Boesch S T, Corvin S, Zhang J, Rogatsch H, Bartsch G, Klocker H
Department of Urology, University of Innsbruck, Austria.
Prostate. 1999 Jun 1;39(4):226-33. doi: 10.1002/(sici)1097-0045(19990601)39:4<226::aid-pros2>3.0.co;2-8.
Prostatic stromal cells are believed to be a key factor in the pathogenesis of benign prostatic hyperplasia (BPH). The effect of phenylephrine, an alpha1-adrenergic receptor agonist, and doxazosin, an alpha1-adrenergic receptor-specific antagonist, on the expression of smooth muscle myosin-heavy-chain isotypes SM-1 and SM-2 was tested in an in vitro model of prostatic smooth muscle cells (SMC).
Primary prostatic stromal cells, grown in SMC-specific medium, were treated with 10 microM of phenylephrine or 1 microM of doxazosin or a combination of both. SM-2 to SM-1 mRNA ratios and expression of alpha1-adrenergic receptor subtypes were determined by means of reverse transcriptase polymerase chain reaction (RT-PCR) techniques. Cell growth was measured by a cell viability assay.
SM-1 mRNA and only very low levels of SM-2 mRNA were detected in prostatic SMC cultures grown for 4 days in a serum-free base medium. After 6 days of treatment, SM-2 expression increased, highest in the doxazosin-treated cultures. In comparison to unstimulated cells, a statistically significant 10-fold increase of the SM-2:SM-1 ratio was measured in doxazosin-treated cultures. Analysis of alpha1-adrenergic receptor subtype expression revealed the presence of mRNAs of subtypes 1d and 1b mRNAs. Subtype 1a was not expressed. Phenylephrine and doxazosin showed no significant effect on cell proliferation and on alpha1d-adrenergic receptor expression.
SMC can differentiate from a proliferative to a contractile phenotype, which is accompanied by increased expression of isotope 2 of smooth muscle myosin heavy chain. Our results suggest that doxazosin seems to have a long-term effect on the differentiation of prostatic stromal cells, indicating that alpha1-adrenergic receptor antagonists do not act solely on SMC contractility.
前列腺基质细胞被认为是良性前列腺增生（BPH）发病机制中的关键因素。在前列腺平滑肌细胞（SMC）的体外模型中，测试了α1肾上腺素能受体激动剂去氧肾上腺素和α1肾上腺素能受体特异性拮抗剂多沙唑嗪对平滑肌肌球蛋白重链同型异构体SM-1和SM-2表达的影响。
在SMC特异性培养基中培养的原代前列腺基质细胞，用10微摩尔的去氧肾上腺素或1微摩尔的多沙唑嗪或两者的组合进行处理。通过逆转录聚合酶链反应（RT-PCR）技术测定SM-2与SM-1 mRNA的比率以及α1肾上腺素能受体亚型的表达。通过细胞活力测定法测量细胞生长。
在无血清基础培养基中培养4天的前列腺SMC培养物中检测到SM-1 mRNA，而SM-2 mRNA水平极低。处理6天后，SM-2表达增加，在多沙唑嗪处理的培养物中最高。与未刺激的细胞相比，多沙唑嗪处理的培养物中SM-2:SM-1比率在统计学上显著增加了10倍。对α1肾上腺素能受体亚型表达的分析显示存在1d和1b亚型的mRNA。未表达1a亚型。去氧肾上腺素和多沙唑嗪对细胞增殖和α1d肾上腺素能受体表达无显著影响。
SMC可以从增殖表型分化为收缩表型，这伴随着平滑肌肌球蛋白重链同型异构体2表达的增加。我们的结果表明，多沙唑嗪似乎对前列腺基质细胞的分化有长期影响，表明α1肾上腺素能受体拮抗剂并非仅作用于SMC收缩性。
