内源性一氧化碳对血管紧张素Ⅱ诱导的大鼠血管平滑肌细胞增殖的抑制作用

目的　研究内源性一氧化碳 (CO)对血管紧张素 (Ang )诱导的大鼠血管平滑肌细胞 (VSMC)增殖的影响。方法　体外培养 Wistar大鼠主动脉 VSMC,用 Ang 诱导其增殖 ,分别用血红素氧合酶 1(HO- 1)的诱导剂和阻断剂 ,以诱导和阻断 HO- 1。通过酶联免疫法及同位素技术分别检测培养上清液中碳氧血红蛋白 (COHb)含量及VSMC3H-胸腺嘧啶核苷 (3H - Td R)掺入量。结果　氯血红素 (Hm )显著增高培养上清液中 COHb,对由 Ang 诱导的 VSMC3H - Td R掺入量的增高有显著抑制作用。结论　内源性 CO对 Ang 刺激的 VSMC的增殖有显著抑制作用。提示 HO- CO系统在血管成形术后再狭窄的发生和发展中有一定作用     

缺氧对大鼠主动脉平滑肌细胞增殖的实验研究

目的探讨缺氧对培养的大鼠主动脉平滑肌细胞(VSMCs)增殖的影响及其可能机制.方法分别在常氧和缺氧12、24、48 h条件下体外培养大鼠VSMCs,应用3H-TdR掺入实验和MTT比色法检测细胞增殖情况,流式细胞术测定细胞周期,同时用免疫细胞化学法检测缺氧对增殖细胞核抗原(PCNA)和核转录因子NF-κB蛋白表达的影响.结果 VSMCs在缺氧时对3H-TdR摄取量、MTT比色吸光度A值、细胞周期中S期和G2/M期细胞百分比、PCNA和NF-κB蛋白表达明显高于常氧组(P<0.05或P<0.01).结论缺氧可诱导VSMCs增殖,促使细胞进入有丝分裂期,增强PCNA和NF-κB蛋白表达可能是其重要机制之一.     

姜黄素诱导血红素氧合酶-1表达抗大鼠主动脉平滑肌细胞增殖作用的研究

目的:探讨姜黄素诱导大鼠主动脉平滑肌细胞(RASMC)血红素氧合酶-1(HO-1)表达效果及其抗细胞增殖的作用.方法:RASMC株经复苏、传代培养后分组实验,分别加用不同浓度的姜黄素或姜黄素 ZnPPⅨ孵育,用Western blot法检测HO-1表达效果;用四唑氮法及3H-Td掺入法检测RASMC增殖情况;同时还观察了姜黄素的细胞毒性作用.结果:姜黄素能呈剂量依赖性诱导RASMC高表达HO-1蛋白并显著抑制血清刺激的RASMC增殖(P＜0.05或P＜0.01),加入ZnPPⅨ共同孵育能使姜黄素诱导HO-1表达明显降低并消除其对RASMC增殖的抑制作用(均P＜0.01),实验浓度的姜黄素无明显细胞毒性作用(P＞0.05).结论:姜黄素能显著诱导RASMC表达HO-1蛋白并以此有效抑制RASMC增殖.     

腺病毒介导反义AT1R转染对大鼠血管平滑肌细胞增殖的抑制作用

目的观察腺病毒介导反义AT1基因转染对培养的大鼠动脉平滑肌细胞(VSMCs)增殖的影响.方法用定向克隆和同源重组方法构建携带人反义AT1基因的复制-缺陷型重组腺病毒(Ad/CMV*ahAT1),转染体外培养的 VSMCs,用RT-PCR半定量法和免疫组化法检测AT1R的表达,用3H-TdR掺入实验和流式细胞仪检测VSMCs的DNA合成和增殖指数.结果与对照组相比,转染Ad/CMV*ahAT1后48 h的VSMCs,AT1R 的mRNA表达低50%,蛋白表达也显著低于对照组(P<0.01).给予Ang Ⅱ刺激的VSMCs的3H-TdR掺入量和增殖指数明显高于空白对照组(分别为P<0.05和P<0.01);转染Ad/CMV*ahAT1组3H-TdR掺入量和增殖指数则显著降低(与DMEM组比P<0.05,与Ang Ⅱ对照组比P<0.01).结论腺病毒介导的反义AT1R转染,通过抑制AT1R的表达,明显抑制VSMCs的增殖和Ang Ⅱ刺激的VSMCs增殖.     

Ap-1基因RNA干扰对大鼠血管平滑肌细胞增殖的影响

目的探讨Ap-1基因RNA干扰抑制血管平滑肌细胞（VSMCs）基因对VSMCs增殖的影响。方法以Ap-1基因RNA干扰VSMCs基因,应用MTr比色试验检测VSMCs增殖情况,流式细胞仪检测VSMCs细胞周期,免疫细胞化学染色观察增殖细胞核抗原（PCNA）表达。结果siRNA转染后,3个阳性siRNA转染组Ap-1基因表达水平均降低;VSMCs的MTY吸光度值和PCNA表达量均降低;VSMCs出现明显的G0／G1期阻滞。结论RNA干扰介导的Ap-1基因沉寂可显著抑制VSMCs增殖。     

HO-1活性改变对肝癌细胞周期调控因子CKS1和Cyclin D的影响

目的探讨血红素加氧酶(HO)-1活性改变对肝癌细胞株Hep G2细胞周期蛋白(Cyclin)依赖性激酶调节亚基(CKS)1和Cyclin D的影响。方法采用靶向抑制HO-1的小分子RNA(siRNA)沉默细胞癌Hep G2细胞HO-1基因的表达,应用四甲基偶氮唑蓝比色法(MTT)测定Hep G2细胞的增殖情况,应用RT-PCR法测定HO-1、CKS1和Cyclin D mRNA,应用Western印迹检测HO-1、CKS1和Cyclin D蛋白表达水平。结果 MTT实验结果显示,HO-1 siRNA转染组细胞转染后24 h和48 h的吸光度较空白对照组显著降低(P0.01),HO-1 siRNA转染组细胞转染后48 h的HO-1、CKS1和Cyclin D mRNA水平较空白对照组显著降低(P0.01),HO-1 siRNA转染组细胞转染后48 h的HO-1、CKS1和Cyclin D蛋白水平较空白对照组显著降低(P0.01)。结论 HO-1的活性降低可抑制肝癌Hep G2细胞的增殖,其调控作用可能通过降低Hep G2细胞CKS1和Cyclin D表达而实现。     

血管紧张素Ⅰ抑制血管紧张素Ⅱ诱导的血管平滑肌细胞增殖

目的探讨血管紧张素-(1-7)[Ang-(1-7)]对血管紧张素Ⅱ(AngⅡ)诱导的大鼠血管平滑肌细胞(VSMCs)增殖的影响。方法采用组织贴块法培养VSMCs,取生长良好的第3～5代细胞用于实验。随机分为对照组、AngⅡ组、Ang-(1-7)组、AngⅡ Ang-(1-7)组、AngⅡ Ang-(1-7) (A-779)组,通过3H胸腺嘧啶(3H-TdR)掺入法测定VSMCs的DNA合成,用结晶染色的方法检测细胞数目,观察VSMCs的增殖情况。结果①与对照组比,AngⅡ(100nmol/L)孵育细胞24h后可明显诱导VSMCs3H-TdR掺入量增加;Ang-(1-7)(1000nmol/L)可减少3H-TdR掺入量。②与AngⅡ组比较,Ang-(1-7)(10nmol/L、100nmol/L、1000nmol/L)呈浓度依赖性的抑制AngⅡ诱导的VSMCs3H-TdR掺入量。加入Ang-(1-7)特异性受体阻断剂A-779后,Ang-(1-7)此作用消失。③结晶染色结果显示,AngⅡ可诱导VSMCs数目明显增加(P<0.05)。Ang-(1-7)可抑制AngⅡ诱导的VSMCs增加,亦呈浓度依赖性(P<0.05)。结论Ang-(1-7)能抑制基础和AngⅡ诱导的VSMCs增殖,通过其特异性受体发挥作用。     

雷公藤内酯醇对大鼠血管平滑肌细胞的增殖及DNA合成的影响

目的：探讨中药制剂雷公藤内酯醇对培养血管平滑肌细胞（VSMCs）增殖及DNA合成的影响。方法：体外培养大鼠胸主动脉平滑肌细胞，用^3H-TdR掺入率观察该药对细胞增殖和DNA合成的影响，采用流式细胞技术观察该药对细胞增殖周期的影响。结果：雷公藤内酯醇以剂量依赖性方式，抑制VSMCs的DNA合成；阻断细胞周期的中G0/G1期向DNA合成的S期转化。结论：雷公藤内酯醇能够有效地抑制VSMC的增殖，具有潜在的预防再狭窄价值。     

血红素加氧酶-1对慢性肾功能衰竭大鼠高血压的影响

目的 建立大鼠慢性肾功能衰竭高血压模型，研究血红素加氧酶-1(HO-1)对慢性肾功能衰竭大鼠血压的影响，并探讨血红素加氧酶-1在慢性肾衰血压调节中的作用和机制。方法 5／6肾切除法建立慢性肾功能衰竭，大鼠随机分成3组：①正常组，②肾衰组，③Hemin组(肾衰 HO-1诱导剂组)。检测术后第6、8、10周的血压，第10周血清尿素氮、肌酐、血浆和肾组织丙二醛(MDA)，双波长分光光度法测量血浆内源性CO的水平，观察第10周肾脏病理改变，免疫组织化学方法检测肾组织HO-1的表达，应用RT-PCR和Western Blot检测肾组织HO-1 mRNA和蛋白质的表达。结果 诱导慢性肾功能衰竭大鼠体内HO-1表达可以：①明显升高血浆内源性CO水平(P＜0．05)；②减少血浆和肾组织MDA；③明显降低慢性肾功能衰竭大鼠血压(P＜0．01)；④降低血清尿素氮、肌酐(P＜0．01)；⑤减轻肾小球系膜增生、间质损害。结论 HO-1可以通过释放内源性CO和减少血浆氧化应激水平而降低慢性肾衰大鼠血压，此外它还可能具有降压效应以外的肾脏保护作用。     

血红素加氧酶-1表达对HBV复制的反向调控作用

目的评价血红素加氧酶-1（HO-1）对HBV复制的调控作用。方法采用分子克隆的方法分别构建人H（）_1真核表达载体——pH0和HO-1RNA干扰质粒——pHi，同HBV可复制性克隆pHBV1．3体外共转染人肝癌细胞系Huh-7，检测HBV抗原分泌情况和HBV相关mRNA含量。利用HBV急性感染小鼠模型，腹腔注射钴原卟啉（CoPP）IX和锌原卟啉（ZnPP）IX分别诱导和抑制HO-1表达，检测血清HO～1水平、HBV效价，免疫组织化学染色观察HBcAg在肝细胞内表达情况。分别在细胞水平和动物体内水平，评价HO-1表达对HBV复制的调控作用。结果同空载体共转染细胞相比，pHO共转染后HO-1的分泌水平明显上调（P〈0．01），HBsAg／HBeAg的分泌受到抑制（均P〈0．01）；pHi共转染后HO-1的分泌水平下降（P〈0．01），而HBsAg／HBeAg分泌增加（P均〈0．01）；但各组HBV相关RNA水平无明显差异。CoPPIX注射后诱导小鼠血清H0—1高表达（P％0．01），ZnPPIX则有效抑制了HO-1表达（P％0．01）。同对照组相比，CoPPIX组小鼠血清HBVDNA含量降低，肝脏内HBcAg阳性染色信号也随之明显减弱（P均〈0．01）；而ZnPPIX组小鼠血清HBVDNA含量增加，肝脏内HBcAg表达明显增强（均P〈0．01）。结论上调HO-1表达可有效抑制HBV复制，而下调其表达有利于HBV复制，且其可能是在转录后环节上发挥抗HBV作用。     

血红素氧合酶-1及一氧化碳-胆红素系统对心力衰竭大鼠心功能的保护作用

目的探讨经胃肠道给予氯化高铁血红素后.体内血红素氧合酶-1(HO-1)及一氧化碳-胆红素(CO-胆红素)的反应和对大鼠慢性压力负荷性心力衰竭(心衰)进程的影响。方法将成年雄性SD大鼠63只,随机分为血红素组、心衰组和对照组,每组21只。术后3周血红素组以60 mg·kg~(-1)·d~(-1)氯化高铁血红素灌胃,另外2组同时间灌以同体积生理盐水。并分别在4、8、12周检测血清HO-1、碳氧血红蛋白(COHb);测定尾动脉压;经颈动脉插管检测平均动脉压、左心室收缩压(LVSP)、左心室舒张末压(LVEDP)以及左心室压力最大上升速率(+dp/dt_(max))和左心室压力最大下降速率(—dp/dt_(max))。结果与对照组比较,心衰组8、12周时HO-1和COHb含量明显升高(P<0.01);与心衰组比较,血红素组在4、8、12周时HO 1和COHb含量明显升高(P<0.01),8周时尾动脉压、平均动脉压和LVSP明显降低(P<0.01),8、1 2周时LVEDP明显降低(P<0.05,P<0.01),12周时±dp/dt_(max)明显升高(P<0.01)。结论经胃肠道给予氯化高铁血红素可对体内HO-1产生诱导作用;HO-1及CO-胆红素系统的诱导能减缓压力负荷性心衰大鼠心衰的进展,对心脏的收缩和舒张功能有保护作用。     

一氧化碳体系对慢性肺心病大鼠肺血管结构重建的抑制作用

目的　研究内源性一氧化碳体系对慢性肺心病肺血管结构重建的调控作用。方法　将36只SD大鼠随机分为正常对照组 (A组 )、4周低O2 高CO2 组 (B组 ) ,4周低O2 高CO+ 2 血晶素组 (C组 ) ,每组 12只。测定各组大鼠肺动脉平均压 (mPAP)、右心室 / (左心室 +室间隔 )重量比 [RV/ (LV +S) ]、肺细小动脉显微和超微结构、血CO浓度、血清及肺组织匀浆上清液血红素氧合酶 1(HO 1)活性和肺细小动脉HO 1及其基因表达的变化。结果　 (1)B组mPAP为 (2 0 1± 0 8)mmHg(1mmHg =0 .133kPa)、RV/ (LV +S)为 (35 5± 1 7) %、与A组 [(15 3± 1 4 )mmHg、(2 6 7± 1 7) % ]及C组[(16 5± 3 7)mmHg、(30 2± 1 6 ) % ]比较差异有显著性 (P均 <0 0 1)。 (2 )B组肺细小动脉血管结构重建的显微形态测定指标与A、C组比较差异也有显著性 (P <0 0 1)。 (3)B组全血CO含量、血清及肺组织匀浆HO 1活性、肺细小动脉HO 1及其mRNA分别为 (2 1± 0 9) %、(73± 18)nmol·L-1·h-1、(175 1± 311)pmol·mg-1·h-1、0 191± 0 0 12和 0 30 1± 0 0 17,与A组 [(0 5± 0 3) %、(2 5± 8)nmol·L-1·h-1、(385± 4 6 )pmol·mg-1·h-1、0 0 5 9± 0 0 0 5、0 131± 0 0 11]和C组 [(4 9± 2 1) %、(132±39)nmol·L-1·h-1     

哮喘豚鼠血红素氧合酶1的表达与调节

目的　探讨血红素氧合酶１（ＨＯ１） 在哮喘中的表达与作用机制。方法　７０ 只豚鼠完全随机分为７ 组,每组１０ 只,其中两组分别应用ＨＯ１ 特异性激动剂血晶素和抑制剂锡原卟啉处理豚鼠哮喘模型,另外５ 组分别为哮喘发作前、发作、自然缓解、地塞米松预防和正常对照组,应用分光光度计和放射免疫竞争分析法等,检测血及肺组织的ＨＯ１ 活性、一氧血红蛋白（ＣＯＨｂ）、环磷酸鸟苷（ｃＧＭＰ） 、血浆ＩｇＥ 水平,观察支气管肺泡灌洗液（ＢＡＬＦ） 中细胞数、肺组织病理学和ＨＯ１ 免疫组织化学染色的变化。结果　哮喘发作组和血晶素激动组的各项指标与正常对照组比较,差异均有非常显著性（ｔ＝４－７５４～１０－１８８,Ｐ＜０－０１） ,血晶素组更为显著,如肺ＨＯ１ 活性：每小时每毫克蛋白生成胆红素量为（１４４９±４２６）ｐｍｏｌ;肺ＣＯＨｂ：每毫克蛋白含（０－８３ ±０－２９） ％ ;肺ｃＧＭＰ：每毫克蛋白含（１－９６ ±０－６５）ｐｍｏｌ;血浆ＩｇＥ：（７３±２１） ｋＵ／Ｌ;ＨＯ１ 蛋白表达≥４ 级;ＢＡＬＦ细胞总数：（２１±４） ×１０８／Ｌ。地塞米松预防组和锡原卟啉抑制组除ＣＯ 含量和肺ＨＯ１ 活性略高外,余项指标与正常对照组比较差异无     

血红素氧合酶1/一氧化碳系统对球囊损伤后内膜增殖及内皮功能的影响

目的 探讨血红素氧合酶1/一氧化碳((HO-1)/CO)系统对兔颈动脉球囊损伤后内膜增殖及内皮功能的影响及其可能的作用机制.方法 家兔随机分为对照组、胆固醇组、血红素组、卟啉锌组和假手术组5组,每组10只.对照组予普通饮食,其余4组喂饲含1.5%胆固醇饲料,血红素组和卟啉锌组同时分别予氯化血红素或锌原卟啉9腹腔内注射,2周后实验组行颈总动脉球囊损伤术,术后续原喂养给药8周.结果 高胆固醇饮食血脂(总胆固醇、甘油三酯、低密度脂蛋白、氧化型低密度脂蛋白)水平显著升高(P<0.01).与对照组比较,胆固醇组颈动脉一氧化氮生成量、cNOS活性显著降低,而一氧化碳生成量、血红素氧合酶活性显著增加(P均<0.01),内膜面积和内膜/中膜面积比值为(0.586±0.090比1.381±0.180).与胆固醇组比较,氯化血红素干预显著增加血红素氧合酶活性、一氧化碳生成量,显著降低内皮素1水平,内膜面积和内膜/中膜面积比值最小(0.386±0.076比0.862±0.164;P均<0.01);锌原卟啉9显著抑制血红素氧合酶活性、一氧化碳生成量,显著增高内皮素1水平,内膜面积和内膜/中膜面积比值最大(0.734±0.096比1.843±0.212),差异均有显著性(P<0.01).结论 高胆固醇饮食加球囊损伤严重损害颈动脉NOS/NO系统,血红素氧合酶1/一氧化碳系统通过代偿和调节NOS/NO系统及降低内皮素1表达从而改善内皮功能,抑制血管损伤后内膜增殖和不良重塑.     

Induction of heme oxygenase-1 and stimulation of cGMP production by hemin in aortic tissues from hypertensive rats

Heme oxygenase (HO) and carbon monoxide (CO) have been implicated in the modulation of various cardiovascular functions including blood pressure (BP) regulation. Up-regulating the HO/CO system lowers BP in young (8-week-old) but not in adult (20-week-old) spontaneously hypertensive rats (SHRs). The mechanisms for this selective effect are largely unknown. We investigated the effects of HO-1 inducer, hemin, on the HO/CO-soluble gyanylyl cyclase (sGC)/cGMP system in the aorta of prehypertensive (4-week-old) young and adult SHRs as well as age-matched Wistar-Kyoto rats (WKYs). Reduced expressions of HO-1, HO-2, and sGC proteins associated with depressed HO activity and cGMP levels were detected in young SHRs. These deficiencies were significantly reversed by hemin treatment. Macrophage infiltration of vascular tissues was more significant in adult SHRs than adult WKYs, but invisible in young SHRs and WKYs. Hemin treatment did not alter macrophage infiltration of vascular tissues in young SHRs. The same hemin administration resulted in a significant decrease in BP (from 148.6 +/- 3.2 to 125.8 +/- 2.6 mmHg, P <.01) in young SHRs, but not in prehypertensive or adult SHRs or WKYs of all ages. The HO inhibitor zinc protoporphyrin abrogated the hemin effect in young SHRs. Aortic tissues became desensitized to YC-1, an activator sGC, in adult SHRs. Thus, in young SHRs the expression and function of the HO/CO-sGC/cGMP system were suppressed, constituting a pathogenic mechanism for the development of hypertension. In adult SHRs, the HO/CO-sGC/cGMP system appeared normal, but desensitization of the sGC/cGMP pathway caused hypertension to prevail.     

Alteration of heme-oxygenase-carbon monoxide pathway in calcified rat vascular smooth muscle cells

OBJECTIVE: The aim of the present study was to investigate the changes in heme-oxygenase (HO)-carbon monoxide (CO)-cyclic guanosine monophosphate (cGMP) pathway in clacified rat vascular smooth muscle cells (VSMCs). METHODS: Calcification of cultured rat VSMCs was induced by incubation of VSMCs with beta-glycerophosphate. Cellular calcium content, ALP activities and (45)Ca uptake were measured. HO activity, HbCO formation and content of cGMP in VSMCs were determined. Immunocytochemistry for HO-1 expression was observed. RESULTS: In comparison of control VSMCs, the cellular calcium content, ALP activity and (45)Ca uptake in calcified VSMCs were obviously increased. Immunocytochemistry showed that HO-1 expression was weak and not well distributed in calcified cells as compared to non-calcified VSMCs, but interestingly, there was stronger staining in calcified nodules than in VSMCs. Compared with VSMCs, HO-1 activity in calcified cells decreased by 42.7% [36.4 +/- 2.8 pmol (mg Pr x h)(-1) vs 63.5 x 5.3 pmol (mg Pr x h)(-1), p < 0.01], and HbCO formation decreased by 39.2% (3.38 x 0.69 micromol/mg Pr vs 5.56 +/- 0.48 micromol/mg Pr, p < 0.05). The cGMP content in calcified VSMCs was 78.1% lower than that of non-calcified VSMCs (4.3 +/- 0.51 vs 19.6 +/- 1.2 pmol/mg, p < 0.01). CONCLUSION: The results showed that HO-CO-cGMP pathway in calcified vascular cells obviously changed, which might contribute to disturbance of vascular function.     

血红素氧合酶-1和一氧化碳对兔球囊损伤后再狭窄血管的保护作用

目的 研究血红素氧合酶-1(HO-1)与一氧化碳(CO)系统对兔颈动脉球囊损伤后再狭窄血管的保护作用及其可能的机制.方法 新西兰大白兔随机分为5组:对照组、假手术组、胆固醇组、血红素组和卟啉锌组.对照组予普通饲料,其余4组喂饲含1.5%胆固醇饲料,血红素组和卟啉锌组同时分别予氯化血红素或锌原卟啉-9腹腔内注射,2周后行颈总动脉球囊损伤,术后继续原方法喂养给药8周.结果 与对照组比较,胆固醇组颈动脉一氧化氮合酶活性、一氧化氮生成量显著降低,而HO-1表达、CO生成量显著增加(均P＜0.01);与胆固醇组比较,血红素组HO-1表达、CO生成量增加,同时内皮素-1表达降低,内膜厚度和内膜增殖指数最小[分别为(442.17±59.14)μm和3.99±0.52与(281.47±21.10)μm和2.49±0.17,均P＜0.01];卟啉锌组HO-1表达、CO生成量降低,而内皮素-1表达增高,内膜厚度和内膜增殖指数最大[(698.71±58.37)um和6.17±0.52,均P＜0.01].结论 HO-1与CO系统可能通过代偿和调节一氧化氮合酶和(或)一氧化氮系统以及降低内皮素-1表达,对血管损伤后内皮功能、内膜增生和血管重塑起到保护作用,从而抑制再狭窄.

Abstract：

Objective To investigate the protective effect of heme oxygenase-1 (HO-1)/carbon monoxide (CO) system on restenosis after balloon angioplasty and relative mechanism. Methods Fifty rabbits were randomly divided into 5 groups. Control group received normal chow (Control group), the other rabbits received 1.5% cholesterol diet (Chol group and SH group) or 1.5%cholesterol diet plus hemin (Hem group) or zinc protoporphyrin Ⅸ (Znpp group) for 10 weeks. At the third week of experiment, the three experimental groups underwent balloon injury at one side common carotid artery. Results Compared with control group, arterial nitric oxide production and nitricoxide synthase activity were significantly decreased, while HO-1 expression and CO production were significantly increased (all P＜0. 01 ) in Chol group. The intima thickness and ratio of intima/media (I/M) were lower in Hem group than in Chol group [(281.47± 21.10) μm vs. (442.17 ±59.14) μm, 2.49 ± 0. 17 vs. 3.99 ± 0. 52, respectively]. While arterial HO-1 expression and CO production were increased markedly, endothelin-1 expression was distinctly reduced in Hem group group than in Chol group. Compared with Chol group, arterial HO-1 expression and CO production were decreased obviously, while endothelin-1 expression and intima thickness and ratio of intima/media [(698.71±58. 37) μm, 6.17±0. 52]were significantly increased in Znpp group (all P＜0. 01).Conclusions The HO-1/CO system plays a protective role on improving endothelium function and restraining neointimal proliferation by compensating and regulating nitricoxide synthase/nitric oxide system and lowering endothelin -1 expression so as to inhibit restenosis after balloon injury.     

Nitric oxide-mediated cytoprotection of hepatocytes from glucose deprivation-induced cytotoxicity: involvement of heme oxygenase-1

Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in heme catabolism, which leads to the generation of carbon monoxide (CO), biliverdin, and free iron. One of 3 mammalian HO isoforms, HO-1, is a stress-responsive protein and known to modulate such cellular functions as cytokine production, cell proliferation, and apoptosis to protect organs and tissues from acute injury. Although nitric oxide (NO)-mediated cytoprotective effects against cytotoxicity induced by glucose deprivation have been well recognized, the underlying mechanisms remain to be elucidated. Thus, we investigate the involvement of HO-1 in the cytoprotective effects of NO. Deprivation of glucose markedly reduced the viability of BNL CL.2 cells and primary rat hepatocytes. Pretreatment with NO donor, sodium nitroprusside (SNP), protected hepatocytes from glucose deprivation-induced cytotoxicity; zinc protoporphyrin (ZnPP) IX, an inhibitor of HO, was found to block the SNP-induced cytoprotection. SNP increased the induction of HO-1 protein as well as its activity in hepatocytes. A cytoprotective effect comparable to SNP was observed when the cells were transfected with HO-1 gene or preincubated with another HO-1 inducer, hemin. Additional experiments revealed the involvement of CO in the cytoprotective effect of SNP/HO-1 in BNL CL.2 cells. CO mediated cytoprotective effect through suppression of ERK MAPK activation. In conclusion, our results show that SNP protects hepatocytes from glucose deprivation-induced cytotoxicity through up-regulation of HO-1. Thus, HO-1 might be an important cellular target of NO donor with clinical implications for the prevention of acute liver injury in several pathological conditions.