The Changes Of BKCa In Vascular Smooth Muscle Cells Of Human With Severe Preeclampsia Placental Small Arteries

Objective:The VSMCs participate in the contraction of bloodvessels. The previous studies indicated that BKCaplays vital role in thecontraction and relaxation of vascular. In this study, we use Patch Clamptechnique to record the activities of BKCachannels in VSMCs of patientswith SPE, study these changes, then compare with the activities of BKCain VSMCs of normal pregnant, and learn the relationship between SPEand ion channels, it is desirable to provide atheoretical basis for thepathogenesis of disease and treatment. Methed:(1)We selected a controlgroup with10patients that met the severe cases of preeclampsiadiagnostic criteria, at the same time, choose a normal pregnant group of10patients with no pregnancy complications and comorbidities. Thesmall arteries of placenta were dissociated immediately ofter vaginaldelivery or cesarean section delivery.Part of placental small artery use HEstaining to observed the difference between placental small arteryvascular smooth muscle cells and severe preeclampsia placenta smallchanges in vascular smooth muscle cells under the microscope.(2)Keepthe enzymatically dissociated VSMCs of human placenta into40Crefrigerator for2to4hours before experiment.(3)The smooth,well-striated myocytes were chosen for single-channel patch clamp experiment.(4)Clampex10.1software and Clampfit10.1software wereused for data acquisition and data analysis individually. We recorded andcompared the Amp, NPO,To, Tcof BKCachannels from severepreeclampsia group and the control group, and fitted the Amp histogramfunction of whole points. The morphological identification of Humanplacental small artery vascular smooth muscle cells:The acute enzymeisolated VSMCs of human placental were single kind and easy todistinguish. The identification of human placental vascular smoothmuscle cells of the small arteries was thought to provide the basis for nextexperiments. The characteristics of BKCachannels in VSMCs of humanplacental small artery were as follows:(1)The channel could be blockedby IbTX specially;(2)The unitary conductance of BKCachannel was241.25+20ps (n=10);(3)The channel was calcium sensitive;(4)Thechannel was voltage dependent. Result: The volume of VSMCs ofSevere preeclampsia group become large apparently, loose lightly stained,the light of patina is soft, many foam cells appear and acuteatherosclerotic changes。When the Test voltage was40mV, the Amp ofBKCachannels from SPE group was4.770+1.128pA; The NPO, To and Tcwere0.006+0.002,3.991+1.386ms, and791.893+270.693msindividually.However, the Amp, Npo, To and Tc of BKCachannels fromcontrol group were7.407+0.881pA,0.021+0.006,5.764+0.801ms,279.330+69.903ms. There were statistical significant difference for Amp, NPo, Tc and Tc (P<0.05). Conclusion:Placental vascular atherosclerosis,this cause placental ischemia, hypoxia, and take part in the process ofsevere pre-eclampsia pathology. The Amp and NPo of BKCachannels inVSMCs of patients with SPE placental small artery were decreased, Toshortened and Tc prolongated. The function of BKCachannels in VSMCsof placental small artery was reduced, this could lead to vasoconstrictionand increase blood pressure, involved in the change of utero-placentalchemia and hypoxia, may be associated with the pathogenesis ofhypertensive disorders in pregnancy.