Impact Of BKca Channel In Prostate Smooth Muscle Cells On The Membrane Potential In Rats With Chronic Abacterial Prostatitis

Objective:To investigate the change of membrane potential caused by BKca channel in the prostate smooth muscle cells of SD rat with chronic abacterial prostatitis (CAP) and evaluate its effect in CAP.Methods:40male SD rats (weight200-255g) were randomly divided into chronic prostatitis model group and normal control group. CAP rat models were established by castration. When the incision heal well a week later, each rats were injected by17-β estrogen (0.25mg/kg*30d), while the normal control group by physiological saline(0.6ml*30d). Rats were executed by CO2inhalation and the prostate tissue was acquired under aseptic conditions. Then we removed the prostate capsule and the surrounding fat, blood vessels, and other tissue carefully. The relatively pure prostate tissue was divided in two, one part was used for cell culture while the other part was sliced and observed after HE staining. PSMCs were cultured and purified in vitro and immunocytochemistry staining was used to identify the expression of specific smooth muscle antibody. Loading with DiBAC4, a sensitive probe for measuring cellular membrane potential, the PSMCs membrane potential was dynamic and quantitative observed by the laser confocal microscopy (LSCM) system.Results:A large number of spindle-shaped and polygonal cells were cultured in vitro, the cells grew as a whirlpool when became confluent, accorded with the growth characteristic of smooth muscle, and immunocytochemistry staining result confirmed the PSMCs with positive expression of a-SMA. The hyperpolarization effect was spotted both in the inflammation group and normal control group after the increased extracellular calcium ion concentration ([Ca2+]。) and then the aviation of BKca channel upon PSMCs cell membrane. This effect can be weakened by Iberiotoxin (IbTX), a specific blocker of BKca channel. But the amplitude of the hyperpolarization is obviously lower in the inflammation group than in the control group. The mean fluorescence intensity change of the two group is18.78±2.92and38.85±7.10, respectively,(P<0.05, n=20), while the IbTX group is1.61±0.46and6.12±1.32, respectively (P<0.05, n=20).Conclusion:The significant reduction of BKca mediated hyperpolarization effect in CAP group, may cause reduction of the regulation ability of cellular membrane potential and the suppression capacity of smooth muscle cell excessive contraction, which lead to pelvic pain syndrome and lower urinary tract symptoms in CAP.