Expression And Significance Of CPI-17Pathway In Myometrium In Atonic Postpartum Hemorrhage

ObjectiveTo investigate the effects of Go6976（inhibitor of PKCα/β）， LY333531（PKCβinhibitor）and Y-27632（Rho kinase inhibitor）on spontaneous oscillatory contractilityand oxytocin-induced contraction potentiality of myometrial strips from patients withatonic postpartum hemorrhage（PPH），and to investigate the expression of relatedmolecules with CPI-17pathway in myometrium of patients with atonic PPH anddiscuss their roles in the pathogenesis of atonic PPH.Methods30women with atonic PPH as study group and30women without PPH as controlgroup participated in this study. All were admitted to Fujian Maternity and ChildrenHealth Hospital for delivery from November2010and December2011.The myometrial strips were adopted to investigate the inhibitory effects onspontaneous oscillatory contractility by adding10-6mol/LGo6976，10^-6mol/LLY333531and10^-5mol/L Y-27632with isometric tension recording，respectively；Meanwhile，the effects of LY333531and Y-27632on oxytocin inducedcontraction potentiality of myometrial strips were observed following atonic PPH，respectively.Real-time fluorescence quantification reverse transcription-polymerase chainreaction and western blotting were applied to detect the expression of CPI-17mRNAand p-CPI-17（Thr38）protein in myometrial tissue；PepTag Non-Radioactive PKCAssay and western blotting were applied to detect PKC activities and p-MYPT-1（Thr696） protein（as Rho kinase activities）in myometrial tissue，respectively；The correlation between the activities of PKC and Rho kinase and the expression ofp-CPI-17（Thr38）protein，and between the activities of PKC and Rho kinase，the expression of p-CPI-17（Thr38）protein and contraction activity，blood loss within thefirst24hours after delivery were analyzed.Results1. Blood loss within the first24hours after delivery and the frequency，amplitudeand activity of myometrial spontaneous oscillatory contractility in study groupwere lower than in control group（P<0.05）.2. The inhibitory effects of Go6976，LY333531and Y-27632on amplitude andactivity of myometrial spontaneous oscillatory contractility in study group weresignificantly lower than in control group（P<0.05）.3. Contraction potentiality induced by oxytocin in myometrial strips followingatonic PPH was significantly decreased （P<0.05），LY333531and Y-27632furtherdecreased contraction potentiality induced by oxytocin in myometrial stripssignificantly following atonic PPH（P<0.05）.4. There was no significant difference in CPI-17mRNA expression between twogroups（P>0.05）；lower level of p-CPI-17（Thr38） protein expression was foundin the study group than in the control group（P<0.05）.5. PKC activities and Rho kinase activities in myometrial tissue in study group weresignificantly lower than in control group（P<0.05）.6. PKC activities and Rho kinase activities in myometrial tissue were positivelyrelated to the expression of p-CPI-1（7Thr38）protein；PKC activities，Rho kinaseactivities and the expression of p-CPI-17（Thr38）protein in myometrial tissuewere positively related to contraction activity；PKC activities，Rho kinaseactivities and the expression of p-CPI-17（Thr38）protein in myometrial tissuewere negatively related to blood loss within the first24hours after delivery.Conclusions1. The spontaneous contractility and contract potentiality induced by oxytocin ofmyometrial strips from atonic PPH women were lower significantly than that ofwomen without PPH.The findings suggest the reactivity to oxytocin in atonicPPH women were poorer than in women without PPH. 2. In atonic PPH women，the inhibitory effects of Go6976，LY333531and Y-27632on amplitude and activity of myometrial spontaneous oscillatory contractilitywere significantly lower than in women without PPH. LY333531and Y-27632further decreased contraction potentiality induced by oxytocin in myometrialstrips significantly following atonic PPH. These findings suggest that PKCα，PKCβ and Rho kinase exert a effect on human myometrial tissue and may beinvolved in the pathogenesis of atonic PPH.3. There were correlations among p-CPI-17（Thr38） protein expression，PKCactivities，Rho kinase activities and contraction activity，blood loss within the first24hours after delivery. These findings implied that CPI-17phosphorylation，andPKC activities，Rho kinase activities could regulate myometrial contractility.4. The expression of p-CPI-17（Thr38）protein in atonic PPH women were lowerthan in women without PPH and may play an important role in pathogenesis ofatonic PPH.5. PKC activities in atonic PPH women were lower than in women without PPH，and PKC activities were strongly correlated with contraction activity. Thesefindings suggest that the interruption of PKC/CPI-17pathway may be involved inthe pathogenesis of atonic PPH.6. Rho kinase activities in atonic PPH women were lower than in women withoutPPH，and Rho kinase activities were strongly correlated with contraction activity.There findings show that Rho kinase/CPI-17pathway may play an important rolein the pathogenesis of atonic PPH.