Heme oxygenase vs. nitric oxide synthase in signaling mediating sildenafil citrate action
Heme oxygenase vs. nitric oxide synthase in signaling mediating sildenafil citrate action
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DOI：
10.1111/j.1743-6109.2007.00533.x
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发表时间：
2007-07-01
影响因子：
3.5
通讯作者：
Mahfouz, Soheir
中科院分区：
文献类型：
--
作者：
Aziz, M. Talaat Abdel;El-Asmer, Mohamed Farid;Mahfouz, Soheir
导论.血红素加氧酶（HO）催化血红素氧化降解为胆绿素和一氧化碳（CO）的限速步骤。CO与一氧化氮（NO）有许多共同的特性，包括鸟苷酸环化酶的激活、信号转导和基因调控。评估介导海绵体组织对枸橼酸西地那非摄入反应的信号通路。主要结果指标。在解剖的海绵状组织中;采用逆转录聚合酶链反应（RT-PCR）检测HO-1、HO-2和nNOS基因表达，HO酶活性测定，Western blot检测HO-1、HO-2蛋白表达，酶联免疫吸附试验（ELISA）检测组织环磷酸鸟苷（cGMP）水平，组织病理学检查。将240只SD大鼠分为5组：第1组，正常对照组;第2组，枸橼酸西地那非4 mg/kg经口给药组;第3组，西地那非加HO诱导剂二阿魏酰甲烷组;第4组，西地那非加HO抑制剂锌原卟啉组;第5组，西地那非kg经口胃管给药组。第3组接受相同剂量的西地那非加HO诱导剂，加一氧化氮合酶抑制剂L-硝基精氨酸甲酯。分别于1/2、1、2、3 h后处死大鼠，每组1/2只。HO-2基因在各组中均表达。HO-1在对照组中不表达，在Gr 2中表达，在Gr 3中增强，在Gr 4和5中减弱。这些结果通过Western blot证实。nNOS在对照组中表达，在Gr 2和3中增加，在Gr 4和5中减少。HO酶活性和cGMP水平在Gr 2中显著升高，在Gr 3中加重，而在Gr 4和5中显著降低。病理切片显示2级海绵体组织血管扩张，3级海绵体组织血管扩张增强。枸橼酸西地那非的作用可能是通过上调HO-1基因表达介导的。
Introduction. Heme oxygenase (HO) enzyme catalyzes the rate limiting step in oxidative degradation of heme to biliverdin and carbon monoxide (CO). CO has been shown to share many properties with nitric oxide (NO), including activation of guanyl cyclase, signal transduction, and gene regulation.Aim. To assess the signaling pathways mediating cavernous tissues response to sildenafil citrate intake experimentally.Main Outcome Measures. In dissected cavernous tissues; detection of HO-1, HO-2 and nueronal nitric oxide synthase (nNOS) gene expressions by reverse transcriptase polymerase chain reaction (RT-PCR), HO enzyme activity assay, HO-1, HO-2 protein detection by Western blot, cyclic guanosine monophosphate (cGMP) tissue levels by enzyme linked immunosorbent assay (ELISA) and histopathology.Methods. Two hundred forty Sprague-Dawley rats divided into five equal groups were investigated: group (Gr) 1, controls received regular diet; Gr 2, received sildenafil citrate 4 mg/kg orally; Gr 3, received the same dose of sildenafil added to HO inducer, diferuloylmethane; Gr 4, received sildenafil added to HO inhibitor, zinc protoporphyrin, and Gr 5, received sildenafil kg orally by gastric tube. Gr 3 received the same dose of sildenafil added to HO inducer, added to nitric oxide synthase inhibitor, L-Nitroarginine methylester. Twelve rats from each group were sacrificed by cervical dislocation successively after 1/2, 1, 2, and 3 hours from the intake.Results. HO-2 gene expression was demonstrated in all groups. HO-1 was not expressed in controls, expressed in Gr 2, accentuated in Gr 3, and attenuated in Gr 4 and 5. These results were confirmed by Western blot. The nNOS was expressed in controls, increased in Gr 2 and 3, and decreased in Gr 4 and 5. HO enzyme activity and cGMP levels were significantly elevated in Gr 2, accentuated in Gr 3, and significantly decreased in Gr 4 and 5 compared to controls. Vasodilatations were observed in cavernous tissues of histopathologic sections of Gr 2 and increased in those of Gr 3.Conclusions. Sildenafil citrate actions may be mediated by up-regulation of HO-1 gene expression.