沉默结缔组织生长因子对鼠转化生长因子β/Smads信号的影响

目的 研究小干扰RNA(siRNA)沉默结缔组织生长因子(CTGF)对大鼠转化生长因子(TGF)β/Smads信号通路的影响.方法 将化学合成CTGF siRNA转染肝星状细胞(HSC)T6和经门静脉注入CCl4诱导6周的肝纤维化大鼠,设空白及随机siRNA对照,抽提HSC T6及大鼠肝组织总RNA和蛋白质,应用Western blot和RT-PCR检测HSC T6及肝组织CTGF及TGF β1,Smad2、3、7蛋白质和基因表达. 结果与空白对照组相比,siRNA能显著下调HSC T6 CTGF蛋白表达,以48 h最明显,CTGF蛋白表达下调94%±4%(t=46.196,P<0.01),而TGF β1、Smad2,3,7 mRNA表达差异无统计学意义;模型组及对照siRNA组,CCl4诱导的大鼠肝组织CTGF和TGF β1蛋白表达明显上调,与模型组相比,CTGF siRNA组大鼠肝组织CTGF及TGF β1蛋白表达分别下调95%±2%(F=21.234,P<0.01)和74%±8%(F=13.464,P<0.05),但Smad2和Smad7蛋白表达无明显改变. 结论沉默CTGF基因表达对大鼠肝TGF β/Smads信号具有阻抑作用.     

Glomerular expression of thrombospondin-1, transforming growth factor beta and connective tissue growth factor at different stages of diabetic nephropathy and their interdependent roles in mesangial response to diabetic stimuli

Aims/hypothesis We quantified the glomerular expression of thrombospondin-1 (THBS1, also known as TSP-1), transforming growth factor beta 1 (TGFB1, also known as TGF-β1) and connective tissue growth factor (CTGF) at each stage of diabetic nephropathy. We also examined the roles of THBS1 and CTGF in mediating high-glucose- and glycated-albumin-induced synthesis of the matrix protein, fibronectin, by mesangial cells. Methods THBS1, latent and active TGFB1, and CTGF, were detected by immunohistochemistry and in situ hybridisation in biopsies from 19 insulin-dependent diabetic patients with incipient, manifest and advanced diabetic nephropathy, and in 11 control kidneys. Findings were quantified by image analysis. Human mesangial cells were cultured with normal or high glucose, albumin or glycated albumin (Amadori product), +/−THBS1 or CTGF antisense oligonucleotides, or with peptide W, an inhibitor of TGFB1 bioactivation by THBS1. Proteins were measured by western blot analysis or ELISA. Results In glomeruli of normal kidneys, mRNA and protein levels for THBS1, latent-TGFB1 and CTGF were low. They were increased in the incipient stage of diabetic nephropathy, predominantly in mesangial areas, with further increases at later stages of the disease. Little or no active TGFB1 immunostaining was detected prior to manifest diabetic nephropathy. In contrast to high-glucose conditions, increases in fibronectin synthesis that were stimulated by glycated albumin were not dependent on THBS1 activation of latent TGFB1. However, increased fibronectin synthesis in both conditions required CTGF. Conclusions/interpretation Increased glomerular expression of all three factors occurs from the earliest stage of diabetic nephropathy. In contrast to THBS1, CTGF is required for mesangial synthesis of fibronectin stimulated by high glucose or glycated albumin, and is thus a potential therapeutic target. N. A. Wahab and L. Schaefer made an equal contribution to the work reported in this paper     

Type beta transforming growth factor: a bifunctional regulator of cellular growth.

Type beta transforming growth factor (TGF-beta) is a two-chain polypeptide of 25,000 daltons isolated from many tissues, including bovine kidney, human placenta, and human platelets. It has been characterized by its ability to stimulate reversible transformation of nonneoplastic murine fibroblasts, as measured by the formation of colonies of these cells in soft agar (ED50 = 4 pM TGF-beta for NRK fibroblasts). We now show that the response of cells to TGF-beta is bifunctional, in that TGF-beta inhibits the anchorage-dependent growth of NRK fibroblasts and of human tumor cells by increasing cell cycle time. Moreover, the anchorage-independent growth of many human melanoma, lung carcinoma, and breast carcinoma cell lines is inhibited by TGF-beta at concentrations in the same range as those that stimulate colony formation of NRK fibroblasts (average ED50 = 10-30 pM TGF-beta for inhibition). Whereas epidermal growth factor and TGF-beta synergize to induce anchorage-independent growth of NRK fibroblasts, their effects on the growth of A-549 human lung carcinoma cells are antagonistic. The bifunctional response of cells to TGF-beta is further demonstrated in Fischer rat 3T3 fibroblasts transfected with a cellular myc gene. In these cells TGF-beta synergizes with platelet-derived growth factor to stimulate colony formation but inhibits the colony formation induced by epidermal growth factor. The data indicate that the effects of TGF-beta on cells are not a function of the peptide itself, but rather of the total set of growth factors and their receptors that is operant in the cell at a given time.     

Platelet-derived growth factor, transforming growth factor-beta, and connective tissue growth factor in a porcine bronchial model of obliterative bronchiolitis

The expression of platelet-derived growth factor (PDGF), transforming growth factor (TGF)-beta, and connective tissue growth factor (CTGF) and the effect of imatinib, an agent inhibiting PDGF receptors, were assessed in a porcine bronchial transplantation model of obliterative bronchiolitis (OB). Up-regulation of PDGF-A, PDGF receptors alpha and beta, and TGF-beta expression occurred in allografts, whereas PDGF-B and CTGF expression was similar in allo- and autografts. Imatinib modified the inflammatory responses and expression patterns of PDGF-A and PDGF receptors. This study further confirms PDGF and TGF-beta as mediators of OB and supports the concept of the importance of the pathways signaled through PDGF receptors in post-transplant OB.     

转化生长因子β1和结缔组织生长因子在肝纤维化中的表达

目的:观察肝纤维化不同阶段转化生长因子β1 (TGF-β1)和结缔组织生长因子(CTGF)在肝组织内表达的相关性．方法:41例行肝组织活检慢性病毒性肝炎患者,免疫组织化学检测TGF-β1和CTGF,并用多媒体彩色图像分析仪对上述二指标进行图像分析定量．结果:按肝纤维化分组,除S1,S2期无统计学差别意义外,TGF-β1和CTGF均随纤维化分期加重而表达增加(F=49．56,23．01,P<0．05)．按炎症活动度分组G1,G2,G3,G4组间TGF-β1两两比较无显著性差异．G1,G2,G3组CTGF两两比较无显著性差异,而G4组则有统计学意义．肝组织中TGF-β1,与CTGF呈正相关(r=0．855, P<0．05)．TGF-B1和CTGF与血清PCⅢ,LN, HA,ⅣC均呈正相关(TGF-β1:r=0．744,0．815, 0．756,0．741,P<0．05;r=0．663,0．690,0．686, 0．640．P<0．05)．结论:肝脏TGF-β1和CTGF表达水平与肝组织纤维化程度密切相关,在早期肝硬化阶段CTGF表达更可靠．     

转化生长因子-β刺激人近端肾小管上皮细胞结缔组织生长因子的表达

目的:探讨转化生长因子-β(TGF-β)对人近端肾小管上皮细胞结缔组织生长因子(CTGF)表达的影响。方法:应用逆转录-聚合酶链反应(RTP-CR)和蛋白印迹技术,观察TGF-β1对人近端肾小管上皮细胞(HK-2)α平滑肌肌动蛋白(α-SMA)和CTGFmRNA及其蛋白质表达的影响,同时观察肾小管上皮细胞形态改变。结果:HK2细胞有基础量的CTGFmRNA和蛋白质分子表达,在TGF-β1刺激下,其表达量显著增加,经不同浓度TGF-β1干预24h后,CTGFmRNA表达量明显升高,且呈剂量依赖性。1ng/mlTGF-β1刺激时,CTGFmRNA表达量开始显著增加,5ng/ml时达到高峰,10ng/ml时略有下降,CTGFmRNA表达量分别为对照组的2.40倍,3.34倍和2.73倍(P<0.05)。CTGFmRNA表达量呈时间依赖效应。TGF-β1(5ng/ml)干预30min后,CTGFmRNA表达量开始呈现增加趋势,为对照组的1.48倍(P>0.05),2h后出现显著差异,为对照组的2.14倍(P<0.05);CTGFmRNA表达量在24h达到高峰,持续至36h,分别为对照组的3.19倍和2.75倍(P<0.005);0.5ng/mlTGF-β1刺激时,CTGF蛋白表达量略有增加,5ng/ml时达到高峰,10ng/ml时略有下降。在TGF-β1(5ng/ml)干预下,HK2细胞由立方形铺路石样逐渐转变为长梭形长条样,免疫荧光检测见梭形细胞胞浆中有大量αSMA表达。大部分细胞转分化的时间(72h)明显晚于CTGFmRNA     

转化生长因子-β1对大鼠脑膜间皮细胞结缔组织因子表达的影响

目的 观察转化生长因子-β1（TGF-β1）对大鼠软脑膜间皮细胞（RLMCs）结缔组织生长因子（ CTCF）表达的影响.方法 体外培养RLMCs,并将其分为4组：（1）0组（正常对照组）：用无血清培养基（FSM）培养细胞;（2）1组：用含TGF-β11 ng/ml培养细胞;（3）2组：用含TGF-β1 2 ng/ml培养细胞;（4）3组：用含TGF-β14 ng/ml培养细胞;各组分别在TCF-β1刺激6、12及24 b后,采用逆转录-聚合酶链反应（RT-PCR）方法测定CTCF mRNA水平;蛋白免疫印迹（Westem blot）测定CTCF蛋白表达.数据以平均值±标准差（-χ±s）表示,各个浓度点组间比较采用单因素方差分析（One-way ANOVA）,两两比较采用最小显著法（LSD）检验,以P〈0.05有统计学意义.结果 在6、12及24 h分别以TCF-β1 1ng/mL、2 ng/mL、4 ng/mL处理,CTGF mRNA表达水平与对照组比较,差异有显著性（F6h=46.549、F12h= 287.098、F24h=109.202,P均〈0.001）,呈剂量依赖性,以TGF-β1处理12 h组CTGF mRNA表达差异明显.western blotting：正常对照组RLMCs细胞和不同浓度的TGF-β1刺激后均表达CTGF蛋白,在TGF-β1刺激6、12及24 h后,各组均随着浓度的增加而增加,差异有显著性（F6h= 52.988、F12h= 95.331、F24h=157.107,P均〈0.001）,呈剂量依赖性,以TGF-β1处理6h组CTGF蛋白表达差异明显.结论 TGF-β1能诱导RLMCs中CTGF通路激活.TGF-β1刺激RLMCs中CTGF mRNA和蛋白的表达,而且随浓度增加而显著.CTGF可能作为神经系统疾病中抑制脑膜纤维化的靶点而进一步研究.     

Androgens and transforming growth factor beta modulate the growth response to epidermal growth factor in human prostatic tumor cells (LNCaP)

Treatment of LNCaP human prostatic cancer cells with 0.1 nM of the synthetic androgen, R1881, resulted in a three-fold stimulation of growth in 6 days. Of several growth factors tested (epidermal growth factor (EGF), platelet-derived growth factor, insulin-like growth factor, and insulin) only EGF (1 ng/ml) stimulated cell growth (two-fold). This stimulatory effect of EGF was inhibited for approximately 70% by 0.02 ng transforming growth factor beta (TGF beta)/ml. EGF (1 ng/ml) acted synergistically with R1881 (0.1 nM) on LNCaP cells to induce cell proliferation (seven-fold increase in cell growth). The synergistic effect of androgen and EGF was inhibited by TGF beta (0.05 ng/ml). In conclusion: human prostatic LNCaP cells are sensitive to EGF. Androgen increases and TGF beta decreases the growth response to EGF. This effect of TGF beta on an androgen-responsive system has not been observed before.     

Morphologic and mitogenic responses of rabbit synovial fibroblasts to transforming growth factor beta require transforming growth factor alpha or epidermal growth factor

We tested the hypothesis that normal synovial fibroblasts might proliferate in response to transforming growth factors (TGFs), peptides that are extracted with acid-ethanol from bovine kidney or salivary gland and that cause anchorage-independent growth of normal cells. A 72-hour exposure of confluent monolayers of rabbit synovial fibroblasts in 10% fetal calf serum to partially purified TGF-beta in the presence of TGF-alpha gave a 2- to 5-fold increase in incorporation of 3H-thymidine, protein content, and cell number. Similar results were obtained with high pressure liquid chromatography-purified TGF-beta in the presence of epidermal growth factor (EGF) (a type of TGF-alpha). By itself, purified TGF-beta was not mitogenic; it depended absolutely on EGF. However, only TGF-beta along with EGF, and not EGF alone, induced a marked morphologic change: a piling up of cells into foci resembling those commonly seen in primary cultures of rheumatoid synovial cells. Mitogenic responses induced by the TGF-beta-EGF combination were prevented by all-trans-retinoic acid but not by indomethacin or dexamethasone. The data indicate that TGF-beta, a peptide extracted from normal cells, can act in concert with EGF to cause proliferation and piling up of synovial cells and raise the possibility that these factors may play a role in rheumatoid arthritis and other proliferative but nonmalignant diseases as well.     

Profibrogenic transforming growth factor-beta/activin receptor-like kinase 5 signaling via connective tissue growth factor expression in hepatocytes

Connective tissue growth factor (CTGF) is important for transforming growth factor-beta (TGF-beta)-induced liver fibrogenesis. Hepatic stellate cells have been recognized as its major cellular source in the liver. Here we demonstrate the induction of CTGF expression in hepatocytes of damaged livers and identify a molecular mechanism responsible for it. CTGF expression was found by immunohistochemistry in bile duct epithelial cells, hepatic stellate cells, and hepatocytes in fibrotic liver tissue from patients with chronic hepatitis B infection. Similarly, CTGF expression was induced in hepatocytes of carbon tetrachloride-treated mice. CTGF expression and secretion were detected spontaneously in a medium of hepatocytes after 3 days of culture, which was enhanced by stimulation with TGF-beta. TGF-beta-induced CTGF expression was mediated through the activin receptor-like kinase 5 (ALK5)/Smad3 pathway, whereas activin receptor-like kinase 1 activation antagonized this effect. CTGF expression in the liver tissue of TGF-beta transgenic mice correlated with serum TGF-beta levels. Smad7 overexpression in cultured hepatocytes abrogated TGF-beta-dependent and intrinsic CTGF expression, indicating that TGF-beta signaling was required. In line with these data, hepatocyte-specific transgenic Smad7 reduced CTGF expression in carbon tetrachloride-treated animals, whereas in Smad7 knockout mice, it was enhanced. Furthermore, an interferon gamma treatment of patients with chronic hepatitis B virus infection induced Smad7 expression in hepatocytes, leading to decreased CTGF expression and fibrogenesis. CONCLUSION: Our data provide evidence for the profibrogenic activity of TGF-beta directed to hepatocytes and mediated via the up-regulation of CTGF. We identify ALK5-dependent Smad3 signaling as the responsible pathway inducing CTGF expression, which can be hindered by an activated activin receptor-like kinase 1 pathway and completely inhibited by TGF-beta antagonist Smad7.     

日本血吸虫病肝纤维化小鼠肝脏CTGF、TGFβ_1-mRNA的表达及意义

目的研究结缔组织生长因子(connective tissue growth factor,CTGF)mRNA与转化生长因子-β1(transforminggrowth factor-beta1,TGFβ-1)mRNA在日本血吸虫病肝纤维化小鼠肝脏中的表达及意义。方法用昆明小鼠感染尾蚴复制小鼠日本血吸虫病肝纤维化模型,模型组分别在6、10、14、18周杀鼠,治疗组在6周时予吡喹酮治疗后10、14、18周杀鼠;masson染色并图像分析进行胶原半定量;RT-PCR检测小鼠肝脏CTGFmRNA、TGFβ-1mRNA表达。结果模型组10周时小鼠血吸虫病肝纤维化形成,胶原量进行性增加,肝脏CTGFmRNA表达达高峰,10周、14周、18周时与治疗组相比均有明显的统计学差异(P均<0.01);模型组TGFβ-1mRNA表达水平和CTGFmRNA有相同的变化趋势,但18周时与治疗组已无明显差别(P>0.05);模型组CTGFmRNA和TGF-β1mRNA的表达具有直线相关性。结论CTGF与TGF-β1的基因表达与小鼠日本血吸虫病肝纤维化形成有密切关系;TGF-β1的致纤维化作用可能部分通过CTGF的生物学作用介导;通过阻断CTGF的传导通路可能是肝纤维化治疗的有效靶点。     

转化生长因子β1和结缔组织生长因子在小鼠血吸虫病肝纤维化中的表达

目的建立血吸虫病肝纤维化小鼠模型,观察转化生长因子β1(TGF-β1)和结缔组织生长因子(CTGF)在小鼠血吸虫肝纤维化中的表达状况。方法 30只BALB/c小鼠随机分为模型组和对照组(每组15只),模型组小鼠以腹部贴片法经皮肤攻击感染日本血吸虫尾蚴(30±1)条,分别于感染后第4、6、8、10和12周两组各取3只小鼠摘眼球取血,测定血清中丙氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST)水平;采血后处死小鼠取肝组织,常规切片,经HE染色后观察各组小鼠肝组织的病理学改变,Masson染色后观察肝组织胶原显微增生情况;免疫组织化学和荧光定量PCR方法检测小鼠肝组织中TGF-β1、CTGF的蛋白和mRNA表达水平。结果感染后6～12周,模型组的ALT和AST水平与同期对照组比较差异统计学意义(P<0.05)。感染12周时,模型组的ALT和AST水平分别为(173.53±31.12)U/L和(301.00±34.87)U/L均高于对照组的[(42.00±3.53)U/L和(96.58±11.26)U/L]。肝组织切片经HE染色后发现,模型组的肝组织有虫卵肉芽肿沉积.汇管区的纤维化特别明显,呈干线性纤维化改变,切面上见门静脉分支周围纤维组织增生呈树枝状分布;Masson染色显示,模型组的肝组织胶原纤维增生面积于感染后8周明显增加,感染后12周为(23.83±1.68)%,与对照组[(1.23±0.14)%]的比较,差异有统计学意义(P<0.05)。感染后10和12周,模型组的TGF-β1[(22.34±2.58)%和(25.82±3.01)%]和CTGF[(11.32±2.44)%和(14.51±2.05)%]的蛋白阳性区域面积与对照组[(2.56±0.87)%和(1.09±0.73)%]的比较,差异有统计学意义(P<0.05)。感染后6、8、10和12周,模型组的TGF-β1和CTGF mRNA相对转录水平呈上升趋势,与同时段对照组的比较差异均有统计学意义(P<0.05);其中在感染后10周时,TGF-β1 mRNA相对转录水平最高,为0.0721±0.0187,对照组的则为0.0089±0.0037;在感染后12周时,CTGF mRNA相对转录水平最高,为0.1136±0.0365,对照组的则为0.0293±0.0184;CTGF mRNA相对转录水平与日本血吸虫感染时间有明显的相关性(r=0.927,P<0.05)。结论 BALB/c小鼠感染日本血吸虫后,肝组织中TGF-β1和CTGF蛋白阳性表达类型和表达分布区域基本一致,CTGF mRNA的相对转录水平与日本血吸虫感染时间有明显相关性。     

Type beta transforming growth factor is an inhibitor of myogenic differentiation.

We have investigated the effect of type beta transforming growth factor (TGF-beta) on the differentiation of skeletal muscle myoblasts. TGF-beta potently (ID50 approximately 10 pM) prevents established cell lines and primary cultures of rat and chicken embryo myoblasts from fusing into multinucleated myotubes. Inhibition of morphological differentiation by TGF-beta correlates with inhibition of the expression of muscle-specific mRNAs and proteins, strong induction of extracellular matrix type I collagen and fibronectin, and a marked tendency of the treated myoblasts to aggregate into densely multilayered arrays or clusters. Myogenic differentiation can resume after removal of TGF-beta from the medium. Examination of the time of action of TGF-beta shows that myoblasts stochastically reach a point beyond which they become insensitive to the inhibitory action of TGF-beta. This resistance of committed myoblasts to the inhibitory action of TGF-beta is not associated with any measurable change in the number or affinity of TGF-beta receptors in those cells. The results indicate that TGF-beta is a potent inhibitor of myogenesis and may regulate muscle development in vivo.     

日本血吸虫病小鼠肝纤维化肝脏CTGF、TGF-β1的表达及意义

目的 研究结缔组织生长因子（connective tissue growth factor，CTGF）与转化生长因子β1（transforming growth factor-betal，TGF-β1）在日本血吸虫病小鼠肝纤维化肝脏中的表达状况及意义。方法 用昆明小鼠感染尾蚴建立日本血吸虫病小鼠肝纤维化模型，随机分为模型组和对照组，感染后6、10、14、18周杀鼠；HE染色观察肝脏病理变化，免疫组化法检测肝内CTGF、TGF-β1蛋白的表达水平。结果 模型组小鼠10周时形成血吸虫病肝纤维化，此时肝内CTGF表达达高峰。且10、14、18周时的表达量均显著高于同期对照组（P〈0．01）；模型组TGF-β1蛋白定量和CT—GF有相同的变化趋势，但18周时与同期对照组比较差异无显著性（P〉0．05）；模型组CTGF和TGF-β1蛋白表达水平具有直线相关性。结论 CTGF与TGF-β1的表达与日木血吸虫病小鼠肝纤维化形成有密切关系，TGF-β1的致纤维化作用可能部分通过CTGF的生物学作用介导，阻断CTGF的传导通路可能是血吸虫病肝纤维化治疗的有效靶点。     

Mammalian dwarfins are phosphorylated in response to transforming growth factor beta and are implicated in control of cell growth.

The dwarfin protein family has been genetically implicated in transforming growth factor beta (TGF-beta)-like signaling pathways in Drosophila and Caenorhabditis elegans. To investigate the role of these proteins in mammalian signaling pathways, we have isolated and studied two murine dwarfins, dwarfin-A and dwarfin-C. Using antibodies against dwarfin-A and dwarfin-C, we show that these two dwarfins and an immunogenically related protein, presumably also a dwarfin, are phosphorylated in a time- and dose-dependent manner in response to TGF-beta. Bone morphogenetic protein 2, a TGF-beta superfamily ligand, induces phosphorylation of only the related dwarfin protein. Thus, TGF-beta superfamily members may use overlapping yet distinct dwarfins to mediate their intracellular signals. Furthermore, transient overexpression of either dwarfin-A or dwarfin-C causes growth arrest, implicating the dwarfins in growth regulation. This work provides strong biochemical and preliminary functional evidence that dwarfin-A and dwarfin-C represent prototypic members of a family of mammalian proteins that may serve as mediators of signaling pathways for TGF-beta superfamily members.     

Transforming growth factor beta 1: an autocrine regulator of adrenocortical steroidogenesis

Transforming growth factor beta 1 (TGF beta 1) is a member of a large family of structurally related regulatory polypeptides which comprises both functionally similar (TGF beta 1, TGF beta 2, TGF beta 3, TGF beta 4 and TGF beta 5) and functionally distinct proteins. In the past few years, TGF beta 1 has emerged as a multifunctional protein. One of its remarkable properties is its capacity to negatively modulate the differentiated, steroidogenic adrenocortical functions. We present here a review of the results from our recent work related to the effects of TGF beta 1 on bovine adrenocortical cell (zona fasciculata-reticularis) functions. We identified the steroid 17 alpha-hydroxylase (P-450 17 alpha) biosynthetic enzyme and the angiotensin II receptor as major targets whose expression are negatively regulated by TGF beta 1 in these cells. We characterized TGF beta 1 receptors at the surface of adrenocortical cells (mainly type I and type III receptors) and observed that their number is increased under ACTH treatment. Furthermore, we could detect the presence of immunoreactive TGF beta 1 in the bovine adrenal cortex whereas it was undetectable in the adrenal medulla and in the capsule. We also observed that adrenocortical cells secrete TGF beta 1 under a latent form together with large amounts of alpha 2-macroglobulin, a protease inhibitor known to be implied in the latency of TGF beta in serum. Taken together, these observations led us to a working hypothesis, proposing TGF beta 1 as an autocrine and/or paracrine regulator of adrenocortical steroidogenic functions. This concept points out the physiological activation of the latent TGF beta 1 complex as the important limiting step controlling its action in the adrenal cortex.     

Tamoxifen downregulates connective tissue growth factor to ameliorate peritoneal fibrosis

Peritoneal fibrosis (PF), including simple sclerosis and encapsulating peritoneal sclerosis (EPS), is a serious complication in patients on long-term peritoneal dialysis. Tamoxifen has successfully been used in treating EPS; however, the mechanism of tamoxifen in treating EPS fibrosis disorders remains unclear. This study demonstrates a possible antifibrotic mechanism of tamoxifen. A bleach-induced PF rat model was applied as the in vivo treatment target. Tamoxifen was intraperitoneally injected daily to treat PF. The PF scores and thickness of the submesothelial zone over the liver surface were measured as indicators for the severity of PF. Human peritoneal mesothelial cells (HPMC) were used as an in vitro model to test the antifibrotic effect of tamoxifen. Gene expressions of transforming growth factors-β (TGF-β), connective tissue growth factor (CTGF) and collagen were investigated using quantitative polymerase chain reactions. In HPMC, tamoxifen showed paradoxical effects between collagen I and TGF-β. Tamoxifen also inhibited TGF-β-induced collagen and CTGF. The possible antifibrotic effect of tamoxifen is through inhibiting CTGF to block collagen synthesis, although it enhances TGF-β which increases fibrosis. These results provide a possible molecular mechanism for tamoxifen.