Inhibitory Effect of Sodium Ferulate on the Cardiomyocyte Hypertrophy Induced by AngiotensionⅡ

Objective:To investigate the effects of sodium ferulate(SF) on myocardial hypertrophy of rat and explore the protective mechanism. Methods:The myocardial hypertrophy was induced by 0.1 μmol·L~(-1) Ang II. The cytoactive was detected by MTT. The cultured cardiomyocytes from Sprague Dawley neonate rats were randomly divided into normal,model,L-arginine(L-arg 1 000 μmol·L~(-1)) group and SF(50,100,200 μmol·L~(-1)) group.To observe whether SF had nonspecific injurious effect on the cells,SF 200 μmol·L~(-1) was added into the normal cardiomyocytes and to determine whether the effect of SF on cardiomyocyte hypertrophy was associated with NO release,another two groups were established. NG-nitro-L-arginine-methyl ester(L-NAME) 1 500 μmol·L~(-1) combined with SF 200 μmol·L~(-1) or L-arg 1 000 μmol·L~(-1),respectively. Cardiomyocyte hypertrophy was confirmed by observing the histological changes and the measurements of cell diameter,protein content and ANF and β-MHC m RNA expression of the cells.The levels of NO,NOS and eNOS activity,the contents of cGMP and cAMP. The expression of eNOS were detected by Real time PCR and Western blotting. Results:(1) SF(50,100,200 μmol·L~(-1)) had no obvious side effect on cultured neonatal rat cardiomyocytes in vitro. In the group added 0.1 μmol·L~(-1) Ang Ⅱ alone,the cells displayed swollen,with undistinguishable border;the diameter and protein content of cardiomyocytes was increased remarkably,and the expression of ANF and β-MHC m RNA were up-regulated by Ang Ⅱ. SF and L-arg could ameliorate the cardiomyocyte hypertrophy which can be inhibit by L-NAME.(2) Compared with normal group,0.1 μmol · L~(-1) Ang II could decrease the NO content,NOS and eNOS activity in supernatant of cultured cardiomyocytes,decrease the content of cGMP and increase the content of cAMP incardiomyocytes,upregulation the expression of eNOS.SF-H and L-arg administrated could siginificantly ameliorate these changes. Conclusion:SF can inhibit cardiomyocyte hypertrophy induced Ang Ⅱ in rats. The probable mechanism involved to promote NO-cGMP signaling pathway and up-regulate the expression of eNOS.     

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.     

Effects of Tanshinone ⅡA on Transforming Growth Factor β1-Smads Signal Pathway in Renal Interstitial Fibroblasts of Rats

The effects of tanshinone ⅡA (TSN) on transforming growth factor β1 (TGFβ1) signal transduction in renal interstitial fibroblasts of rats were studied in order to investigate its mechanism in prevention of renal interstitial fibrosis. Rat renal fibroblasts of the line NRK/49F were cultured in vitro, stimulated with 5 ng/mL TGFβ1 and pretreated with 10-6, 10-5, 10-4 mol/L TSN respectively. The mRNA levels of fibronectin (FN) were examined by RT-PCR. The protein expression of FN and Smads was detected by Western blot. TGFβ1 induced the expression of FN mRNA and Smads in a time-dependent manner in a certain range. Compared with pre-stimulation, the FN mRNA and protein levels were increased by 1.1 times and 1.5 times respectively (P<0.01, P<0.01), and the protein expression of phosphorylated Smad2/3 (p-Smad2/3) increased by 7 times at the end of TGFβ1 stimulation (P<0.01). TSN pretreatment may down-regulate the FN and p-Smad2/3 expression in a dose-dependent manner. 10-6 mol/L TSN pretreatment had no effect on the FN and p-Smad2/3 expression (both P>0.05). After pretreatment with 10-5 and 10-4 mol/L TSN, the FN mRNA levels were decreased by 28.1% and 43.8% respectively (P<0.05, P<0.01), the FN protein levels were decreased by 40% and 44% respectively (P<0.05, P<0.05), and the p-Smad2/3 protein expression were decreased by 40% and 65% respectively (P<0.05, P<0.01). The inhibitory effect of TSN on renal interstitial fibrosis may be related to its blocking effect on TGFβ1-Smads signal pathway in renal intersti- tial fibroblasts.     

Effect of Sodium Tanshinone ⅡA Sulfonate on Phosphorylation of Extracellular Signal-regulated Kinasel/2 in Angiotensin Ⅱ-induced Hypertrophy of Myocardial Cells

Objective： To observe the effects of sodium tanshinone ⅡA sulfonate （STS） on angiotensin Ⅱ （Ang Ⅱ）-induced hypertrophy of myocardial cells through the expression of phosphorylated extracellular signal-regulated kinase （p-ERK1/2）. Methods： In the primary culture of neonatal rat myocardial cells, the total protein content in myocardial cells was determined by coomassie brilliant blue and the protein synthesis rate was measured by [3H]-Leucine incorporation as indexes for hypertrophy of myocardial cells. The expression of p-ERK1/2 was determined using Western blot and immunofluorescence labeling. Results： （1） The total protein and protein synthesis rate increased significantly in contrast to the control group after the myocardial cells were stimulated by Ang Ⅱ （1 μ mol/L） for 24 h; STS markedly inhibited the increment of the total protein level induced by Ang Ⅱ and the syntheses of protein. （2） After pretreatment of myocardial cells with Ang Ⅱ （1 μmol/L） for 5 min, the p-ERK1/2 protein expression was increased, with the most obvious effect shown at about 10 min; pretreatment of myocardial cells with STS at different doses （2, 10, 50μmol/L） for 30 min resulted in obvious inhibition of the expression of p-ERK1/2 stimulated by Ang Ⅱ in a dose-dependent manner. （3） After the myocardial cells were stimulated by AngⅡ （1 μ mol/L）, the immunofluorescence of ERK1/2 rapidly appeared in the nucleus. The activation and translocation process of ERK1/2 induced by Ang Ⅱ was blocked distinctly by STS. （Conclusion： STS inhibited the myocardial cell hypertrophy induced by Ang Ⅱ, and the mechanism may be associated with the inhibition of p-ERK1/2 expression.     

Effect of Sodium Tanshinone Ⅱ A Sulfonate on Phosphorylation of Extracellular Signal-regulated Kinase1/2 in Angiotensin Ⅱ-induced Hypertrophy of Myocardial Cells

Objective:To observe the effects of sodium tanshinone Ⅱ A sulfonate(STS)on angiotensin Ⅱ(Ang Ⅱ)-induced hypertrophy of myocardial cells through the expression of phosphorylated extracellular signal-regulated kinase(P-ERK1/2).Methods:In the primary culture of neonatal rat myocardial cells.the total protein content in myocardial cells was determined by coomassie brilliant blue and the protein synthesis rate was measured by[3H]-Leucine incorporation as indexes for hypertrophy of myocardial cells.The expression of p-ERK1/2 was determined using Western blot and immunofluorescence Iabeling.Results:(1)The totaI protein and protein synthesis rate increased significantly in contrast to the control group after the myocardial cells were stimulated by Ang Ⅱ (1 μmol/L)for 24 h;STS markedly inhibited the increment of the total protein level induced by Ang Ⅱ and the syntheses of protein.(2)After pretreatment of myocardial cells with Ang Ⅱ(1 μ mol/L)for 5 min,the p-ERK1/2 protein expression was increased,with the most obvious effect shown at about 10 min;pretreatment of myocardial cells with STS at different doses(2,10,50 μ mol/L)for 30 min resulted in obvious inhibition of the expression of p-ERK1/2 stimulated by Ang Ⅱ in a dose-dependent manner.(3)After the myocardial cells were stimulated by Ang Ⅱ(1 μ mol/L),the immunofluorescence of ERK1/2 rapidly appeared in the nucleus.The activation and translocation process of ERK1/2 induced by Ang Ⅱ was blocked distinctly by STS.Conclusion:STS inhibited the myocardial cell hypertrophy induced by Ang Ⅱ,and the mechanism may be associated with the inhibition of p-ERK1/2 expression.     

Role of Connective Tissue Growth Factor in Extracellular Matrix Degradation in Renal Tubular Epithelial Cells

In order to investigate the effects of connective tissue growth factor (CTGF) antisense oligodeoxynucleotide (ODN) on plasminogen activator inhibitor-1 (PAI-1) expression in renal tubular cells induced by transforming growth factor β1 (TGF-β1) and to explore the role of CTGF in the degradation of renal extracellular matrix (ECM), a human proximal tubular epithelial cell line (HKC) was cultured in vitro. Cationic lipid-mediated CTGF antisense ODN was transfected into HKC. After HKC were stimulated with TGF-β1 (5 μg/L), the mRNA level of PAI-1 was detected by RT-PCR. In-tracellular PAI-1 protein synthesis was assessed by flow cytometry. The secreted PAI-1 in the media was determined by Western blot. The results showed that TGF-β1 could induce tubular CTGF and PAI-1 mRNA expression. The PAI-1 mRNA expression induced by TGF-β1 was significantly inhib-ited by CTGF antisense ODN. CTGF antisense ODN also inhibited intracellular PAI-1 protein syn-thesis and lowered the levels of PAI-1 protein secreted into the media. It was concluded that CTGF might play a crucial role in the degradation of excessive ECM during tubulointerstitial fibrosis, and blocking the biological effect of CTGF may be a novel way in preventing renal fibrosis.     

Effects of Tanshinone ⅡA on Transforming Growth Factor β1-Smads Signal Pathway in Renal Interstitial Fibroblasts of Rats

The effects of tanshinone ⅡA （TSN） on transforming growth factor β1 （TGFβ1） signal transduction in renal interstitial fibroblasts of rats were studied in order to investigate its mechanism in prevention of renal interstitial fibrosis. Rat renal fibroblasts of the line NRK/49F were cultured in vitro, stimulated with 5 ng/mL TGFβ1 and pretreated with 10-6, 10-5, 10-4 mol/L TSN respectively. The mRNA levels of fibronectin （FN） were examined by RT-PCR. The protein expression of FN and Smads was detected by Western blot. TGFβ1 induced the expression of FN mRNA and Smads in a time-dependent manner in a certain range. Compared with pre-stimulation, the FN mRNA and protein levels were increased by 1.1 times and 1.5 times respectively （P〈0.01, P〈0.01）, and the protein expression of phosphorylated Smad2/3 （p-Smad2/3） increased by 7 times at the end of TGFβ1 stimulation （P〈0.01）. TSN pretreatment may down-regulate the FN and p-Smad2/3 expression in a dose-dependent manner. 10-6 mol/L TSN pretreatment had no effect on the FN and p-Smad2/3 expression （both P〉0.05）. After pretreatment with 10-5 and 10-4 mol/L TSN, the FN mRNA levels were decreased by 28.1% and 43.8% respectively （P〈0.05, P〈0.01）, the FN protein levels were decreased by 40% and 44% respectively （P〈0.05, P〈0.05）, and the p-Smad2/3 protein expression were decreased by 40% and 65% respectively （P〈0.05, P〈0.01）. The inhibitory effect of TSN on renal interstitial fibrosis may be related to its blocking effect on TGFβ1-Smads signal pathway in renal intersti- tial fibroblasts.     

Regulation of the expression and function of glucose transporter-1 by TGF-β1 and high glucose in mesangial cells

Objective To study the effects of high glucose and transforming growth factor-β1 (TGF-β1) on the expression and function of glucose transporter-1 (GLUT1) in mouse mesangial cells.Methods Cultured mouse mesangial cells were used.The expression of GLUT1 mRNA was detected by Northern Blot; glucose uptake and its kinetics were determined with a 2-Deoxy-［(3)H］-D-glucose uptake assay.Results Mesangial cells exposed to enriched glucose medium (20 mmol/L) for 72 hours demonstrated a decrease in both GLUT1 mRNA and V(max) for uptake of the glucose analog, 2-deoxy-D-glucose　(2DOG), as compared to mesangial cells cultured in physiologic glucose concentrations(5.5 mmol/L).In contrast, hypertonic mannitol had no effect on GLUT1 mRNA levels.TGF-β1 treatment for 10 hours stimulated 2DOG uptake, both in 5.5 mmol/L and 20 mmol/L glucose medium, by approximately 4.28-fold in a dose-dependent manner (2 ng/ml maximum).Kinetic analysis of 2DOG uptake revealed an increase in V(max) and a decrease in K(m) in the presence of TGF-β1. TGF-β1 also up-regulated the expression of GLUT1 mRNA in mesangial cells.The addition of anti-TGF-β neutralizing antibody (30 μg/ml) in mesangial cells cultured in enriched glucose medium (20 mmol/L) led to a 40% decrease in 2DOG uptake.Conclusions The expression of GLUT1 can be suppressed by exposure of mesangial cells to high glucose medium, which may serve as a protective mechanism against possible adverse effects of excessive glucose flux into cells.TGF-β1 stimulates glucose uptake by enhancing the expression and function of GLUT1 in mesangial cells.This effect is independent of the glucose milieu in the cultured medium.     

蟾蜍灵对高糖诱导大鼠系膜细胞过表达纤维连接蛋白和结缔组织生长因子的影响

目的:观察不同浓度蟾蜍灵对高糖诱导的大鼠系膜细胞(MC)过表达FN及CTGF的影响,拟探讨其防治糖尿病肾病的可能作用?方法:体外培养MC,将细胞分为5组:正常对照组?高糖组?高糖 + 低浓度蟾蜍灵(5 × 10-9 mol/L)组?高糖 + 中浓度蟾蜍灵(5 × 10-8 mol/L)?高糖+高浓度蟾蜍灵组(5 × 10-7 mol/L)?以台盘兰拒染法检测蟾蜍灵对MC的毒性作用,48 h后,采用RT-PCR法和Western-blot法检测各组MC中FN?CTGF mRNA和CTGF蛋白的表达及其变化?结果:蟾蜍灵在5 × 10-9 ~5 × 10-7 mol/L浓度间对MC无明显细胞毒作用?48 h后,与对照组相比,高糖组CTGF mRNA和蛋白以及FN mRNA表达均显著增加(P < 0.05);高?中?低浓度蟾蜍灵干预能显著降低高糖诱导的上述指标表达,且呈浓度依赖效应(P < 0.05)?结论:蟾蜍灵能部分抑制高糖诱导的MC过表达FN,呈浓度依赖效应,其作用可能部分是通过降低促纤维化因子CTGF合成而实现,提示蟾蜍灵在DN纤维化防治领域具有进一步研究的价值?     

槲皮素对活化大鼠肝星状细胞TGF-1信号的影响

目的　了解槲皮素对肝脏星状细胞 (HSCs)通过转化生长因子 (TGF)β1诱导的结缔组织生长因子(CTGF)及纤维连接素 (FN)表达的影响。方法　通过胶原酶与链霉蛋白酶原位灌注、Nycondenz一步法梯度离心分离雄性 Wistar大鼠 HSCs。培养活化的 HSCs无血清饥饿后与 10 - 9～ 10 - 5m ol/ L浓度的槲皮素孵育 2 4 ,4 8或 72h。以流式细胞术测定 TGFβ1的表达与分泌。逆转录聚合酶链反应 (RT- PCR)检测 CTGF基因表达 ,免疫组化检测FN表达。结果　流式细胞术检测免疫荧光强度显示 10 - 8～ 10 - 5m ol/ L浓度槲皮素可抑制 HSCs TGFβ1表达 ;10 - 7mol/ L浓度槲皮素孵育 4 8h可显著抑制 HSCs TGFβ1表达 (特异性平均荧光强度分别为 13.33± 2 .4 4和 18.0 8±2 .5 4 ,t=16 .5 2 ,P<0 .0 1)。 TGFβ1可明显促进活化 HSCs CTGF m RNA表达 ,但 10 - 7mol/ L浓度槲皮素在 72 h内几乎可完全拮抗此效应。与对照相比 ,10 - 7mol/ L浓度槲皮素孵育 4 8h可显著抑制 HSCs FN表达。结论　槲皮素可抑制 TGFβ1信号通路 ,包括抑制 TGFβ1、FN表达及 CTGF的基因表达 ,具有潜在的抗肝纤维化治疗作用。     

转化生长因子β1通过Smad2途径调节足细胞结缔组织生长因子表达

目的　研究肾脏足细胞是否表达结缔组织生长因子 (CTGF)以及TGFβ1对CTGF表达调控的信号途径。方法　以肾小球足细胞为对象 ,应用Western印迹分析技术 ,观察了 3种促进肾脏纤维化的蛋白因子 ,转化生长因子 β1(TGFβ1)、血小板源生长因子 (PDGF)和血管紧张素Ⅱ (AngⅡ )对体外培养的足细胞CTGF蛋白表达的影响 ,以及ERK、Smad两条信号途径在TGFβ1调节CTGF蛋白表达中的影响 ;逆转录 聚合酶链反应 (RT PCR)检测CTGFmRNA的变化。结果　体外培养的足细胞表达基础水平CTGF蛋白 ,2 0ng/mlPDGF和 10 -6mol/LAngII刺激 2 4小时后细胞内CTGF蛋白水平与对照相比差异无显著意义 (P >0 0 5 ) ,而 1ng/mlTGFβ1刺激 2 4h足细胞CTGF蛋白水平显著高于对照 (P <0 0 5 ) ,且增加呈TGFβ1剂量依赖趋势 ;1ng/mlTGFβ1刺激 12h可以使细胞CTGFmRNA表达增加。1ng/mlTGFβ1使足细胞Smad2 和细胞外信号调节激酶 (ERK1/ 2 )磷酸化 ,在刺激 30min达高峰 ;应用丝 /苏氨酸激酶抑制剂Staurosporine抑制Smad2 磷酸化可以消减TGFβ1刺激的CTGF蛋白增加 ,但ERK1/ 2 活化抑制剂PD 980 5 9阻断ERK1/ 2 磷酸化不能减弱TGFβ1刺激CTGF蛋白表达的效应。结论　在足细胞上 ,TGFβ1刺激CTGF表达依赖于Smad2 信号通路的活化 ,而不依赖于ERK1/     

氯沙坦对高糖诱导大鼠肾近端小管上皮细胞纤溶酶原激活物及其抑制物表达的影响

目的 研究高糖对正常大鼠肾近端小管上皮细胞纤溶酶原激活物(tPA和uPA)及其抑制物-1(PAI-1)表达的影响,并探讨血管紧张素Ⅱ受体阻滞剂氯沙坦对其改善作用.方法 培养大鼠肾近端小管上皮细胞,并分组为正常对照组、甘露醇组(5 mmol/L D-葡萄糖 25 mmol/L 甘露醇)、高糖组(30 mmol/L D-葡萄糖)、氯沙坦组(10-3 mmol/L氯沙坦)、高糖 氯沙坦组(30 mmol/L D-葡萄糖 10-3 mmol/L氯沙坦).RT-PCR法检测各组细胞tPA、uPA及PAI-1 mRNA表达. 结果与正常对照组比较,高糖组肾小管上皮细胞tPA和uPA mRNA表达下降(P＜0.01), PAI-1 mRNA表达增加(P＜0.01);氯沙坦可部分逆转高糖的作用,高糖加氯沙坦组tPA、uPA表达分别是高糖组的2.06倍、1.69倍(P＜0.01),PAI-1表达为高糖组的44% (P＜0.01). 结论高糖可使肾近端小管上皮细胞PA/PAI-1 mRNA异常表达, 氯沙坦可以在肾小管中通过维持PA/ PAI-1的平衡,对糖尿病肾病防治起一定的作用.     

螺内酯对醛固酮诱导的大鼠肾小球系膜细胞氧化应激及NF-κB、MCP-1表达的影响

目的观察螺内酯(SPI)对醛固酮(ALD)诱导的大鼠肾小球系膜细胞(MCs)氧化应激和核因子-κB(NF-κB)、单核细胞趋化蛋白-1(MCP-1)表达的影响,探讨其肾脏保护机制。方法体外培养的MCs随机分为正常对照组(NG组)、ALD组(10-7mol/L)、SPI 1组(ALD+SPI 10-7mol/L)、SPI2组(ALD+SPI 10-8mol/L)和SPI 3组(ALD+SPI 10-9mol/L)。以流式细胞仪法检测MCs内活性氧(ROS)水平。RT-PCR法检测NF-κB、MCP-1、醛固酮合成酶(CYP11B 2)、醛固酮受体(MR)和11β-羟类固醇脱氢酶2(11β-HSD 2)的mRNA表达。结果①MCs表达CYP11B 2、MR和11β-HSD 2 mRNA。②与NG组比较,ALD刺激MCs 48 h后,细胞内ROS水平、NF-κB及MCP-1 mRNA表达明显增加。③SPI干预48 h后,与ALD组相比较,SPI 1组、SPI 2组、SPI 3组细胞内ROS水平、NF-κB及MCP-1 mRNA表达明显减少,且呈一定的剂量依赖性。④相关分析显示MCs内ROS水平与NF-κB mRNA表达量呈显著正相关(P<0.01),NF-κBmRNA和MCP-1 mRNA表达量也呈显著正相关(P<0.01)。结论 SPI可在一定程度上抑制ALD诱导的MCs氧化应激,减少NF-κB和MCP-1的表达,该作用可能与其肾脏保护作用部分有关。     

氯沙坦对高糖培养的人系膜细胞血管内皮细胞生长因子表达的影响

目的:探讨氯沙坦对高糖培养的系膜细胞产生活性氧和血管内皮细胞生长因子(VEGF)mRNA表达的影响。方法:体外培养人系膜细胞,用高糖、氯沙坦干预不同时间后,应用比色法检测培养细胞上清液中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活力,丙二醛(MDA)的水平。用RT鄄PCR法测定血管内皮细胞生长因子(VEGF)mRNA表达的影响。结果:与正常对照组相比,高糖组SOD、CAT的活力明显降低,而MDA含量明显升高,VEGFmRNA表达升高。与高糖组相比,高糖加氯沙坦组的SOD、CAT的活力升高,MDA水平下降,VEGFmRNA表达上调。结论:氯沙坦能抑制高糖所致细胞活性氧的产生和VEGF的表达,从而抑制细胞通透性升高,降低蛋白尿,发挥其肾保护作用。     

Effects of angiotensin II and losartan on the growth and proliferation of hepatic stellate cells.

OBJECTIVE: To investigate the effects of angiotensin II (AngII) and AT1a blocker losartan on growth and proliferation of rat hepatic stellate cells (HSCs). METHODS: Rat HSCs were isolated, cultured and identified, followed by incubation with AngII or losartan at different concentrations. The cell growth and proliferation were assessed via cell counting and MTT assay, and the effects of the agents on HSC DNA synthesis evaluated by way of (3)H-thymidine incorporation ((3)H-TDR). RESULTS: AngII (1 x 10(-9) to 1 x 10(-7) mol/L) stimulated HSC proliferation as demonstrated by cell counting, MTT assay and thymidine incorporation test (P < 0.05), but such effect was not observed at lower doses (<1 x 10(-9) mol/L). Losartan had significant inhibitory effect on HSC growth at the concentration of 1 x 10(-8) to 1 x 10(-6) mol/L (P < 0.05), but not at lower doses (<1 x 10(-8) mol/L). Co-stimulation of the cells with losartan and AngII did not result in a significant increase in cell number as compared with the control group (P > 0.05). CONCLUSION: Rapid proliferation of rat HSCs occurs in response to AngII treatment, but is inhibited after AT1a receptor is blocked with the antagonist losartan.     

Effects of advanced glycation end products on renal fibrosis and oxidative stress in cultured NRK-49F cells

Background Advanced glycation end products （AGEs） play a critical role in the development of diabetic nephropathy. Reactive oxygen species （ROS） may play a critical role in AGEs induced growth factor expression. In this study, the effects of AGEs on transforming growth factor β1 （TGF-β1）, connective tissue growth factor （CTGF） and fibronectin （Fn） mRNA expression and oxidative stress in cultured NRK-49F cells were examined. Methods NRK-49F cells were incubated with medium containing different doses of AGEs （50, 100 or 200 μg/ml） for 24 hours, or with AGEs 100 μg/ml for different times （0, 12, 24 or 48 hours）. Cells in the serum-free medium or medium containing 25 mmol/L glucose were controls. Cells were treated with 25 mmol/L glucose and 100 μg/ml AGEs for 24 hours to determine the effects between AGEs and glucose. We clarified the role of antioxidant by pretreating cells with N-acetylcysteine （10 mmol/L）, ginkgo biloba extract （50 or 100 mg/L） for 24 hours and with 100 μg/ml AGEs for further 24 hours. Alamarblue dye assay was used to analyze cell growth; intracellular ROS generation was measured by flow cytometry; intracellular glutathione by fluorescence spectrophotometry; expressions of TGF-β1, CTGF and Fn mRNA by semiquantitative RT-PCR. Results AGEs significantly increased the expressions of TGF-β1, CTGF, Fn mRNA and intracellular ROS generation, and decreased the glutathion level in NRK-49F cells in dose- and time-dependent manners. High glucose and AGEs together significantly increased the expression of TGF-β1, CTGF and Fn mRNA, compared with AGEs and high glucose separately. Preincubation with N-acetylcysteine or ginkgo biloba extract increased GSH level, suppressed AGEs-induced oxidative stress and TGF-β1, CTGF and Fn mRNA overexpression. Conclusions AGEs can significantly increase expression of TGF-β1, CTGF, Fn mRNA in NRK-49F cells through enhancement of oxidative stress. The accumulation of AGEs may play a pivotal role in the pathogenesis of tubulointerstitial fibrosis in diabetic nephropathy. Suppression of AGEs induced TGF-β1, CTGF and Fn mRNA overexpression in renal fibroblasts through inhibition of oxidative stress may be a mechanism underlying effect of ginkgo biloba extract in diabetic nephropathy. In addition, antioxidant therapy may help prevent AGEs accumulation and its induced damage.     

Inhibition effect of small interfering RNA of connective tissue growth factor on the expression of vascular endothelial growth factor and connective tissue growth factor in cultured human peritoneal mesothelial cells

Background The peritoneum response to peritoneal dialysis can lead to fibrosis. The transforming growth factor β1 （TGF-β1 ） plays a key role in regulating tissue repair and remodelling after injury. Connective tissue growth factor （CTGF）, a downstream mediator of TGF-β1 inducing fibrosis, has been implicated in peritoneal fibrosis. Vascular endothelial growth factor （VEGF） plays a key role in angiogenesis that can hasten peritoneal fibrosis. In this study, we investigated the effect of small interfering RNA （siRNA） of CTGF by pRETRO-SUPER （PRS） retrovirus vector on the expression of CTGF and VEGF in human peritoneal mesothelial cells. Methods Retrovirus producing CTGF siRNA were constructed from the inverted oligonucleotides and transferred into packaging cell line PT67 with lipofectamine, and the virus supernatant was used to infect human peritoneal mesothelial cell （HPMC）. The cells were divided into seven groups： low glucose DMEM, low glucose DMEM ＋ TGF-β1 5 ng/ml, low glucose DMEM ＋ TGF-β1 5 ng/ml ＋ PRS-CTGF-siRNA1-4 and low glucose DMEM ＋ TGF-β1 5 ng/ml ＋ PRS. The expression of CTGF and VEGF were measured by semiquantitative RT-PCR and Western blot. Results Low levels of CTGF and VEGF were detected in confluent HPMCs. Following stimulation with TGF-β1 , the levels of CTGF and VEGF were significantly upregulated （P〈0.01）. Introduction of PRS-CTGF-siRNA1-4 resulted in the significant reduction of CTGF mRNA and protein, and VEGF mRNA （P〈0.01）, especially in groups PRS-CTGF-siRNA, and PRS-CTGF-siRNA4. The introduction of PRS void vector did not have these effects （P〉0.05）. Conclusions The expression of CTGF siRNA mediated by PRS retrovirus vector can effectively reduce the level of CTGF and VEGF induced by TGF-β1 in cultured HPMCs. This study may provide potential therapeutic strategies to prevent the peritoneal fibrosis.     

胃促生长素对人主动脉平滑肌细胞增殖及线粒体融合蛋白2表达的影响

目的 通过体外培养人主动脉平滑肌细胞(HASMCs),研究胃促生长素(ghrelin)对血管平滑肌细胞(VSMC)增殖及线粒体融合蛋白2(Mfn-2)表达的影响.方法 体外培养HASMCs,第4～6代细胞用于试验.给予不同浓度(10-9、10-8、10-7、10-6、10-5 mol/L)的ghrelin 或10-6 mol/L ghrelin不同时间(0、6、12、18、24 h)处理,用四甲基偶氮唑蓝比色(MMT)法观察其对HASMC增殖的影响.RT-PCR,Western blot方法检测不同处理方法对Mfn-2表达的影响.结果 10-7～10-5 mol/L的ghrelin可明显抑制HASMC增殖,浓度为10-6 mol/L抑制作用最为明显(P<0.01).ghrelin在6～24 h内均能明显抑制HASMC增殖,在24 h达最高峰(P<0.01).10-6 mol/L ghrelin能明显上调Mfn-2 mRNA和蛋白的表达(P<0.01).10-6 mol/L ghrelin在18 h上调Mfn-2 mRNA和蛋白表达的作用最为明显(P<0.01).结论 ghrelin可能通过上调Mfn-2的表达来抑制HASMC增殖.