） content. Experimentstudy:24pregnant SD rats were randomly divided into3groups （n=8each）: Controlgroup （C group）, I/R group and OT treated group （OT group） to establish a lungischemia-reperfusion injury model of pregnant rats with postpartum hemorrhagic shock.The rats of the OT group received uterine-incision delivery and received oxytocin（2U/kg） intraperitoneally at10min before ischemia and0、30、60min after reperfusion. TheI/R group received uterine-incision delivery and received physiological saline at thesame time point. The C group merely received uterine-incision delivery.2h、6h afterreperfusion, the arterial blood samples of each group were tested for gas analysis （pH、PaO₂、PaCO₂、HCO₃-）. Rats were killed at6h after reperfusion, the lungs were removedfor the detection of the lung wet/dry ratio （W/D）, the SOD activity, the MPO activityand the MDA content. The pathological changes were also observed by HE staining. Results Clinical observation: there was no significant difference between the twogroups in the volume of infusion, and the number of patients who used carprost andhemabate.6h after the stable vital sign, the PaO₂of theⅡgroup was significantly higherthan that of theⅠgroup （P <0、05）. However, the difference between the two groups inpH、PaCO₂、HCO₃-was not significant. The white cell count of Ⅱgroup wassignificantly lower than those of theⅠgroup （P <0、01）. The IL-8and TNF-α contentof Ⅱgroup were significantly lower than those of theⅠgroup （P <0、05）. The MDAcontent and MPO activity in theⅡgroup were significantly higher and the SOD activitywas lower than those in theⅠgroup （P <0、01）. Experiment study: The PaO₂of the I/Rgroup and OT group were significantly lower than those of the C group at2h、6h afterreperfusion （P <0、01）, but the OT group was markedly higher than the I/R group （P <0、05）. However, there was no significant difference among the three groups in pH、PaCO₂、HCO₃-. The W/D of lung of I/R group and OT group were significantlyhigher than those of the C group （P <0、05）. The OT group obviously reduced theindexes above （P <0、05）. The pathologic results showed that the lung tissue structureof the C group was normal. In the lung tissue structure of the I/R group, there weremore exudation, interstitial inflammatory infiltration and edema than the OT group. TheMDA content and MPO activity of the I/R group and OT group were significantlyhigher and the SOD activity was lower than those of the C group （P <0、01）. Bycontrast to the I/R group, the MDA content and MPO activity of the OT groupsignificantly reduced, and the SOD activity increased （P <0、01）.Conclusion It is suggested that oxytocin could protect the lungischemia-reperfusion injury caused by postpartum hemorrhagic shock possibly throughits anti-oxidation effects and its inhibition of the infiltration of neutrophils.80U ofoxytocin had the most obvious protective effect.