摘要目的 观察左向右分流致高肺血流肺动脉高压大鼠肺动脉平滑肌细胞( PASMC)膜上电压门控性钾通道(Kv通道)电生理改变,并分析其在肺动脉高压形成过程中的作用.方法 SD大鼠40只,随机分成3组,正常对照组10只,假手术组10只,模型组20只.分别测定肺动脉平均压(mPAP)和右心室肥厚指数(RVHI),急性酶分离法分离出单个PASMC,应用膜片钳技术测定各组大鼠PASMC上Kv通道静息膜电位(Em)、膜电流及电流密度的改变,比较电流-电压曲线的变化.并对以上数据结果进行相关性分析.结果 ①模型组的mPAP和RVHI均高于正常对照组及假手术组,差异有统计学意义(P均＜0.01)；②模型组膜静息电位[(- 33.00±4.09)mV]较假手术组[(-51.11±3.66)mV]及正常对照组[(-48.10±4.54)mV]高,差异具有统计学意义(p均＜0.01)；③Kv通道电流(在+50 mV电压刺激时的峰值电流):模型组峰值电流为(64.80±8.40) pA/pF,较假手术组[(118.03±10.18) pA/pF]及正常对照组[(120.85±11.66) pA/pF]少,差异具有统计学意义(P均＜0.01)；④模型组的电流-电压曲线较假手术组及正常对照组向右下移,差异有统计学意义(P＜0.01).而正常对照组与假手术组相比,以上各值差异没有统计学意义(P＞0.05)；⑤静息(Em)与mPAP、RVHI呈显著正相关关系,而膜电流、电流密度与mPAP、RVHI、静息Em均呈显著负相关关系(P均＜0.001).结论 在左向右分流诱导高肺血流肺动脉高压形成过程中,其PASMC膜上Kv通道功能受抑制,提示钾离子通道可能参与了高肺血流性肺动脉高压的形成.

abstractsObjective To investigate the electrophysiological changes of voltage-gate potassium channel (Kv) of pulmonary arterial smooth muscle cells of pulmonary arterial hypertension in rats induced by left to right shunt,and to analyze the role of Kv during the progress of pulmonary arterial hypertension.Methods Forty male SD rats were randomly divided into three groups,group A ( control,n =10),group B (sham operated only group,n =10),and group C ( PAH model group,n =20).Mean pulmonary artery pressure (mPAP) and right ventricular hypertrophy index (RVHI) of each rat were measured,single pulmonary artery smooth muscle cell (PASMC) was obtained by acute enzyme separation method (collagenase Ⅰ plus papain) and the conventional whole-cell patch clamp technique was used to record resting membrane potential ( Em),potassium ion current of voltage-gated potassium channel,the I-V curve between each 2 groups was compared,and correlation of each parameter was analyzed.Result ① The mPAP and RVHI of group C were significantly higher than those of group A and group B ( P ＜ 0.01,respectively).② The Em of group C [ ( - 33.00 ± 4.09 ) mV ] was significantly higher than that of group A [ ( -48.10 ±4.54) mV] and group B [ ( -51.11 ±3.66) mV],P＜0.01.③ The peak current at +50mV of voltage-gated potassium channel:in group C [ ( 64.80 ± 8.40 ) pA/pF ],it was significantly lower than that of group A [ ( 120.85 ± 11.66 ) pA/pF ] and group B [ ( 118.03 ± 10.18 ) pA/pF ] ( P ＜ 0.01,respectively).None of the parameters showed any significant difference between group A and group B (P ＞0.05 for all comparisons).④ Compared with group A and group B,the I-V curve of group C significantly downward shifted (P ＜0.01,respectively).The difference in I-V curve between group A and group B was not significant,P ＞0.05.⑤The correlation of resting membrane potential and mPAP and RVHI had significantly positive correlation ( P ＜ 0.001,respectively ) ; but the correlation of membrane current,membrane current density and mPAP,RVHI and resting membrane potential had significantly negative correlation (P ＜ 0.001,respectively).Conclusion During the formation process of left-to-right shunt induced pulmonary arterial hypertension,function of Kv channel was inhibited,suggesting that Kv channel may be the mechanism of pulmonary arterial hypertension induced by left-to-right shunting.