Role of connective growth factor in plasminogen activator inhibitor-1 and fibronectin expression induced by transforming growth factor β1 in renal tubular cells

Background Connective tissue growth factor (CTGF) contributes greatly to renal tubulointerstitial fibrosis, which is the final event leading to end-stage renal failure. This study was designed to investigate the effects of CTGF antisense oligodeoxynucleotides (ODNs) on the expressions of plasminogen activator inhibitor-1 (PAI-1) and fibronectin in renal tubular cells induced by transforming growth factor β1 (TGF-β) in addition to the role of CTGF in the accumulation and degradation of renal extracellular matrix (ECM). Methods A human proximal tubular epithelial cell line (HKC) was cultured in vitro. Cationic lipidmediated CTGF antisense ODNs were transfected into HKC cells. After HKC cells were stimulated with TGF-β1 (5 μg/L), the mRNA levels of PAI-1 and fibronectin were measured by RT-PCR. Intracellular PAI-1 protein synthesis was assessed by flow cytometry. The secreted PAI-1 and fibronectin in the medium were determined by Western blot and ELISA, respectively. Results TGF-β was found to induce tubular CTGF, PAI-1, and fibronectin mRNA expression. PAI-1 and fibronectin mRNA expression induced by TGF-β was significantly inhibited by CTGF antisenes. ODNs CTGF antisense ODNs also inhibited intracellular PAI-1 protein synthesis and lowered the levels of PAI-1 and fibronectin protein secreted into the medium. Conclusions CTGF may play a crucial role in the accumulation and degradation of excessive ECM during tubulointerstitial fibrosis, and transfecting CTGF antisense ODNs may be an effective way to prevent renal fibrosis.     

The Effect of Connective Tissue Growth Factor on Human Renal Tubular Epithelial Cell Transdifferentiation

Summary To investigate the role of connective tissue growth factor (CTGF) in transdifferentiation of human renal tubular epithelial cell (HKC),in vitro cultured HKC cells were divided into 3 groups: negtive control, low dose CTGF-treated group (rh CTGF, 2.5 ng/ml) and high dose CTGF-treated (rhCTGF, 5. 0 ng/ml). Then the expression of α-smooth muscle actin (α-SMA) were assessed by indirect immuno-fluorescence, and the percentage of α-SMA positive cells were assessed by flow cytometry. RT-PCR were also performed to examine the mRNA level of α-SMA. Upon the stimulation of different concentrations of rhCTGF, the expression of α-SMA were markedly stronger than that in negative controls. The percentages of α-SMA positive cells were significantly higher in the stimulated groups than that of negative controls (38.9%, 65.5% vs 2.4%,P<0.01). α-SMA mRNA levels were also up-regulated by the stimulation of rhCTGF (P<0.01). These results suggest that CTGF can promote the transdifferentiation of human renal tubular epithelial cells towards myofibroblast (Myo-F). ZHANG Chun, male, born in 1977, M. D., Ph. D. This work was supported by a grant from the Science & Technology Foundation of Hubei Province (No. 2003AA301C14).     

肝细胞生长因子对高糖及结缔组织生长因子培养的肾小管上皮细胞纤维化的影响

目的：探讨肝细胞生长因子（HGF）对高糖及结缔组织生长因子（CTGF）诱导肾小管上皮细胞（HKC）纤维化的影响.方法：体外培养HKC,分别在高糖及CTGF环境下加入不同浓度人重组肝细胞生长因子（rhHGF）,以RT-PCR检测转化生长因子β1（TGF-β1）、CTGF、以及纤维化指标Ⅳ型胶原（COL4A1）、纤连蛋白（FN）、α平滑肌肌动蛋白（α-SMA）等的基因表达.结果：高糖及CTGF刺激下,细胞因子和纤维化指标表达均不同程度增加,其中,CTGF作用下,COL4A1表达明显低于高糖组（P＜0.01）.高糖及CTGF环境下加入rhHGF后,纤维化指标显著降低（P＜0.01）,其中高糖＋rhHGF组,CTGF表达减少,TGF-β1表达无明显改变（P＞0.05）.结论：HGF可通过抑制TGF-β下游因子CTGF的表达,发挥抗肾小管上皮细胞纤维化作用,但CTGF并不是其惟一的阻断途径.     

外源性结缔组织生长因子对人肾小管上皮细胞转分化及细胞外基质合成的作用

目的:探讨外源性结缔组织生长因子(CTGF)在人肾小管上皮细胞转分化及细胞外基质合成中的作用.方法:将体外培养的人肾小管上皮细胞HK2分为三组:对照组;CT-GF小剂量组(终浓度为2.5 μg/L);CTGF大剂量组(终浓度为20 μg/L).用倒置显微镜观察细胞形态学变化;噻唑蓝(MTr)法检测细胞增殖活性;RT-PCR检测HK2细胞E-钙黏蛋白(E-cadherin),α-平滑肌肌动蛋白(α-SMA),纤连蛋白(FN)和胶原ⅠαmRNA水平的变化;免疫组织化学方法观察HK2细胞FN和胶原Ⅰ的表达.结果:CTGF刺激使HK2细胞由椭圆形变为梭形,同时促进HK2细胞增殖.不同浓度的CTGF作用于HK2细胞48 h后,α-SMA和FN mRNA水平显著升高(P＜0.05),E-钙黏蛋白mRNA的表达显著下降(P＜0.05);大剂量CTGF刺激HK2细胞48 h后胶原ⅠαmRNA水平显著升高(P＜0.05).小剂量CTGF组HK2细胞胞质FN表达水平显著增加(P＜0.05),大剂量CTGF组HK2细胞胞质表达FN和胶原Ⅰ均显著增加(P＜0.05).结论:CTGF在体外能够诱导人肾小管上皮细胞转分化,并促进FN的合成,大剂量的CTGF可以增加其胶原Ⅰ的合成.     

结缔组织生长因子反义寡核苷酸抑制TGFβ1诱导人肾小管上皮细胞转分化

目的探讨转化生长因子β-1(TGFβ1)诱导人肾小管上皮-肌成纤维细胞转分化(TEMT)过程中结缔组织生长因子(CTGF)的表达和作用.方法在用MTT比色、荧光分析证明阳离子脂质体(DOTAP)介导CTGF反义寡核苷酸(AS)转染HKC可行的基础上,将培养的HKC分为4组正常对照组(C组);TGFβ1组(T组);TGFβ1加AS组(T+AS组);4、TGFβ1加CTGF错义寡核苷酸组(T+SC组).分组处理96h后,分别采用免疫组化、Western blot和RT-PCR技术检测各组CTGF、α-平滑肌肌动蛋白(α-SMA)的表达,并分析CTGF和α-SMA表达量的相关性.结果C组CTGF和α-SMA表达阴性;T组CTGF和α-SMA表达阳性;T+AS组CTGF和α-SMA表达阳性,但皆显著低于T组(P＜0.01)T+SC组CTGF和α-SMA表达皆和T组无显著差异(P＞0.05).相关分析CTGF和α-SMA在表达量上皆呈较强的线性相关性.结论CTGF的AS能有效地抑制TGFβ1所诱导的TEMT,提示CTGF是TGF β1诱导TEMT所必需的成份.     

结缔组织生长因子对人肾小管上皮细胞株生物学特性的影响

目的:观察重组人结缔组织生长因子(rhCTGF)对人肾小管上皮细胞株(HK-2)的作用.方法:将体外培养的人肾小管上皮细胞分为三组:对照组、rhCTGF 5.0 ng/ml, rhCTGF 10.0 ng/ml.应用MTT法检测CTGF对HK-2增殖的影响;倒置显微镜观察细胞形态学的变化;间接酶标免疫组织化学方法检测E-钙粘蛋白(E-Cadherin),α-平滑肌肌动蛋白(α-SMA)的表达;流式细胞术检测α-SMA阳性的HK-2细胞百分数.结果:在一定的浓度范围内,CTGF能促进HK-2细胞的增殖, CTGF促使HK-2细胞由椭圆形转变为梭形状,可下调E-Cadherin,上调α-SMA, 流式细胞测得三组细胞阳性百分率依次为1.54%,10.24%,25.8%(P＜0.05).结论:CTGF在体外促进HK-2转分化的同时促进HK-2的生长.     

针对CTGF的shRNA抑制TGFβ1诱导人肾小管上皮细胞合成胶原

目的研究针对结缔组织生长因子(connective tissue growth factor,CTGF)的短发夹RNA(short hairpin RNA,shRNA)对转化生长因子β1(TGFβ1)诱导人肾小管上皮细胞株(human renal tubular epithelial cell,HKC)合成胶原的抑制作用.方法设计和构建带有U6启动子的能产生针对CTGF的shRNA的RNA干扰表达质粒,转染至受TGF β1刺激的HKC,以RT-pCR和Western blot检测HKC转染前后CTGF表达,以3H脯氨酸掺入法检测总胶原合成量.结果和仅受TGFβ1刺激组相比,转染了RNA干扰表达质粒的受TGFβ1刺激的HKC CTGFmRNA和蛋白表达明显减弱,总胶原合成量下降(P＜0.01).结论针对CTGF的短发夹RNA能明显抑制TGF β1诱导HKC合成胶原.     

针对结缔组织生长因子的siRNA对高糖诱导人肾小管上皮细胞肥大的影响

目的 观测人肾小管上皮细胞转染针对结缔组织生长因子(CTGF)的siRNA后对高糖诱导细胞肥大的影响.方法 细胞分6组培养:正常对照组(培养基含D-葡萄糖1 g/L),等渗对照组(培养基含D-葡萄糖1 g,L、甘露醇3.5 g/L),高糖组(培养基含D-葡萄糖4.5 g/L),高糖+空白对照组(细胞转染空质粒后培养于高糖培养基中),高糖+阴性对照组(细胞转染含无关序列的质粒后培养于高糖培养基中),高糖+干扰组(细胞转染针对CTGF的siRNA表达质粒后培养于高糖培养基中).收集各组培养至24、48、96 h的细胞,以实时PCR检测CTGF mRNA水平;Western blotting检测CTGF蛋白水平;MTT法测定细胞增殖活力;流式细胞仪测定细胞周期分布;考马氏亮蓝法测定细胞总蛋白含量.结果 高糖刺激可上调HK-2细胞的CTGFmRNA及蛋白水平,使停留于G_1期的细胞比例升高,增殖活力受抑制,细胞肥大指标胞内总蛋白含量增加:而通过特异性siRNA抑制CTGF mRNA表达后,细胞的CTGF蛋白表达随时间延长进行性降低.细胞增殖活力增强,更多的细胞由G_1期进入S期,细胞内总蛋白含量降低.结论 证实了CTGF是高糖诱导HK-2细胞肥大的重要介质.针对CTGF的siRNA能明显改善高糖诱导的肾小管上皮细胞肥大,为进一步寻找DN防治的靶点提供了新的实验依据.

Abstract：

Objective To observe the effect of transfection with small interfering RNA (siRNA) targeting connective tissue growth factor (CTGF) on human tubular epithelial hypertrophy induced by high glucose. Methods HK-2 cells were cultured in DMEM/F12 medium containing 1 g/L glucose (normal control group), 4.5 g/L glucose (high glucose group), or 1 g/L glucose + 3.5 g/L mannitol (iso-osmolar control group). The cells were transfected with pGenesil-1, pGenesil/neg, or pGenesil/siRNA-CTGF and then cultured in DMEM/F12 medium containing 4.5 g/L glucose as the high glucose + blank control group, high glucose +negative control group and high glucose+ interference group, respectively. After cell culture for 24, 48 and 96 h, the cells were collected to detect the mRNA and protein levels of CTGF by real-time PCR and Western blotting, respectively. The proliferative activities of the cells were evaluated with MTT assay, and the total cellular protein contents were determined with Bradford method. Flow cytometry was employed to analyzed the cell cycle changes. Results High-glucose significantly up-regulated the CTGF mRNA and protein levels in HK-2 cells. The cell proliferation was inhibited after high-glucose exposure with increased cell percentage in G, phase and total cellular protein content suggesting cellular hypertrophy. Transfection with siRNA targeting CTGF significantly inhibited high glucose-induced up-regulation of CTGF mRNA and protein and promoted the cell proliferation, resulting also increased cells in S phase and lowered total cellular protein contents. Conclusion CTGF is an important mediator of high glucose-induced tubular epithelial hypertrophy, and transfection with siRNA targeting CTGF can alleviate the hypertrophy, suggesting the potential value of CTGF-targeted treatment in the management of diabetic nephropathy.     

脂氧素A4拮抗CTGF所致的人肾小管上皮细胞转分化

目的:探讨脂氧素A4(LXA4)对结缔组织生长因子(CTGF)诱导的肾小管上皮细胞HK2转分化的影响.方法:在体外培养的人肾小管上皮细胞(HK2细胞)中,加入CTGF和LXA4刺激48 h后,用倒置显微镜观察细胞形态学变化,应用RT-PCR、Western blot方法测定上皮细胞E钙黏蛋白和α-平滑肌肌动蛋白(α-SMA)mRNA与蛋白的表达.结果:CTGF刺激使HK2细胞形态由椭圆形转为梭形,下调E钙黏蛋白mRNA与蛋白表达,上调α-SMA的mRNA与蛋白表达.LXAc能够抑制CTGF所致的上述变化,E钙黏蛋白mRNA与蛋白的相对表达值分别为0.270±0.082和0.827±0.177,分别高于CTGF刺激组的0.067±0.015(P<0.05)和0.257±0.221(P<0.05);α-SMA的mRNA与蛋白表达的相对表达值分别为0.070±0.046和0.023±0.023,分别低于CTGF刺激组的0.653±0.256(P<0.05)和0.167±0.050(P<0.05).结论:外源性CTGF能导致HK2细胞转分化为肌成纤维细胞.LXA4可抑制CTGF对HK2细胞的转分化,这为治疗肾间质纤维化提供了一条新途径.     

酸性成纤维细胞生长因子诱导大鼠肾小管上皮细胞转分化的作用及机制

目的　探讨酸性成纤维细胞生长因子 (AcidfibroblastgrowthfactoraFGF)在大鼠肾小管上皮细胞株 (NRK)转分化中的作用 ,为肾小管 间质纤维化的防治提供理论依据。方法　在NRK细胞的培养基内加入不同剂量的重组人aFGF ,并在Ⅰ型胶原处理过及未处理的玻璃表面 ,无血清培养 6d。使用透射电镜、免疫细胞化学对肾小管上皮细胞向肌成纤维细胞形态及表型的转变进行评估。结果　不同剂量的aFGF(1、1 0、50ng/ml)处理后的NRK细胞形态和表型发生不同程度的改变 :体积增大、失去尖端 基底极性和微绒毛、细胞延长、具有浸润特征的前后向双末端极性、出现肌动蛋白中间丝结构。免疫组化和Westernblot分析显示加入aFGF后角蛋白表达减少 ,有肌成纤维细胞的特异性标志物α 平滑肌动蛋白 (α SMA)的表达。α SMA阳性细胞的比例与aFGF的浓度呈正相关 ,亲和抗aFGF抗体可消除这种转分化现象。加入aFGF后 ,在玻璃表面α SMA阳性细胞数 (34 4± 0 0 90 ) %较Ⅰ型胶原处理培养表面α SMA阳性细胞数 (74 6± 0 1 0 1 ) %有显著差异 (P <0 0 5)。结论　aFGF在促进肾小管上皮细胞向肌成纤维细胞转分化的过程中有重要的意义 ,该过程亦与细胞的生长环境有关 ,提示肾小管上皮细胞的表型转化是肾间质纤维化的重要原因     

罗格列酮对高糖大鼠肾小管上皮细胞表达转化生长因子β1和纤维连接蛋白的影响

目的:观察罗格列酮(rosiglitazone,RGZ)对高糖环境下大鼠肾小管上皮细胞(NRK52E)转化生长因子β1(TGF_β1)和纤维连接蛋白(FN)表达的影响,初步探讨罗格列酮对糖尿病肾病的保护作用。方法:体外培养大鼠肾小管上皮细胞,分成正常对照组NG(含1000mg/LD_葡萄糖)、高糖组HG(含4500mg/LD_葡萄糖)、HG+RGZ(5μmol/L)组、HG+RGZ(10μmol/L)组和HG+RGZ(15μmol/L)组,用蛋白印迹的方法(Westernblotting)检测TGF_β1和FN蛋白表达的改变。结果:HG组细胞TGF_β1和FN的蛋白水平较NG组显著升高,加入罗格列酮后,TGF_β1和FN的表达较HG组降低。结论:罗格列酮可以抑制高糖诱导的小管细胞TGF_β1和FN高表达,具有一定的肾保护作用。     

脂氧素A4抑制结缔组织生长因子诱导的肾小管上皮细胞表达整合素连接激酶

目的:结缔组织生长因子(connective tissue growth factor,CTGF)可诱导人肾小管上皮细胞HK-2表达整合素连接激酶(integrin-linked kinase,ILK),本研究观察脂氧素A4(lipoxinA4,LXA4)是否调节CTGF对合成ILK的作用,并探讨其作用机制。方法:对体外培养的人肾小管上皮细胞(HK-2细胞株),用不同浓度的LXA4预刺激,再加入CTGF共同孵育;或单用CTGF刺激HK-2细胞。应用RT-PCR和Westernblot方法测定ILKmRNA和蛋白表达,应用Westernblot法测定分裂原激活的蛋白激酶(p42/44mitogen-activated protein kinase,p42/44MAPK)(也称为ERK1/2)、磷脂酰肌醇3-激酶(phosphoinositide 3-kinase,PI3-K)。结果:CTGF刺激使HK-2细胞ILKmRNA表达和蛋白合成增加,磷酸化ERK1/2、磷酸化PI3-K的表达增加。LXA4呈剂量依赖性地抑制CTGF所致的上述变化。结论:LXA4可抑制CTGF引起的HK-2细胞表达ILK,其机制依赖于抑制...     

IGF-Ⅰ对人肾小管上皮细胞转分化相关基因表达的影响

目的:探讨胰岛素样生长因子-Ⅰ(IGF-Ⅰ)在人肾小管上皮细胞转分化中的作用。方法:将体外培养的人肾小管上皮细胞(HK2)分为对照组和IGF-Ⅰ组:培养液中加入IGF-Ⅰ,终浓度分别为25、50、100、200ng/ml。倒置显微镜观察细胞形态变化。用逆转录-聚合酶链反应(RT-PCR)技术测定HK2细胞E-钙黏蛋白、角蛋白、α-平滑肌肌动蛋白(α-SMA)、波形蛋白和纤连蛋白(FN)mRNA水平的变化。结果:IGF-Ⅰ刺激使HK2细胞形态由椭圆变为梭形。不同浓度的IGF-Ⅰ作用于HK2细胞48h后E-钙黏蛋白和角蛋白mRNA的表达显著下降(P<0.05),α-SMA、波形蛋白和FNmRNA水平显著升高(P<0.01),且呈剂量依赖性。结论:IGF-Ⅰ在体外能刺激人肾小管上皮细胞向肌成纤维细胞(MyoF)转分化,并促进其合成细胞外基质(ECM)。     

CTGF反义寡核苷酸对人肾小管上皮细胞转分化的影响

目的研究结缔组织生长因子（CTGF）反义寡核苷酸（ASODN）对人肾小管上皮细胞（HKC）转分化的影响。方法用巨噬细胞趋化因子-1（MCP-1）和马兜铃酸Ⅰ（AAⅠ）联合诱导HKC转分化模型。实验设空白对照组、模型对照组、PEI组、CTGFASODN10ng/mL组和CTGF ASODN100ng/mL组,分别采用WST-8法、流式细胞术、RT-PCR法、细胞免疫组织化学法检测不同浓度的CTGF ASODN对HKC转分化模型细胞增殖和细胞周期的影响,以及α-SMA mRNA表达和α-SMA、TGF-β1、Fibronectin（FN）蛋白表达的变化。结果 100ng/mL的CTGF ASODN对MCP-1和AAⅠ联合诱导HKC转分化细胞具有促进细胞增殖的作用,并可减少实验模型导致的细胞S期阻滞,降低α-SMA mRNA表达,减少α-SMA、TGF-β1和FN蛋白的表达。结论 CTGFASODN能够抑制MCP-1和AAⅠ导致的人HKC转分化。     

CTGF反义寡核苷酸对人肾小管上皮细胞转分化的影响

目的 研究结缔组织生长因子(CTGF)反义寡核苷酸(ASODN)对人肾小管上皮细胞(HKC)转分化的影响.方法 用巨噬细胞趋化因子-1(MCP-1)和马兜铃酸Ⅰ(AAⅠ)联合诱导HKC转分化模型.实验设空白对照组、模型对照组、PEI组、CTGF ASODN 10 ng/mL组和CTGF ASODN 100 ng/mL组,分别采用WST-8法、流式细胞术、RT-PCR法、细胞免疫组织化学法检测不同浓度的CTGF ASODN对HKC转分化模型细胞增殖和细胞周期的影响,以及α-SMA mRNA表达和α-SMA、TGF-β1、Fibronectin(FN)蛋白表达的变化.结果 100 ng/mL的CTGF ASODN对MCP-1和AAⅠ联合诱导HKC转分化细胞具有促进细胞增殖的作用,并可减少实验模型导致的细胞S期阻滞,降低α-SMA mRNA表达,减少α-SMA、TGF-β1和FN蛋白的表达.结论 CTGF ASODN能够抑制MCP-1和AAⅠ导致的人HKC转分化.     

氯沙坦对糖尿病大鼠肾脏细胞因子表达的影响及意义

目的探讨氯沙坦治疗糖尿病肾病的作用及其机制。方法采用单侧肾切除的STZ诱导的糖尿病大鼠，观测其肾脏形态、功能的变化。同时，采用荧光实时定量RT-PCR方法检测TGF—β1、CTGF、PAI-1等细胞因子在糖尿病大鼠肾脏中的表达情况。结果与正常组（NC组）相比，8周时糖尿病肾病组（DN组）大鼠的肾脏肥大指数（KW／BW）、平均肾小球体积（VG）、尿白蛋白排泄率（UAER）、肌酐清除率（Ccr）均升高。DN组肾皮质CTGF、PAI—1、FN表达水平也显着增高（p〈0．05）；与DN组相比较，氯沙坦治疗组的上述指标则均明显下降（p〈0．05）。结论氯沙坦可通遏抑制TGF—β1、CTGF、PAI-1等细胞因子的表达，对糖尿病人鼠肾脏起到保护作用。     

结缔组织生长因子及抗体对体外培养鸡滑膜细胞增殖活性的影响

目的：研究不同浓度结缔组织生长因子（CTGF）及其抗体对鸡肌腱滑膜细胞增殖活性的影响.方法：以来亨鸡屈趾肌腱腱周滑膜组织为材料,经体外分离、培养和鉴定后,加入不同浓度的CTGF（浓度为0,5,10,20,50,100,200,500 ng/ml）及CTGF抗体（浓度为0,1,2,4,8,16,32,64 μg/ml）分组培养滑膜细胞,并以CCK-8染色法检测滑膜细胞的增殖情况.结果：滑膜细胞增殖在CTGF浓度为5 ng/ml至200 ng/ml时,呈逐步递增趋势,各组之间差异有统计学意义（P＜0.05）;而在200 ng/ml及500 ng/ml浓度组间差异无统计学意义（P＞0.05）,加入浓度为4,8,16,32 μg/mlCTGF抗体时,滑膜细胞增殖呈逐步递减趋势,各组之间差异有统计学意义（P＜0.05）;而CTGF抗体浓度为0,1,2 μg/ml和浓度为32,64μtg/ml时,各组间差异无统计学意义（P＞0.05）.结论：CTGF可促进体外培养的鸡肌腱滑膜细胞增殖,最佳浓度为200 ng/ml;CTGF抗体对滑膜细胞增殖活性可产生一定程度的抑制作用.     

结缔组织生长因子在病理性瘢痕中的表达

目的探讨结缔组织生长因子（CTGF）在病理性瘢痕形成中的作用。方法采用半定量逆转录聚合酶链反应技术（RT-PCR）检测10例瘢痕疙瘩（瘢痕疙瘩组）和10例增生性瘢痕（增生性瘢痕组）中的CTGF mRNA的表达,并以8例正常皮肤（正常皮肤组）作为对照。结果病理性瘢痕中CTGF mRNA表达均明显高于正常皮肤组（P〈0.05）,而瘢痕疙瘩组又高于增生瘢痕组（P〈0.05）。结论CTGF在病理性瘢痕的形成过程中起到重要作用。     

Role of connective tissue growth factor in experimental radiation nephropathy in rats

Background Connective tissue growth factor （CTGF） is a potent fibrogenic cytokine which has been associated with progressive glomerulosclerosis and tubulointerstitial fibrosis. We investigated the role of CTGF on the progression of a rat model of radiation nephropathy. Methods The model of radiation nephropathy in rats was established as follows： control group （n=12）, underwent only laparotomy; irradiated group （n=-20）, underwent a laparotomy, then the rats were subjected to a single dose 25 Gy X-ray to the kidneys. The rats were followed up one, three, six and nine months after renal exposure to radiation. Results Renal dysfunction was noted early in irradiated rats. Histological analysis showed focal glomerular sclerotic lesions at an early stage after irradiation. Radiation-induced glomerular and tubulointerstitial injuries were particularly severe the sixth month after irradiation as compared to the control group （P 〈0.01）. By immunohistochemistry, increased expression of CTGF was noted in the irradiated kidneys, which began to increase from the first month after irradiation, and remained significantly higher at the sixth and ninth month after irradiation （P 〈0.01）. Upon Western blot analysis CTGF protein expression showed an increase in the radiation treated kidneys compared with the control rats. The expression of CTGF closely correlated with the progression of radiation nephropathy. The expression of α-smooth muscle actin, vimentin, type Ⅲ collagen and type Ⅳ collagen was also high in the irradiated kidney as compared to control rat kidneys （P 〈0.05）, and was most severe at the sixth and ninth month after irradiation （P 〈0.01）. By double immunostaining, CTGF expressing cells were found to be α-SMA-positive myofibroblasts and vimentin-positive tubular epithelial cells. Glomerular expression of CTGF closely correlated with the glomerular expression of a-SMA （r=0.628, P 〈0.01）, vimentin （r=0.462, P 〈0.05） and accumulation of type IV collagen （r=0.584,