肝细胞生长因子激活胶原降解途径逆转心肌纤维化

Objective To study the effects of hepatocyte growth factor (HGF) on angiotensin Ⅱ(Ang Ⅱ )-induced synthesis and degradation of cardiac fibroblast collagen in neonatal mice.Methods Cardiac fibroblasts (CFs) of neonatal Sprague-Dawley (SD) rats were isolated by differential adhesion, and were identified by immunocytochemistry.The cells were assigned to normal control group (group C) , 10-6 mol/L Ang Ⅱ group (group A), 10μg/L HGF + 10-6 mol/L Ang Ⅱ group (group H1) and 100μg/L HGF +10-6 mol/L Ang Ⅱ group (group H2).All the groups were treated for 48 h.Hydroxyproline assay was used to determine the collagen protein level.RT-PCR was used to detect the expression of ColⅠ, ColⅢ, matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-l) mRNA, and Western blotting was employed to measure Col I protein.In addition, MMP-1 activity was evaluated by collagenase Ⅰ activity assay kit.Results After intervention for 48 h, the collagen protein levels in groups A and H1 were significantly higher compared with group C [ (39.08±2.71) mg/L vs (37.45±4.22) mg/L vs (23.73 ±±1.62) mg/L, all P＜0.05] and the collagen protein level in group H2 [(26.03±3.04) mg/L] was lower than those of groups A and Hl(P＜0.05), but was not statistically different from group C.The expression levels of Col Ⅰ ,Col M and TIMP-1 showed an order of group A＞group HI＞group H2> group C (all P＜0.05), and for MMP-1 mRNA, group A ＜ group H1 ＜ group H2 ＜ group C (all P＜0.05).The levels of Col I protein expression showed an order of group A＞group HI＞group H2＞group C (89.90±4.29 vs 68.21?1.43 vs 36.08?.8 vs 30.14?.36, all P＜0.05).The expression and activity of MMP-1 mRNA in group A and H1 were obviously lower than those in group C (all P＜0.05), while group H2 were comparable to group C in these data.Conclusion HGF re-regulates MMP-1-TIMP-1 balance and ameliorates myocardiac fibrosis mainly by activating collagen degradation.     

血管紧张素Ⅱ刺激肥大心肌细胞和心肌成纤维细胞核酸蛋白质及胶原合成

本实验用压力（ＰＯ）和容量超负荷（ＶＯ）性分离的肥大心肌细胞（ＭＣ）及培养的心肌成纤维细胞（Ｆｂｓ），就血管紧张素（Ａｎｇ）Ⅱ对其￣３Ｈ－Ｌｅｕ，￣１４Ｃ－ＵＲ，￣３Ｈ－ＴｄＲ和￣３Ｈ－ｐｔｏ掺入率的影响进行了对比研究。发现尽管ＡｎｇⅡ可提高正常和两种肥大ＭＣ的￣３Ｈ－Ｌｅｕ和￣１４Ｃ－ＵＲ掺入率，但肥大ＭＣ增加幅度显著高于假手术对照（ＳＯ）组，尤其以ＶＯ组最为明显（Ｐ＜０．０５ｖｓＰＯ）。相反，ＰＯ组ＦｂＳ的￣３Ｈ－ＴｄＲ，￣１４Ｃ－ＵＲ和￣３Ｈ－Ｐｒｏ掺入率增加幅度又显著高于ＳＯ和ＶＯ组。除￣３Ｈ－Ｐｔｏ外，ＶＯ组的￣３Ｈ－ＴｄＲ及￣１４Ｃ－ＵＲ掺入率与ＳＯ组相比差异无显著性。表明ＡｎｇⅡ对两种肥大心肌的ＭＣ和Ｆｂｓ的核酸、蛋白质及胶原合成的促进作用存在明显差异。提示：ＡｎｇⅡ的这种作用可能是导致压力和容量超负荷性心肌肥大时，心肌实质细胞与胶原增生出现不同步发展的主要和直接原因之一。     

TGF—β1和AngⅡ的相互作用在心肌纤维化中的意义

心肌纤维化(MF)是高血压左室重构的主要表现之一,TGF-β1和AngⅡ是这一过程中的重要生物活性因子,AngⅡ通过血管紧张素Ⅱ-1型(ATi)受体对TGF-β1合成和释放的刺激,增加TGF-β1的表达和促进纤维的发生;TGF-β1也上调Ⅰ型、Ⅲ型胶原合成并抑制胶原酶的释放;两者相互作用,共同促进MF的发生.多种药物可对TGF-β1的表达产生抑制,AT1受体拮抗剂、血管紧张素转换酶抑制剂和TGF-β拮抗剂在降低TG-β1表达和减轻MF方面显示良好作用.     

Ang-Ⅱ对缺血缺氧性心肌胶原代谢的影响

目的：探讨缺血缺氧性心肌损伤过程中血管紧张素－Ⅱ（Ａｎｇ－Ⅱ）与心肌胶原代谢的关系。方法：用异丙基肾上腺素（ＩＳＰ）注射大鼠,造成心肌缺血缺氧和心肌坏死模型,检测血清内ＧＯＴ、ＣＫ、ＬＤＨ、ＨＢＤＨ（羟丁酸脱氢酶）的活性,并检测心肌组织内血管紧张素－Ⅰ转换酶（ＡＣＥ）、血管紧张素－Ⅱ（Ａｎｇ－Ⅱ）和心肌胶原含量变化,观察细胞外间质效应细胞增殖情况。结果：注射ＩＳＰ后,血清ＧＯＴ、ＣＫ、ＬＤＨ、ＨＢＤＨ活性增加,心肌匀浆内ＡＣＥ、Ａｎｇ－Ⅱ含量上升,并发现在ＡＣＥ、Ａｎｇ－Ⅱ升高的同时有成纤维细胞的增生,以后心肌胶原含量明显升高。结论：心肌缺血缺氧后,心肌局部合成释放ＡＣＥ、Ａｎｇ－Ⅱ增加,使心肌成纤维细胞增殖和合成胶原能力增强,出现心肌胶原含量的增加。说明Ａｎｇ－Ⅱ是心肌间质胶原反应的一个信号分子     

肥厚心肌胶原及基质金属蛋白酶的活性变化

探讨压力负荷增高性心肌肥厚时心肌胶原网络及心肌细胞外基质金属蛋白酶（ ＭＭＰｓ）活性的变化。腹主动 脉部分结扎术致大鼠压力负荷增高性心肌肥厚,ＶＧ染色和图像处理观察心肌胶原网络,酶谱法（Ｚｙｍｏｇｒａｐｈｙ）测定 心肌ＭＭＰｓ活性。结果：手术组大鼠术后２周即出现明显心肌肥厚,术后４周左室肥厚程度进一步加重。与假手术组 比较,左室心肌总胶原容积百分比（ＣＶＥ－Ｔ）于术后２周即增高（Ｐ＜０．０５）,术后４、８周大鼠ＣＶＦ－Ｔ和无小血管视野 ＣＶＦ（ＣＶＦ－ＮＶ）均明显增高（Ｐ＜０．０１）,手术组大鼠左室心肌组织ＭＭＰ－１活性明显低于相应假手术大鼠,但经胰蛋 白酶激活后其活性反而高于假手术大鼠。结论：压力负荷增高性心肌肥厚时伴有心肌胶原网络的重构,心肌组织内 ＭＭＰ－１活性调节异常可能与心肌胶原网络重构的形成有关。     

容量和压力负荷时心肌胶原增生与心肌血管紧张素Ⅱ的关系

对于机械负荷，尤其是容量负荷增加时，心肌胶原发生何种改变以及其机制如何，日前尚不十分清楚。本实验采用放射免疫及生化等方法，就大鼠动－静脉瘘和主动脉狭窄时，心肌和血浆血管紧张素Ⅱ含量、心肌胶原总量、含量及Ⅰ／Ⅲ型胶原比值的变化进行初步研究。     

运动对糖尿病心肌纤维化大鼠心肌Ⅰ、Ⅲ型胶原及血管紧张素Ⅱ/转化生长因子β1/Smad2通路的影响

背景:近年的研究发现运动能够改善2型糖尿病大鼠的心肌纤维化.目的:通过游泳运动干预糖尿病心肌纤维化动物模型,探讨血管紧张素Ⅱ/转化生长因子β1/Smad2信号通路及其下游因子在糖尿病心肌纤维化过程中的调控作用.方法:将40只雄性SD大鼠随机分为2组,其中10只正常饲养(空白对照组),另30只采用高糖高脂饲料+一次性注射...     

血管紧张素Ⅱ在心肌纤维化形成中的作用

心脏是由心肌细胞和几种非心肌细胞(成纤维细胞、平滑肌细胞和内皮细胞)构成的,非心肌细胞约占心脏细胞总数的三分之二,其中90%以上是成纤维细胞,它是合成和分泌细胞外基质的主要细胞.虽然婴儿出生后心肌细胞立即丧失增殖能力,但非心肌细胞仍然增殖,甚至在成人心脏也如此….心肌纤维化有多种分型,大多根据有无心肌细胞坏死和瘢痕出现,而分为修复性心肌纤维化和反应性心肌纤维化.在心肌纤维化的发生发展过程中,血管紧张素Ⅱ(AngⅡ)的作用是非常重要的.     

SHR心脏肥厚对心肌胶原及血管紧张素Ⅱ含量的变化

采用病理学及放射免疫方法检测 16、2 4和 32周龄自发性高血压大鼠 (SHR)心肌胶原容积分数 (CVF)和心肌血管周围胶原面积 (PVCA)、心脏肥厚指标及血浆和组织血管紧张素Ⅱ (AngⅡ )浓度 ,并以同龄Wister大鼠作对照 ,以探讨SHR心脏肥厚进展阶段心肌纤维化、心脏重构、血浆和组织血管紧张素Ⅱ浓度及其相互关系。结果显示各组SHR收缩压明显增高、心脏肥厚指标心脏重量 (HW )、左室重量 (LVW)、左室重量指数 (LVW BW)显著增加 ,血浆、心肌组织AngⅡ浓度明显增高 ;2 4、32周龄SHR的CVF和PVCA显著增加 ;SHR心肌组织AngⅡ浓度与CVF呈显著正相关。结果表明心肌纤维化可能参与SHR代偿性心脏肥厚阶段心脏重构病理过程 ,组织AngⅡ可能是导致SHR代偿性心脏肥厚阶段心肌纤维化的重要机制之一     

SHR心脏肥厚对心肌胶原及血浆紧张素Ⅱ含量的变化

采用病理学及放射免疫方法检测16、24和32周龄自发性高血压大鼠（SHR）心肌胶原容积分数（CVF）和心肌血管周围胶原面积（PVCA）、心脏肥厚指标及血浆和组织血管紧张素Ⅱ（AngⅡ）浓度,并以同龄Wister大鼠作对照,以探讨SHR心脏肥厚进展阶段心肌纤维化、心脏重构、血浆和组织血管紧张素Ⅱ浓度及其相互关系。结果显示,各组SHR收缩压明显增高、心脏肥厚指标心脏重量（HW）、左室重量（LVW）、左室重量指数（LVW／BW）显著增加,血浆、心肌组织AngⅡ浓度明显增高;24、32周龄SHR的CVF和PVCA显著增加;SHR心肌组织AngⅡ浓度与CVF呈显著正相关。结果表明心肌纤维化可能参与SHR代偿性心脏肥厚阶段心脏重构病理过程,组织AngⅡ可能是导致SHR代偿性心脏肥厚阶段心肌纤维化的重要机制之一。     

PLGF参与Ang II诱导的心脏成纤维细胞激活

 目的：探讨胎盘生长因子（PLGF）在血管紧张素II（Ang II）激活心脏成纤维细胞(CFs)中的表达及其作用。方法：原代分离培养并鉴定新生SD大鼠CFs。蛋白免疫印迹检测α-平滑肌肌动蛋白（α-SMA）、PLGF和磷酸化ERK1/2(p-ERK1/2),免疫荧光观察α-SMA的表达,WST-1法检测细胞增殖,RT-PCR检测PLGF、I型和III型胶原蛋白的mRNA表达水平。结果：(1)Ang II组PLGF mRNA 表达明显高于对照组（P<0．01),联用替米沙坦后,PLGF mRNA表达水平下降;Ang  II组PLGF蛋白表达水平高于对照组（P<0.05); (2)PLGF诱导CFs增殖及α-SMA蛋白表达增加（P<0.05）;PLGF干预CFs 60 min后,p-ERK1/2蛋白水平表达明显高于对照组（P<0.01);(3)Ang II+anti-PLGF组与Ang II组比较,细胞增殖和α-SMA蛋白表达水平下降（P<0.05）,I型和III型胶原蛋白mRNA表达水平亦下调（P<0.05）。结论：PLGF可能参与Ang II诱导的CFs增殖和纤维化过程。     

肝细胞生长因子抑制MRC-5成纤维细胞所致的纤维化作用

本研究采用人胎儿肺来源的成纤维细胞株MRC－5，作为体外研究肝细胞生长因子（HGF）抗组织纤维化的模型。成纤维细胞MRC－5被转化生长因子β1（TGF－β1）转化为肌成纤维细胞后，应用外源人重组HGF修饰细胞，检测细胞中分子表达水平的变化。研究发现，TGF－β1在诱导成纤维细胞株MRC－5转化为肌成纤维细胞的同时，上调HGF受体/c-Met在肌成纤维细胞中的表达。而且，应用外源人重组HGF修饰细胞后，内源性TGF－β1的表达水平被降低，内源性HGF的表达水平上调，基质金属蛋白酶I（MMP－I）mRNA表达增加，从而加速了细胞外基质主要成分－胶原蛋白I[Col(I)]的水解。结果显示在组织纤维经过程中，HGF通过其受体c-Met直接作用于肌成纤维细胞，抑制细胞内TGF－β1的表达，在一定程度上抑制组织纤维化的发生和发展。研究中我们还发现，肝素结合表皮生长因子样生长因子（HB－EGF）上调肌成纤维细胞中HGF的表达，是其抑制肌成纤维细胞形成、抑制组织纤维化的可能机制之一。     

肝细胞生长因子拮抗放线菌素D诱导的肝细胞凋亡及机制探讨

目的： 探讨肝细胞生长因子（HGF）对放线菌素D (ActD)诱导HL7702肝细胞凋亡的拮抗作用及可能机制。 方法： 本实验采用HL7702正常人肝细胞株，MTT法检测ActD对肝细胞存活力的影响；Hoechst33342进行凋亡形态学染色；DNA凝胶电泳及流式细胞仪检测细胞凋亡数量；Western blotting方法检测细胞总Akt及磷酸化Akt蛋白的表达。 结果： ActD可以诱导HL7702肝细胞凋亡，其浓度在0.25-8 mg/L范围内呈现剂量效应关系；PI3K特异性抑制剂wortmannin能够增强ActD诱导的肝细胞凋亡作用；肝细胞生长因子(HGF)对ActD诱导的肝细胞凋亡有拮抗作用，在一定剂量范围内呈现剂量效应关系；并且HGF能够激活PI3K/Akt信号转导途径；进一步用wortmannin阻断PI3K/Akt信号途径后，HGF的拮抗凋亡作用被抑制。 结论： 一定剂量的ActD可以诱导肝细胞凋亡；wortmannin能够增强ActD诱导肝细胞凋亡的作用；HGF对ActD诱导的这种细胞凋亡有明显的拮抗作用，并且HGF的抗凋亡作用与其激活细胞内PI3K/Akt信号转导通路有关。     

Effects of hepatocyte growth factor on collagen synthesis and matrix metalloproteinase production in keloids

Keloids are pathologic proliferations of the dermal layer of the skin resulting from excessive collagen production and deposition. Hepatocyte growth factor (HGF) increases the expression of matrix metalloproteinase (MMP)-1 and suppresses collagen synthesis to modulate extracellular matrix turnover. To investigate the anti-fibrotic effects of HGF, we examine the mRNA expression of collagen types I and III and matrix metalloproteinase (MMP-1, MMP-3) on human dermal fibroblast (HDF) cell lines and keloid fibroblasts (KFs, n = 5) after adding various amount of HGF protein. We also evaluated the enzymatic activity of MMP-2, MMP-9 by zymograghy. In HDFs treated with TGF-β1 and HGF protein simultaneously, both type I and III collagen mRNA expression significantly decreased (P < 0.05). Expression of MMP-1, MMP-3 mRNA also decreased. However, the mRNA expression of MMP-1, MMP-3 significantly increased in KFs with increasing amount of HGF in dose dependent manner (P < 0.05). The enzymatic activities of MMP-2 increased with increasing HGF protein in a dose-dependent manner. However, the enzymatic activity of MMP-9 did not change. These results suggest that the anti-fibrotic effects of HGF may have therapeutic effects on keloids by reversing pathologic fibrosis.     

Hepatocyte growth factor suppresses ischemic cerebral edema in rats with microsphere embolism

The present study was aimed at determining whether human recombinant hepatocyte growth factor (HGF) ameliorates cerebral edema induced by microsphere embolism (ME). Rats were injected with 700 microspheres (48 microm in diameter). Continuous administration of HGF at 13 microg/3 days/animal into the right ventricle was started from 10 min after embolism to the end of the experiment by using an osmotic pump. On day 3 after the ME, the rats were anesthetized, and their brains were perfused with an isotonic mannitol solution to eliminate constituents in the vascular and extracellular spaces. Thereafter, tissue water and cation contents were determined. A significant increase in tissue water content of the right hemisphere by ME was seen. This ME-induced increase in water content was associated with increases in tissue sodium and calcium ion contents and decreases in tissue potassium and magnesium ion contents of the right hemisphere. The treatment of the animal with HGF suppressed the increases in water and sodium and calcium ion contents, but not the decreases in potassium and magnesium ion contents. These results suggest that HGF suppresses the formation of ischemic cerebral edema provoked intracellularly in rats with ME.     

肝细胞生长因子和类胰岛素样生长因子对心肌干细胞的诱导作用

目的探讨肝细胞生长因子(HGF)和类胰岛素样生长因子(IGF1)在外能否诱导心肌干细胞(CSCs)发生增殖并向心肌细胞定向分化。方法组织贴块法分离培养心肌干细胞,免疫荧光技术鉴定c-kit和CD34表达,流式细胞仪分选纯化c-kit+细胞,CFDA SE荧光探针示踪培养检测细胞增殖特征。实验分为单纯心肌干细胞组和与心肌共培养组,分别用HGF和IGF1干预,倒置显微镜观察细胞不同时期数量与形态的变化,活细胞工作站观察CFDA SE示踪剂荧光强弱,采集图像,进行统计学分析。免疫荧光技术检测Nkx2.5、心肌肌钙蛋白T(cTnT)的表达。结果单纯心肌干细胞组,生长因子刺激后心肌干细胞数量与形态均无明显变化。与心肌共培养组,细胞均发生增殖与形态变化,Nkx2.5、cTnT阳性表达,有个别心肌干细胞分化为自发搏动的心肌细胞。结论心肌干细胞与心肌细胞共培养条件下,HGF和IGF1能够促进心肌干细胞增殖,联合作用能够诱导心肌干细胞向心肌细胞分化。     

Effect of hepatocyte growth factor and angiotensin II on rat cardiomyocyte hypertrophy

Angiotensin II (Ang II) plays an important role in cardiomyocyte hypertrophy. The combined effect of hepatocyte growth factor (HGF) and Ang II on cardiomyocytes is unknown. The present study was designed to determine the effect of HGF on cardiomyocyte hypertrophy and to explore the combined effect of HGF and Ang II on cardiomyocyte hypertrophy. Primary cardiomyocytes were isolated from neonatal rat hearts and cultured in vitro. Cells were treated with Ang II (1 µM) alone, HGF (10 ng/mL) alone, and Ang II (1 µM) plus HGF (10 ng/mL) for 24, 48, and 72 h. The amount of [³H]-leucine incorporation was then measured to evaluate protein synthesis. The mRNA levels of β-myosin heavy chain and atrial natriuretic factor were determined by real-time PCR to evaluate the presence of fetal phenotypes of gene expression. The cell size of cardiomyocytes was also studied. Ang II (1 µM) increased cardiomyocyte hypertrophy. Similar to Ang II, treatment with 1 µM HGF promoted cardiomyocyte hypertrophy. Moreover, the combination of 1 µM Ang II and 10 ng/mL HGF clearly induced a combined pro-hypertrophy effect on cardiomyocytes. The present study demonstrates for the first time a novel, combined effect of HGF and Ang II in promoting cardiomyocyte hypertrophy.