慢性非细菌性前列腺炎大鼠前列腺平滑肌细胞BKCa通道对膜电位的影响

目的:探讨慢性非细菌性前列腺炎(CAP)SD大鼠前列腺平滑肌细胞(PSMCs)BKCa通道对细胞膜电位的影响及其在CAP中的意义。方法:将40只雄性SD大鼠随机分为CAP模型组和正常对照组,去势加雌激素注射方法诱导CAP模型,体外组织块贴壁法培养并纯化PSMCs,细胞经膜电位敏感的荧光染料DiBAC4孵育后在激光共聚焦显微镜(LSCM)下动态定量观察激活BKCa通道所引起的膜电位变化。结果:细胞外钙离子浓度升高,激活BKCa通道使CAP组与正常对照组PSMCs细胞膜均发生超极化,两组效应均能被BKCa通道特异性阻滞剂Iberiotoxin(IbTX)阻断而减弱。但CAP组超极化幅度明显减低,两组细胞超极化效应引起的DiBAC4荧光强度变化值分别为18.78±2.92、38.85±7.10(P<0.05,n=20),经IbTX作用后两组细胞DiBAC4荧光强度变化值分别为1.61±0.46、6.12±1.32(P<0.05,n=20),差异有显著性。结论:CAP组SD大鼠PSMCs细胞膜BKCa通道介导的超极化效应明显减弱,可能导致其对膜电位的调节能力及抑制平滑肌细胞过度收缩能力降低,从而引起CAP盆腔疼痛综合征及下尿路症状。

Impact of BKCa channel in prostate smooth muscle cells on the membrane potential in rats with chronic abacterial prostatitis

Objective: To investigate the impact of the BKCa channel in prostate smooth muscle cells(PSMCs) on the membrane potential in SD rats with chronic abacterial prostatitis(CAP).Methods: CAP models were established in 20 SD rats by castration and injection of 17 β-estrogen,and another 20 were taken as normal controls.PSMCs were cultured and purified in vitro,and treated with DiBAC4,followed by quantitative observations on the dynamic changes of the cell membrane potential by laser confocal microscopy.Results: The extracellular calcium ion concentration(o) was increased and the BKCa channel was activated,which induced the hyperpolarization of the PSMC membrane in both the CAP models and normal control rats.This effect was weakened with Iberiotoxin(IbTX),a specific blocker of the BKCa channel,but the amplitude of the hyperpolarization was obviously lower in the CAP than in the control group.The DiBAC4 fluorescence intensity induced by hyperpolarization was 18.78±2.92 in the former and 38.85±7.10 in the latter(P<0.05),while that induced by IbTX was 1.61±0.46 and 6.12±1.32(P<0.05),respectively.Conclusion: Significant decrease of BKCa-mediated hyperpolarization in the CAP model can reduce its abilities of regulating the membrane potential and suppressing the excessive contraction of PSMCs,which may result in pelvic pain syndrome and lower urinary tract symptoms.