N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对大鼠心脏成纤维细胞c-Jun氨基末端激酶通路活化的影响

目的 探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸(AcSDKP)对血小板源生长因子诱导的大鼠心脏戍纤维细胞增殖及胶原合成以及c-Jun氨基末端激酶表达的影响.方法 选用新生Wistar大鼠心脏成纤维细胞作为实验研究材料,MTT法检测心脏成纤维细胞代谢活性的改变,免疫细胞化学法检测Ⅰ型、Ⅲ型胶原表达的改变,Western Blotting检测大鼠心脏成纤维细胞中磷酸化JNK(p-JNK)和JNK蛋白及Ⅰ型、Ⅲ型胶原蛋白的表达.结果 10μg/L血小板源生长因子刺激下,代表大鼠心脏成纤维细胞代谢活性的OD值增加,Ⅰ型、Ⅲ型胶原表达增强,表明血小板源生长因子刺激了心脏成纤维细胞增殖,促进了胶原的合成.同时p-JNK蛋白表达增高,而JNK蛋白表达无明显改变.10-9mol/L AcSDKP能够抑制血小板源生长因子诱导的大鼠心脏成纤维细胞代谢活性,同时抑制了Ⅰ型、皿型胶原及p-JNK蛋白的表达,而JNK蛋白表达无明显改变.结论 AcSDKP能够通过阻断血小板源生长因子介导的JNK通路激活进而抑制大鼠心脏成纤维细胞增殖和胶原蛋白表达.     

细胞外信号调节激酶1/2在抗纤维化短肽AcSDKP调节大鼠心脏成纤维细胞增殖和胶原表达中的作用

目的 探讨AcSDKP是否通过阻断细胞外信号调节激酶1/2(ERK1/2)途径调节血小板源性生长因子(PDGF)诱导的大鼠心脏成纤维细胞增殖和胶原蛋白表达. 方法 CCK-8法检测心脏成纤维细胞代谢活性.流式细胞仪法检测细胞周期.免疫细胞化学法、Western blot法检测Ⅰ、Ⅲ型胶原蛋白表达.Western blot法检测ERK1/2及磷酸化-ERK1/2蛋白表达. 结果 10-9mol/L AcSDKP能够抑制PDGF诱导的大鼠心脏成纤维细胞代谢活性,减少了细胞由G1期向S期的转化,细胞增殖指数下降.抑制了Ⅰ、Ⅲ型胶原及磷酸化-ERK1/2蛋白的表达,而ERK1/2蛋白表达无明显改变. 结论 AcSDKP能够通过阻断PDGF介导的ERK1/2通路的激活进而抑制大鼠心脏成纤维细胞增殖和胶原蛋白表达.     

N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对转化生长因子β1介导的心肌成纤维细胞增殖的抑制作用

目的:探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰一脯氨酸(AcSDKP)对转化生长因子β_1(TGF-β_1)介导的大鼠心肌成纤维细胞增殖的调节作用。方法:采用差速贴壁法获取新生大鼠心肌成纤维细胞;采用MTT法(以OD值反映细胞活性)和~3H-TdR掺入法(以CPM值反映DNA合成)检测心肌成纤维细胞的增殖,采用免疫细胞化学染色法检测心肌成纤维细胞的增殖细胞核抗原(PCNA)的表达。结果:TGF-β_1在1～10ng/ml浓度范围内刺激心肌成纤维细胞增殖较0.4%胎牛血清培养的心肌成纤维细胞有显著性差异(P<0.05)。当加入AcSDKP时,AcSDKP(在10~(-10)～10~(-8)mol/L浓度范围内)随着其浓度的增加,OD值(MTT法)、CPM值(~3H-TdR掺入法)逐渐下降,其相应抑制率逐渐增高,差异均有显著性(P<0.05)。并在10~(-9)mol/L浓度时其抑制作用最佳。结论:AcSDKP对TGF-β_1介导的心肌成纤维细胞增殖有明显抑制作用,这可能与其抗心肌纤维化的作用相关。     

AcSDKP对大鼠心脏成纤维细胞MMP-1、TIMP-1及Ⅰ、Ⅲ型胶原表达的影响

目的探讨N-乙酰基—丝氨酰—天门冬酰—赖氨酰—脯氨酸（AcSDKP）抗心肌纤维化的可能机制。方法将大鼠心脏成纤维细胞随机分为三组,对照组予0.4%胎牛血清的DMEM;转化生长因子（TGF）-β1组在0.4%胎牛血清的DMEM中加入终质量浓度为5 ng/ml的TGF-β1;AcSDKP组在5 ng/ml的TGF-β1诱导刺激同时加入终质量浓度为10-9mol/L的AcSDKP。Western blot法检测MMP-1、TIMP-1、Ⅰ和Ⅲ型胶原表达。结果 TGF-β1可使MMP-1表达下降,TIMP-1表达升高,MMP-1/TIMP-1值下降;AcSDKP抑制TGF-β1对MMP-1的作用,使MMP-1表达增加,但对TIMP-1表达无明显影响,MMP-1/TIMP-1值增加。同时AcSDKP减弱由TGF-β1诱导的Ⅰ和Ⅲ型胶原表达,并降低Ⅰ/Ⅲ型值。结论 AcSDKP抗纤维化的作用机制可能是调节胶原合成/降解代谢的平衡,加速细胞外基质降解,同时抑制Ⅰ和Ⅲ型胶原生成。     

抗器官纤维化短肽——AcSDKP对心脏纤维化的作用及其研究进展

N-乙酰基-丝氨酰-天门冬氨酰-赖氨酰-脯氨酸(AcSDKP)是一种具有抗器官纤维化作用的由四个氨基酸构成的短肽.正常生理状态下,存在于人的血浆和淋巴系统内.近年研究发现AcSDKP能够抑制诸多器官如心、肺、肾、肝的纤维化.其中可以抑制器官内的靶细胞(如心脏成纤维细胞、肺成纤维细胞、肾小球系膜细胞和肝星状细胞)的增殖和胶原蛋白的合成或表达,通过信号转导系统的调节抑制靶器官内胶原的沉积,减轻致病因素导致的器官纤维化的程度.     

瑞舒伐他汀对TGF-β1诱导的新生大鼠心脏成纤维细胞增殖及其胶原合成与分泌的作用和机制

目的 探讨瑞舒伐他汀对转化生长因子β1 (TGF-β1)诱导的新生大鼠心脏成纤维细胞增殖及其胶原合成与分泌的作用和可能机制.方法 分离、培养新生SD大鼠的心脏成纤维细胞,采用CCK-8比色法测定细胞数目.用RT-PCR检测Ⅰ型胶原蛋白和Ⅲ型胶原蛋白mRNA的表达,用ELISA测定Ⅰ型胶原蛋白和Ⅲ型胶原蛋白含量,用Western blot检测心脏成纤维细胞Akt的蛋白表达.结果 CCK-8比色法显示,瑞舒伐他汀能抑制TGF-β1引起的心脏成纤维细胞增殖;RT-PCR结果显示,瑞舒伐他汀能抑制TGF-β1诱导的Ⅰ型胶原蛋白和Ⅲ型胶原蛋白mRNA的表达;ELISA结果显示,瑞舒伐他汀能抑制TGF-β1诱导的Ⅰ型胶原蛋白和Ⅲ型胶原蛋白分泌;Westernblot结果显示,瑞舒伐他汀能抑制TGF-β1诱导的Akt蛋白表达.结论 瑞舒伐他汀可能通过抑制TGF-β1诱导的新生大鼠心脏成纤维细胞增殖、Ⅰ型和Ⅲ型胶原蛋白的合成与分泌来抑制TGF-β1诱导的心脏纤维化,其分子机制可能与抑制Akt信号通路有关.     

松弛素对血管紧张素Ⅱ诱导的大鼠血管外膜成纤维细胞胶原水平的影响

目的:探讨松弛素(RLX)对血管紧张素(Ang)Ⅱ诱导的大鼠血管外膜成纤维细胞胶原水平的影响及机制。方法:体外培养大鼠主动脉外膜成纤维细胞,随机分为对照组、AngⅡ组(10-6 mmol/L),RLX组(100μg/L)及AngⅡ+RLX组。采用波形蛋白染色法鉴定血管外膜成纤维细胞,用RT-PCR检测Ⅰ、Ⅲ型胶原蛋白mRNA表达,用Western blot印迹法检测基质金属蛋白酶(MMP)-2、MMP-9及转化生长因子(TGF)-β1蛋白的表达。结果:AngⅡ可显著增加培养液上清中Ⅰ、Ⅲ型胶原蛋白含量及TGF-β1蛋白表达,而RLX明显抑制AngⅡ的上述作用;AngⅡ可显著下调细胞内MMP-2和MMP-9的蛋白表达,而RLX明显抑制AngⅡ的上述作用(均P<0.05)。结论:AngⅡ可刺激血管外膜成纤维细胞胶原合成增加,而RLX通过上调MMP-2、MMP-9表达和下调TGF-β1表达,抑制AngⅡ刺激的Ⅰ、Ⅲ型胶原蛋白生成,从而发挥抗血管纤维化作用。     

血小板源生长因子对动脉平滑肌细胞增殖,Ⅰ、Ⅲ型前胶原信使核糖核酸的表达及胶原蛋白合成的调节作用

目的：研究血小板源生长因子（ＰＤＧＦ）对培养的人主动脉平滑肌细胞增殖、胶原蛋白合成、分泌及Ⅰ、Ⅲ型前胶原信使核糖核酸（ｍＲＮＡ）表达和转移生长因子βｍＲＮＡ表达的调节作用。方法：氚胸腺嘧啶脱氧核苷（３ＨＴｄＲ），氚脯氨酸参入及Ｎｏｒｔｈｅｒｎ杂交分析。３ＨＴｄＲ，氚脯氨酸参入的比较采用ｔ检验。结果：ＰＤＧＦ能促进人主动脉平滑肌细胞脱氧核糖核酸（ＤＮＡ）合成和胶原蛋白合成、分泌；ＰＤＧＦ能上调Ⅰ、Ⅲ型前胶原ｍＲＮＡ表达和转移生长因子βｍＲＮＡ表达。结论：血小板源生长因子能通过上调Ⅰ、Ⅲ型前胶原ｍＲＮＡ表达和转移生长因子βｍＲＮＡ表达促进平滑肌细胞胶原蛋白的合成、分泌。     

敲低Tribbles同源蛋白3抑制血管紧张素Ⅱ诱导的心肌成纤维细胞增殖

目的研究敲低Tribbles同源蛋白(TRIB)3对血管紧张素(Ang)Ⅱ诱导的心肌成纤维细胞增殖的影响。方法用AngⅡ处理心肌成纤维细胞,实时荧光定量-聚合酶链反应(qRT-PCR)和Western印迹法检测细胞中TRIB3表达情况。心肌成纤维细胞转染TRIB3 siRNA慢病毒载体,经AngⅡ处理后,qRT-PCR和Western印迹检测干扰效率。噻唑蓝(MTT)检测细胞增殖,羟脯氨酸法检测胶原合成,Western印迹法检测细胞中Ⅰ型胶原(COLL)Ⅰ、COLLⅡ和基质金属蛋白酶(MMP)-2蛋白表达,硝酸还原法检测培养液中一氧化氮(NO)含量,酶联免疫吸附试验(ELISA)检测培养液中诱导型一氧化氮合成酶(iNOS)活性。结果 AngⅡ处理后的心肌成纤维细胞中的TRIB3表达水平升高(P0.01)。TRIB3 siRNA慢病毒载体可明显下调AngⅡ条件下心肌成纤维细胞中TRIB3的表达水平(P0.05)。AngⅡ处理后的心肌成纤维细胞增殖能力升高(P0.05),细胞胶原合成增多(P0.05),细胞中COLLⅠ、COLLⅡ蛋白水平升高(P0.05),MMP-2水平降低(P0.05),培养液中NO含量降低(P0.05),iNOS活性降低(P0.05)。下调TRIB3能够降低AngⅡ条件下心肌成纤维细胞增殖能力(P0.05),减少细胞胶原合成(P0.05),降低细胞中COLLⅠ、COLLⅡ蛋白表达(P0.05),促进细胞中MMP-2蛋白表达(P0.05),促进细胞分泌NO(P0.05),提高细胞iNOS活性(P0.05)。结论敲低TRIB3能够抑制AngⅡ诱导的心肌成纤维细胞增殖,减少胶原合成,促进细胞分泌NO。     

血管紧张素(1-7)对血管紧张素Ⅱ诱导心脏成纤维细胞增殖和胶原合成的影响

目的探讨血管紧张素(1-7)对血管紧张素Ⅱ诱导心脏成纤维细胞增殖和胶原合成的影响。方法分离培养SD仔鼠心脏成纤维细胞,四氮唑盐比色法检测细胞增殖,流式细胞分析技术测定细胞周期,逆转录—聚合酶链式反应测定心脏成纤维细胞Ⅰ、Ⅲ型胶原mRNA的表达。结果①1.0μmol/L血管紧张素Ⅱ作用24h,心脏成纤维细胞的四氮唑蓝比色分析法吸光度值(0.24±0.01)较无血清对照组(0.14±0.01)明显增加(P<0.01);0.001~1.0μmol/L血管紧张素(1-7)和1.0μmol/L血管紧张素Ⅱ共同干预后吸光度值逐渐降低,分别为0.20±0.01、0.19±0.01、0.13±0.01、0.16±0.03,均显著低于血管紧张素Ⅱ组(P<0.01)。②血管紧张素Ⅱ组心脏成纤维细胞的S期百分率(14.0%±0.9%)和增殖指数(23.4±1.8)较对照组(5.4%±0.7%和10.8±2.4)明显增高(P<0.01);0.1μmol/L血管紧张素(1-7)干预后S期百分率(8.5%±0.7%)和增殖指数(16.2±2.0)较血管紧张素Ⅱ组降低(P<0.01)。③血管紧张素Ⅱ刺激后心脏成纤维细胞的Ⅰ、Ⅲ型胶原mRNA表达水平分别为较对照组明显增高(P<0.01);给予0.001~1.0μmol/L血管紧张素(1-7)和1.0μmol/L血管紧张素Ⅱ共同干预后,胶原表达水平浓度依赖性的下降,均显著低于血管紧张素Ⅱ组(P<0.05)。结论血管紧张素(1-7)具有抑制血管紧张素Ⅱ浓度增加引起的心脏成纤维细胞增殖和胶原合成的作用。     

肾上腺髓质素对血管紧张素Ⅱ促血管外膜成纤维细胞胶原生成作用的影响

目的探讨肾上腺髓质素（ADM）对血管紧张素Ⅱ（AngⅡ）诱导的血管外膜成纤维细胞胶原生成的影响及机制。方法体外培养大鼠主动脉外膜成纤维细胞,通过放射免疫法测定培养上清中ADM含量,采用酶联免疫吸附法（ELISA）测定培养上清中Ⅰ、Ⅲ型胶原蛋白含量,用逆转录一聚合酶链反应（RT—PCR）及Western印迹法检测转化生长因子β1（TGFβ1）和基质金属蛋白酶-2（MMP-2）mRNA及蛋白的表达。结果AngII呈剂量依赖性地刺激血管外膜成纤维细胞分泌ADM,在AngⅡ（10^-6mol／L）刺激前30min加入氯沙坦或（和）PD123319,氯沙坦（10^-5mol／L）可明显降低AngⅡ刺激的ADM分泌,其抑制率为45％（P〈0．01）,而PD123319（10mmol／L）作用后抑制率仅为3％（P〉0．05）,氯沙坦＋PD123319组与单独氯沙坦组相比差异无统计学意义（P〉0．05）;AngⅡ显著增加培养上清中Ⅰ、Ⅲ型胶原蛋白含量,ADM呈剂量依赖地抑制AngⅡ上述作用,其中ADM（10“mol／L）组中I、Ⅲ型胶原合成分别抑制了30％和31％（P〈0．01）,ADM（10^-7mol／L）组则分别抑制了43％和42％（P〈0．01）。ADM受体拈抗剂ADM22-52可增强AngII上述作用,Ⅰ、Ⅲ型胶原合成分别增加了38％和43％（P〈0．01）;ADM呈剂量依赖性抑制AngⅡ刺激的TGFβ1mRNA及蛋白表达,其中ADM（10^-8mol／L）组中TGFβ1mRNA及蛋白表达分别抑制了55％和45％（P〈0．01）,ADM（10^-7mol／L）组则分别抑制了70％和59％（P〈0．01）;AngⅡ明显下调细胞内MMP-2mRNA及蛋白表达,ADM呈剂量依赖性抑制上述作用,其中10^-8mol／LADM组细胞内MMP-2mRNA及蛋白表达分别增加了1．0和0．9倍。结论AngⅡ可刺激血管外膜成纤维细胞释放ADM,而自分泌旁分泌的ADM可能通过下调细胞内TGFN表达和上调MMP-2表达,抑制AngⅡ刺激的Ⅰ、Ⅲ型胶原蛋白生成,从而发挥有效的抗血管重构作用。     

Beneficial regulation of type I collagen and matrixmetalloproteinase-1 expression by estrogen, progesterone, and its combination in skin fibroblasts.

There is impaired wound healing and loss of type I collagen in skin aging, which can be improved by topical estrogen in vivo. The goal of this study was to determine the effects of estrogen, and progesterone and a combination of estrogen and progesterone as well, on the proliferation and the expression of type I collagen and matrixmetalloprotienase-1 (MMP-1, degrades collagen) in dermal fibroblasts (cells that synthesize collagen and MMP-1) in-vitro. Estrogen, progesterone, and its combination similarly and significantly inhibited cell proliferation and MMP-1 protein levels, and simultaneously stimulated type I collagen expression in the fibroblasts, indicating beneficial modulation.     

The Effect of Ras Inhibition on the Proliferation, Apoptosis and Matrix Metalloproteases Activity in Rat Hepatic Stellate Cells

In vivo inhibition of Ras by its antagonist farnesylthiosalicylic acid (FTS) prevents and reverses liver fibrosis in a rat model. In this study we showed the in vitro effects of Ras inhibition in a rat hepatic stellate cell line, HSC-T6. The IC₅₀ of FTS that inhibited PDGF-induced proliferation was 15 μM. FTS, by itself or in combination with PDGF, induced a three- to fivefold increase in the number of apoptotic stellate cells but did not induce apoptosis in cells cultured with TGFβ1. We observed increased activity of MMP-9 and MMP-2 induced by FTS in combination with PDGF or TGFβ. FTS, alone or in the presence of PDGF and TGFβ, reduced collagen I mRNA expression. In conclusion, the in vivo amelioration of liver fibrosis by FTS may be explained by its ability to inhibit hepatic stellate cell proliferation, induce apoptosis and MMP-2 and MMP-9 activity, and decrease collagen I expression.     

Collagen I and III mRNA gene expression and cell growth potential of skin fibroblasts in patients with essential hypertension

OBJECTIVES : Despite the claimed disregulation of extracellular matrix synthesis and the increased proliferation rate of different cell types in experimental models of hypertension, very few data are available on collagen synthesis and the proliferation rate of fibroblasts in essential hypertensive patients. DESIGN : We measured collagen I, collagen III, histone H3 mRNA gene expression, collagen protein concentration and thymidine incorporation in fibroblasts from 17 essential hypertensive patients (EH) and 13 healthy normotensive control subjects (NC). METHODS : A Northern blot analysis was performed on fibroblasts in culture obtained from skin biopsies. Collagen protein concentration and DNA synthesis were measured by means of incorporation of tritiated proline and tritiated thymidine, respectively. RESULTS : In cultivated fibroblasts from hypertensives, the expression of collagen III mRNA after addition of fetal calf serum was significantly increased in comparison with that of normotensive-derived cells. After addition of fetal calf serum, collagen protein was statistically increased in cultures from EH patients as compared to NC. In hypertensives, the expression of histone H3 mRNA as well as tritiated thymidine incorporation were both increased as compared to normotensives. CONCLUSIONS : Our data suggest that cultivated fibroblasts from essential hypertensive patients are characterized by an increased expression of type III collagen mRNA and collagen protein synthesis in response to fetal serum, as compared to normotensive-derived cells. Cells from hypertensives are characterized by an increased rate of proliferation after addition of fetal serum, as ascertained by increased thymidine incorporation and increased histone H3 mRNA gene expression, as compared to normotensive-derived cells. This phenotype could be genetically determined and may have an important role in the pathogenesis of essential hypertension.     

Effects of synthetic serine protease inhibitors on proliferation and collagen synthesis of human pancreatic periacinar fibroblast-like cells

Protease inhibitors are currently used as therapeutic agents for chronic pancreatitis in Japan. We previously reported that human pancreatic periacinar fibroblast-like cells (hPFCs) could be cultured from isolated pancreatic acini, and those are thought to play a crucial role in pancreatic fibrosis correlating with platelet-derived growth factor (PDGF) and transforming growth factor beta1 (TGF-beta1) (Pancreas 1997;14: 373-82). The present study was designed to examine the effects of synthetic serine protease inhibitors (FOY-007 and FOY-305) on proliferation and collagen synthesis of hPFCs under cytokine stimulation. The cell proliferation and collagen synthesis were evaluated using assays of [3H]-thymidine incorporation and procollagen type I c-terminal peptide (PIP), and [14C]-proline incorporation to de novo synthesized collagen, respectively. The cell proliferation stimulated by PDGF was inhibited by the application of FOY-007 dose dependently (1-100 microM) and FOY-305 at 100 microM. FOY-007 attenuated the collagen synthesis and PIP production stimulated by TGF-beta1 dose dependently, but FOY-305 inhibited only PIP production. Both protease inhibitors demonstrated no effect on the proliferation and collagen synthesis of hPFCs when they were not stimulated by PDGF or TGF-beta1. Thus, serine protease inhibitors act on hPFCs to diminish the effects of PDGF on proliferation and the effects of TGF-beta1 on collagen synthesis.     

黏着斑激酶相关非激酶对CFSC细胞基质金属蛋白酶-2及其抑制因子mRNA表达的影响

目的 探讨黏着斑激酶相关非激酶(FRNK)对纤维连接蛋白刺激的肝星状细胞CFSC胶原代谢的影响及其分子机制. 方法用体外细胞培养技术,脂质体介导法进行FRNK质粒瞬时转染;采用Western blot方法测定FRNK蛋白表达,鉴定转染效果;用3H-Pro掺入技术测定CFSCI型胶原的合成;用RT-PCR方法测定FRNK转染前后基质金属蛋白酶2(MMP-2)及其抑制因子(TIMP-2)基因在CFSC中表达的变化情况. 结果 FRNK质粒成功转染CFSC,Ⅰ型胶原合成下降;MMP-2基因表达上升,TIMP-2基因表达下降,MMP 2/TIMP-2比值明显上升.结论 外源性FRNK在CFSC内大量表达后,CFSC胶原表达减少;FRNK可能通过调节MMP-2/TIMP-2比值来促进CFSC的胶原降解.     

Transforming growth factor-β regulates growth as well as collagen and fibronectin synthesis of human marrow fibroblasts

Three growth factors present in platelets, namely platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta) and epidermal growth factor (EGF), have been implicated in the pathogenesis of bone marrow fibrosis frequently associated with myeloproliferative disorders. In this study, regulation of the proliferation, as well as collagen and fibronectin synthesis from marrow fibroblasts by TGF-beta was investigated. TGF-beta alone at high plating density stimulated the proliferation of cells at low concentrations, but rather showed inhibition at high concentrations in both MPD patients and control subjects. In the presence of PDGF, which has been confirmed to be a main growth factor for marrow fibroblasts, low concentration of TGF-beta inhibited the proliferation at low cell density, but there was no inhibition at high cell density. The synthesis of both type I and type III procollagen was enhanced by high concentrations of TGF-beta in both MPD patients and control subjects, while PDGF or EGF showed no effect. The fibronectin synthesis was also enhanced by TGF-beta, but not by PDGF or EGF. These results suggest that growth and stromal protein synthesis of fibroblasts causing marrow fibrosis are regulated by TGF-beta as well as PDGF and EGF, when these factors are released or leaked from platelets or megakaryocytes into marrow environment in MPD patients.     

Involvement of reactive oxygen species in angiotensin II-induced endothelin-1 gene expression in rat cardiac fibroblasts

OBJECTIVES: The aim of this study was to investigate the effects of angiotensin II (Ang II) on fibroblast proliferation and endothelin-1 (ET-1) gene induction, focusing especially on reactive oxygen species (ROS)-mediated signaling in cardiac fibroblasts. BACKGROUND: Angiotensin II increases ET-1 expression, which plays an important role in Ang II-induced fibroblast proliferation. Angiotensin II also stimulates ROS generation in cardiac fibroblasts. However, whether ROS are involved in Ang II-induced proliferation and ET-1 expression remains unknown. METHODS: Cultured neonatal rat cardiac fibroblasts were stimulated with Ang II, and then [(3)H]thymidine incorporation and the ET-1 gene expression were examined. We also examined the effects of antioxidants on Ang II-induced proliferation and mitogen-activated protein kinase (MAPK) phosphorylation to elucidate the redox-sensitive pathway in fibroblast proliferation and ET-1 gene expression. RESULTS: Both AT(1) receptor antagonist (losartan) and ET(A) receptor antagonist (BQ485) inhibited Ang II-increased DNA synthesis. Endothelin-1 gene was induced with Ang II as revealed by Northern blotting and promoter activity assay. Angiotensin II increased intracellular ROS levels, which were inhibited with losartan and antioxidants. Antioxidants further suppressed Ang II-induced ET-1 gene expression, DNA synthesis, and MAPK phosphorylation. PD98059, but not SB203580, fully inhibited Ang II-induced ET-1 expression. Truncation and mutational analysis of the ET-1 gene promoter showed that AP-1 binding site was an important cis-element in Ang II-induced ET-1 gene expression. CONCLUSIONS: Our data suggest that ROS are involved in Ang II-induced proliferation and ET-1 gene expression. Our findings imply that the combination of AT(I) and ET(A) receptor antagonists plus antioxidants may be beneficial in preventing the formation of excessive cardiac fibrosis.