内皮细胞Jagged1下调促进PDGF诱导的大鼠平滑肌细胞增殖迁移

目的:观察血管内皮Jagged1下调对血小板衍生的生长因子(platelet derived growth factor,PDGF)诱导平滑肌细胞增殖迁移的影响。方法:分离培养大鼠主动脉内皮和平滑肌细胞,将内皮接种于下室、平滑肌接种于上室建立细胞共培养体系,根据内皮是否行Jagged1小RNA干扰分为对照组、空载体组和Jagged1小RNA干扰组。用Western blot检测内皮     

辛伐他汀对血管平滑肌细胞增殖和迁移的影响

目的观察辛伐他汀对血管平滑肌细胞增殖、迁移及血管内皮生长因子表达的影响。方法体外培养大鼠原代血管平滑肌细胞,体内建立大鼠动脉粥样硬化血管损伤模型,分为正常对照组、动脉粥样硬化损伤组、低剂量和高剂量辛伐他汀组。4周后处死动物,酶法测定血脂水平,检测胸主动脉和左颈总动脉内膜/(内膜 中膜)比值,免疫组织化学和逆转录聚合酶链反应法检测血管内皮生长因子的表达。结果辛伐他汀对血管平滑肌细胞的增殖和迁移无双向调节作用。小剂量辛伐他汀对血管平滑肌细胞的增殖和迁移无促进作用,大剂量辛伐他汀抑制血管平滑肌细胞的增殖和迁移,且随着时间延长和浓度增加其抑制作用增强,这种作用不依赖辛伐他汀的调脂性。辛伐他汀能减少血管平滑肌细胞血管内皮生长因子的表达,且高浓度的辛伐他汀显著减少血管内皮生长因子的表达。结论辛伐他汀可能通过减少血管平滑肌细胞血管内皮生长因子的表达来抑制血管平滑肌细胞的增殖和迁移。     

辛伐他汀对支架置入后兔腹主动脉内膜增生的影响

目的 观察辛伐他汀对兔腹主动脉支架置入后内膜增殖的影响.方法 30只新西兰大白兔随机分为对照组和辛伐他汀治疗组.采用含1.5%胆固醇的高脂饮食加腹主动脉内皮剥脱术制作兔腹主动脉粥样硬化模型.内皮剥脱术后第12周实验组和对照组服用阿司匹林25 mg/d,氯吡格雷12.5 mg/d, 3 d后,分别行支架置入术.术后实验组继续服用辛伐他汀5 mg/d,服药至第30天处死动物,取腹主动脉含支架段血管,进行血管壁组织形态学变化观察和检测细胞周期抑制蛋白P27kip1、增殖细胞核抗原(PCNA)在各组的表达量的变化.结果 血管超声发现内皮剥脱术后第10周实验组和对照组腹主动脉均可见有不同程度的粥样硬化斑块和血管内狭窄.组织形态学观察发现服用辛伐他汀的实验组兔腹主动脉支架段内的血管内膜厚度(0.107±0.072 mm,与对照组0.133±0.047 mm比,P=0.006)、新生内膜面积(0.975±0.084 mm2,与对照组1.350±0.043 mm2比,P=0.001)均明显降低,且血管的狭窄程度较轻(20.460%±2.325%,与对照组31.020%±1.904%比,P=0.002).实验组兔腹主动脉支架段内的血管新生内膜中的血管平滑肌细胞(VSMC)的胞核P27kipl蛋白表达量明显升高(7.149±0.305,与对照组2.997±0.310比,t=9.551,P＜0.05),而血管新生内膜中VSMC的胞核PCNA表达量明显降低(着色强度IS为3.003±0.192, 与对照组着色强度IS 5.268±0.475比,t=4.423,P＜0.05).结论 辛伐他汀能明显抑制支架置入术后血管内膜增生.其机制可能为通过上调P27kip1蛋白表达量,使增殖标志物PCNA表达量降低,而对VSMC增殖周期起负调控作用,达到抑制VSMC增殖和新生内膜的增生.     

罗格列酮对大鼠胸主动脉球囊损伤后内皮再生和内膜增生的影响

目的探讨罗格列酮(rosiglitazone,RSG)对血管损伤后内皮再生和内膜增生的影响。方法制备大鼠胸主动脉球囊损伤模型,将SD大鼠随机分为RSG组、对照组和假手术组,于术后第7天和第14天处死动物。分别进行伊文思蓝染色观察内皮覆盖情况,细胞核增殖抗原(PCNA)免疫组化染色和组织形态学定量分析,并测量损伤后14 d时各组血清一氧化氮(NO)含量。结果RSG 7 d组和14 d组的再生内皮覆盖率分别为38.2%和75.2%,均较对照组(32.4%和60.4%)显著增加(P<0.05和P<0.01),且RSG 14 d组血清中的NO含量较对照组升高。球囊损伤后7 d内膜开始有少量增生,14 d时形成明显的新生内膜。RSG使损伤后14 d形成的新生内膜显著减少,内膜面积与中膜面积的比值(IA/MA)较对照组降低60.9%。与对照组比较,RSG 7 d组和14 d组新生内膜内的PCNA阳性表达指数均显著减少。结论RSG可以促进大鼠胸主动脉球囊损伤处的内皮再生,并减少新生内膜的形成。     

骨髓间充质干细胞对球囊损伤的大鼠颈总动脉内皮修复的影响

目的 研究骨髓间充质干细胞对球囊损伤的大鼠颈总动脉内皮修复的影响.方法 球囊损伤24只SD大鼠颈总动脉,建立动脉内皮损伤模型,随机分为:(1)治疗组12只SD大鼠,球囊损伤颈总动脉即刻注射1 mL骨髓间充质干细胞溶液;(2)对照组12只SD大鼠,球囊损伤颈总动脉即刻注射1 mL磷酸盐缓冲液.14 d及28 d后,取颈总动脉标本作组织病理切片,行苏木精伊红及血管内皮生长因子受体2、α-平滑肌肌动蛋白免疫组化染色.结果 用苏木精伊红染色观察新生内膜的厚度,14 d及28 d治疗组血管内膜增生均较对照组轻(14 d时0.57±0.06 cm比1.09±0.06 cm,P<0.05;28 d时0.43±0.09 cm比4.72±0.15 cm,P<0.05);用血管内皮生长因子受体-2免疫组化染色观察内皮化程度,治疗组血管内皮细胞覆盖程度高于对照组(14 d时70.8%±1.3%比20.4%±1.1%,P<0.05;28 d时90.2%±1.3%比10.7%±0.4%,P<0.05),治疗组可见血管内皮生长因子受体-2/5-溴脱氧尿核苷双阳性细胞约占血管内皮生长因子受体-2单阳性细胞的50%.α-平滑肌肌动蛋白免疫组化染色观察平滑肌细胞浸润积分,14 d时治疗组平滑肌细胞浸润1.5分,对照组2分;28 d时两组分别为1分和3分.结论 骨髓间充质干细胞可减轻新生内膜增生,加快损伤血管的内皮化进程,减少平滑肌细胞浸润,从而促进球囊损伤的大鼠颈总动脉内皮完整性修复.     

球囊损伤后血管内皮平滑肌细胞肿瘤抑制因子的表达及意义

目的观察球囊损伤后大鼠颈动脉血管平滑肌细胞肿瘤抑制因子(PHB)蛋白的表达变化。方法 SPF级SD雄性大鼠24只,随机分为对照组6只和损伤组18只。对照组颈动脉插管但不行球囊损伤,损伤组制作大鼠颈动脉损伤模型,分别于损伤后7、14、28 d各取6只大鼠,取血管标本,HE染色测定各组增殖血管内膜面积;分别采用免疫组化染色和Western blot法检测增殖血管平滑肌细胞中的PHB。结果正常血管内膜仅为一层扁平的内皮细胞,中层为呈梭形的平滑肌细胞。球囊损伤后7d,血管中层增厚,新生内膜形成,有4～6层细胞,损伤后14 d内膜层显著增厚,有8～10层细胞;损伤后28 d内膜层继续增厚。损伤组增殖血管内膜面积损伤后28 d>损伤后14 d>损伤后7 d>对照组,P均<0.05。正常血管平滑肌细胞中仅有少量PHB表达,增殖血管平滑肌细胞中的PHB在球囊损伤后7、14 d表达增加,28 d表达高峰,PHB表达损伤组损伤后28 d>损伤后14 d>损伤后7 d>对照组,P均<0.05。结论正常血管平滑肌细胞中有少量PHB蛋白表达,球囊损伤后增殖的血管内皮平滑肌细胞中PHB蛋白表达增加,可能与平滑肌细胞增殖、迁移有关。     

昆明山海棠及其提取物对兔血管球囊损伤后内膜增生的抑制作用

目的 探讨昆明山海棠(THH)及其提取物THW-4对兔血管球囊损伤后内膜增生的作用.方法 建立兔颈动脉损伤模型,采用THH中药灌胃及THH中药灌胃/THW-4局部灌注两种给药方式,分别观察用药14 d和28 d后药物对血管新生内膜形成及内皮修复的影响.结果 用药后14 d,增殖细胞核抗原(PCNA)免疫组织化学染色显示, THH灌胃组和联合用药组新生内膜中PCNA染色阳性细胞比率均明显少于对照组(17.68%±5.27%,6.60%±2.52%比40.37%±7.12%,P<0.01);伊文思蓝活体染色显示各组内皮修复差异不明显.用药后28 d血管壁定量组织形态学分析显示,THH灌胃组和联合用药组血管新生内膜面积及内膜面积与中膜面积比均显著低于对照组(2.95±0.65 mm2, 3.49±0.44 mm2比5.25±0.53 mm2;0.53±0.10,0.69±0.10比0.97±0.14,P均<0.01).结论 THH及THW-4可有效抑制血管球囊损伤后血管平滑肌细胞的增殖及新生内膜的形成.     

黄连素对血管平滑肌细胞增殖、大鼠颈动脉球囊损伤模型及PTEN基因表达的影响

目的:探讨黄连素对血管平滑肌细胞(VSMC)增殖、大鼠颈动脉球囊损伤后动脉新生内膜形成及损伤后再狭窄的影响,及其影响是否通过改变PTEN(第10q23染色体的抑癌基因)的表达来实现。方法:MTT法检测黄连素对主动脉VSMC增殖的影响,实时定量RT-PCR及Western blot法测定黄连素对VSMC PTEN在转录及蛋白水平表达的影响。建立颈动脉球囊损伤模型,观察黄连素对新生内膜形成及再狭窄的影响及血管组织表达PTEN的变化。结果:黄连素抑制大鼠主动脉VSMC的增殖,改善损伤血管新生内膜形成及再狭窄;上调PTEN表达,且与浓度呈正相关,200μmol/L黄连素干预VSMC效果最佳;球囊损伤模型再狭窄的预防经过术前、术后各2周的黄连素处理,较单纯术后黄连素处理效果更佳。结论:黄连素可能通过上调PTEN表达来抑制VSMC增殖与球囊损伤模型内膜的增生及损伤后再狭窄。     

几丁聚糖对大鼠颈动脉球囊损伤术后血管内膜增生的影响

目的研究几丁聚糖对大鼠颈动脉球囊损伤术后再狭窄的影响,并探讨其机制。方法60只SD大鼠分为几丁聚糖组和模型组各30只。复制大鼠颈动脉球囊损伤模型。几丁聚糖组在术前1周即开始每天一次灌胃几丁聚糖2g,并在术后继续给予至处死;模型组只建立模型但不予以任何处理。分别于手术后即刻(0d)、7d、14d、28d和35d,每组各处死大鼠6只。光镜下观察血管内膜损伤;运用图形分析系统检测增殖的内膜面积;α肌动蛋白免疫组织化学检测增殖内膜细胞的性质,血管内皮生长因子免疫组织化学标记血管内皮细胞明确损伤后血管内皮修复情况。结果模型复制成功53例,几丁聚糖组28例,模型组25例。手术后即刻见血管内膜完全剥脱,部分可见平滑肌细胞断裂。手术后7d可见内膜增生。模型组血管内膜在第28天增生达高峰,几丁聚糖组内膜增生在术后14d达到高峰。几丁聚糖组与模型组比较内膜增生程度差异有显著性(P均<0.05)。α肌动蛋白检测结果显示增殖的内膜细胞为血管平滑肌细胞。血管内皮生长因子检测结果显示几丁聚糖组在手术后14d血管完全再内皮化,而模型组手术后28d才完全再内皮化。结论几丁聚糖能预防大鼠颈动脉球囊损伤术后再狭窄,其机制可能与几丁聚糖促进血管再内皮化有关。     

雌激素对卵巢切除雌兔血管内膜损伤后血小板聚集与血管平滑 …

探讨不同剂量雌激素对切除卵巢的雌兔血管内膜损伤血小板聚集与血管平滑肌增殖的影响。方法 切除卵巢的成年雌性大白兔５０只，行主动脉球囊扩张术，造成血管内膜损伤实验模型，采用氚标记胸腺嘧啶脱氧核苷掺入测定雌激素对血管平滑肌细胞增生的影响，采用图像分析仪测定新生内膜增生面积及Ｂｏｒｎ比地测定雌激素对血小板聚集的影响。     

Ageing-exaggerated proliferation of vascular smooth muscle cells is related to attenuation of Jagged1 expression in endothelial cells

AIMS: Ageing has been shown to enhance neointima formation due to abnormal growth of vascular smooth muscular cells (VSMC), which is regulated by endothelial functions. The mechanism of how endothelium affects the growth of VSMC in the process remains unclear. We here examined the role of Jagged1, a regulator of cell growth. METHODS AND RESULTS: Male Sprague-Dawley rats at 3 (young) and 22 (old) months of age were subjected to a balloon catheter injury in the thoracic aorta. After 4 weeks, the neointima formation in the injured artery of old rats was more than that of young rats. Compared with the young rats, the increase in Jagged1 expression in the endothelium of old rats after the injury was delayed, weakened, and shortened, suggesting an impaired response of Jagged1 to the injury. In contrast, the increase in the expression of proliferating cell nuclear antigen in the neointima was more significant and maintained longer in old rats than in the young ones. Moreover, the expression of Jagged1 in the cultured arterial endothelial cells (EC) of old animals was less than those of the young ones, which promoted the Platelet-derived growth factor (PDGF)-induced growth and migration of the co-cultured VSMC. Furthermore, suppression of Jagged1 expression by a small interfering RNA in the EC of young rats reduced alpha-smooth muscle actin and calponin expression and also intensified the PDGF-increased growth and migration of the co-cultured VSMC. CONCLUSION: Ageing enhanced VSMC proliferation, at least in part, through impairing Jagged1 expression in the EC after vascular injury.     

Jagged1基因沉默对人胰腺癌细胞SW1990和PANC1血管相关因子分泌及迁移能力的影响

目的 以RNA干扰技术靶向沉默人胰腺癌细胞株Jagged1基因,观察细胞VEGF、Angiopoietin2、bFGF、MMP9的分泌及细胞迁移能力的变化.方法 应用靶向Jagged1的siRNA、对照siRNA(c-siRNA)转染人胰腺癌细胞株SW1990和PANC1,实时PCR法和蛋白质印迹法检测细胞Jagged1 mRNA和蛋白的表达,ELISA法检测细胞培养上清中VEGF、angiopoietin2、bFGF、MMP9的分泌量,Transwell小室观察细胞的迁移能力.结果 SW1990和PANC1细胞均高表达Jagged1基因.15 nmol/L Jagged1 siRNA转染胰腺癌细胞72 h后,SW1990、PANC1细胞的Jagged1 mRNA表达被抑制,分别为c-siRNA组的(59.62 ±2.75)％和(76.96 ±6.16)％,Jagged1蛋白表达几乎完全被抑制.SW1990、PANC1细胞的VEGF分泌量均较c-siRNA组显著减少[(867.93±58.69) pg/ml比(1516.24±37.58)pg/ml,(951.13±120.49) pg/ml比(1413.68±33.56) pg/ml,P＜0.05],但angiopoietin2、bFGF、MMP9蛋白分泌无明显变化.另外,Jagged1 siRNA转染后,SW1990细胞VEGF mRNA表达水平为c-siRNA组的(52.26 ±4.85)％ (P＜ 0.05);PANCI细胞为c-siRNA组的(59.75±4.91)％(P＜0.05).转染后的SW1990和PANC1细胞的穿膜细胞数分别为(65.25±5.56)、(57.50±8.58)个,较c-siRNA组的( 122.25±11.09)、(112.00±12.52)个显著减少(P＜0.05).结论 人胰腺癌细胞高表达Jagged1,沉默Jagged1基因可明显抑制人胰腺癌细胞VEGF的产生和分泌,并且可降低癌细胞的体外迁移能力.     

紫杉醇水蛭素复合物对兔血管平滑肌细胞和内皮细胞增殖与迁移的影响

目的观察不同浓度紫杉醇水蛭素复合物对兔血管平滑肌细胞（smooth musele cell,SMC）和内皮细胞（endothelial cell,EC）增生、迁移的影响。方法培养兔血管SMC和EC,建立细胞共培养体系,模拟紫杉醇水蛭素复合物对血管SMC及EC的作用方式,观察不同浓度紫杉醇水蛭素复合物对兔血管SMC及EC的DNA合成、增殖细胞核抗原（proliferating cell nuclear antigen,PCNA）蛋白表达的影响,测定不同浓度紫杉醇水蛭素复合物对血管SMC及EC的迁移率。结果溶剂对照组SMC及EC的氚-胸腺嘧啶脱氧核苷（^3H-TdR）掺入、PCNA蛋白表达、迁移与空白对照组相比差异均无显著性。大、中、小剂量紫杉醇水蛭素复合物呈浓度依赖地抑制SMC的^3H—TdR掺入、PCNA蛋白表达和迁移（n=6,P〈0．05）;在大、中剂量之间,紫杉醇水蛭素复合物呈浓度依赖地抑制EC的^3H—TdR掺入、PCNA蛋白表达和迁移（n=6,P〈0．05）;但在小剂量组紫杉醇水蛭素复合物对EC的^3H—TdR掺入、PCNA蛋白表达和迁移有抑制倾向,但与空白对照组相比差异均无显著性。结论小剂量的紫杉醇水蛭素复合物可显著抑制兔血管SMC的增生与迁移,但抑制EC的增生与迁移不明显。     

雷公藤多甙、藻酸双酯钠对大鼠受损动脉内膜增生的影响

31只大鼠行胸主动脉内皮剥脱术,随机分为对照组10只、雷公藤多甙组10只(9.4 mg/kg/d)和藻酸双酯钠组11只(30mg/kg/d).后两组于术前6天开始喂药.于术后14天观察各组大鼠胸主动脉新生内膜面积、内膜与中膜面积比、新生内膜覆盖率、~3H-TdR参入量.证明雷公藤多甙能显著抑制受损动脉内膜增生(P<0.001),而藻酸双酯钠则无此作用.     

原发性病理性十二指肠胃反流患者的胃电活动和胃排空研究

目的 通过分析原发性病理性十二指肠胃反流(DGR)患者胆汁反流程度与体表胃电节律变化以及胃排空运动之间的关系,探讨原发性病理性DGR致病因素.方法 收集2007年1月至2008年4月青岛市立医院门诊诊断为原发性病理性DGR患者58例(DGR组)和健康者21例(对照组)进行24 h胃内胆红素监测、胃镜、胃电图和胃排空检测,分析胃电参数及其与胃排空、胆汁反流和Hp之间的关系.结果 ①原发性病理性DGR患者的餐前及餐后胃电慢波主频率[(1.94±0.04) cpm比(2.93±0.07) cpm;(2.12±0.03) cpm比(3.35±0.05) cpm]、餐前及餐后正常胃电慢波百分比(74.46％±0.56％比85.55％±1.06％;63.97％±0.64％比86.13％±1.49％)、餐前/餐后功率比(PR)(1.68±0.02比2.75±0.09)均低于对照组(P＜0.05).原发性病理性DGR患者的餐前及餐后胃动过缓百分比(18.04％±0.36％比7.76％±0.78％;23.73％±0.91％比8.47％±0.55％)、餐前及餐后胃动过速百分比(8.93％±0.26％比5.75％±0.66％;13.02％±0.40％比7.66％±0.27％)均高于对照组(P＜0.05).②高反流组患者的餐前及餐后胃电慢波主频率[(1.68±0.07) cpm比(2.13±0.07) cpm;(2.18±0.09)cpm比(2.76±0.06)]、餐前及餐后正常胃电慢波百分比(69.71％±0.43％比80.35％±0.68％;56.36％±0.85％比72.34％±0.80％)、餐前/餐后功率比(PR)(1.47±0.04比2.02±0.04)均低于低反流组(P＜0.05).高反流组患者的餐前及餐后胃动过缓百分比(22.94％±0.68％比13.47％±0.61％;29.61％±1.14％比17.55％±0.51％)、餐前及餐后胃动过速百分比(9.94％±0.54％比7.02％±0.42％;17.04％±0.70％比10.71％±0.20％)均高于低反流组(P＜0.05);③Hp阳性组和Hp阴性组餐前、餐后各胃电参数差异均无统计学意义(P＞0.05);④DGR患者胃钡条排空者明显低于对照组(37.9％比90.5％,P＜0.05).DGR组胃排空延迟较对照组明显增多,两者比较差异,(60.3％比9.5％,P＜0.05).高反流组与低反流组比较胃排空延迟率差异无统计学意义(69.0％比51.7％,P＞0.05).结论 原发性病理性DGR患者存在胃电节律紊乱和胃运动功能障碍,这可能是病理性DGR的一个重要原因.     

Age-related pseudocapillarization of the liver sinusoidal endothelium impairs the hepatic clearance of acetaminophen in rats

We investigated the effect of age-related pseudocapillarization of the liver sinusoidal endothelium on the hepatic disposition of acetaminophen. The multiple indicator dilution technique assessed the hepatic disposition of tracer (14)C-acetaminophen and reference markers in isolated perfused livers of young (n = 11) and old (n = 12) rats. Electron microscopy confirmed defenestration of the sinusoidal endothelium in old rats compared with young rats. Acetaminophen recovery following a single pass through the liver was significantly increased in old rats (0.64 ± 0.04, old; 0.59 ± 0.05, young; p < .05). In old age, there was significant reduction of the intercompartmental rate constant k(1) (0.34 ± 0.10 s(-1), old; 0.61 ± 0.38 s(-1), young; p < .05) and the permeability-surface area product for the transfer of acetaminophen across the sinusoidal endothelium (0.034 ± 0.006 mL/s/g, old; 0.048 ± 0.014 mL/s/g, young; p < .005). There was no difference in k(3), the measure of sequestration of acetaminophen that reflects enzyme activity. Age-related pseudocapillarization of the liver sinusoid resulted in increased acetaminophen recovery and decreased transfer of acetaminophen into the liver.     

舒心益脉煎对气滞血瘀型大鼠动脉内膜损伤后细胞凋亡及基因蛋白产物的影响

探讨气滞血瘀型大鼠胸主动脉内膜剥脱后内膜增生中，舒心益脉煎对血管平滑肌细胞凋亡及相关基因Fas抗原和Fas配体的影响。将58只大鼠随机分为假且10只，舒心益脉煎组和对照组各24只。后两组大鼠行胸主动脉内膜剥脱术，舒心益脉煎组动物于术前7d至术后14d每日接受舒心益脉煎治疗。术后14d处死动物，用免疫组织化学法测定Fas抗原与Fas配体在血管中的表达，原位末端标记法测定凋亡细胞。术后14d血管新生内膜中有平滑肌细胞凋亡；舒心益脉煎显著增加新生内膜中Fas抗原与Fas配体的表达，增加血管平滑肌细胞凋亡，减少新生内膜面积。说明舒心益脉煎可能通过Fas系统调节动脉血管内皮损伤修复过程中血管平滑肌细胞凋亡，从而抑制新生内膜形成。     

Vascular smooth muscle cell growth kinetics in vivo in aged rats.

Age is a risk factor in the development of atherosclerosis. In this study we investigated the hypothesis that proliferation of vascular smooth muscle cells (SMCs), an integral part of atherosclerotic plaque formation, changes with age. SMC growth kinetics of old rats (21-24 months) were compared to those of young adult rats (3-4 months). Rat aortas were denuded of their endothelium and the animals were killed after [3H]thymidine and Evans blue injections at 0-28 days after denudation. Incorporation of [3H]thymidine into SMC peaked in the young animals by day 2, whereas the older animals responded to endothelial removal with greater incorporation at day 2 and a more sustained rate of incorporation peaking at day 4. The [3H]thymidine incorporation curves decreased sharply from their peaks at 2 and 4 days, respectively, and paralleled each other after day 7. [3H]Thymidine uptake reflected the subsequent SMC intimal growth as measured morphometrically, with old animals showing greater numbers of intimal SMC than did the younger animals. The difference in response of SMC to injury with age suggests that aging produces a change in the vascular SMC that enhances proliferation. This change in response implies that the more pronounced atherosclerotic plaque growth seen with aging may be a result of an age-related increase in response to injury rather than merely the accumulation of time-related intimal change.     

In vivo gene transfer: prevention of neointima formation by inhibition of mitogen-activated protein kinase kinase

Background The mitogenactivated protein kinase kinase (MAPKK) is a protein downstream ras which is rapidly activated in cells stimulated with various extracellular signals. These proteins are believed to play a pivotal role in integrating and transmitting transmembrane signals required for cell growth.Methods and Results To study the effect of inhibition of MAPKK on smooth muscle cell (SMC) proliferationin vivo after vascular injury, we performed experimental balloon angioplasty using the standard Clowes technique in male Wistar rats 14-weeks old. The animals did not receive any treatment after vascular injury (N=6) or were randomly assigned to receive, after balloon injury, a 30% (w/v) pluronic gel solution applied to the injured carotid artery, containing respectively: 1) no plasmid DNA (n=10); 2) RSV-lacZ (encoding the -galactosidase gene) as control gene without effects on SMC proliferation (n=10); 3) Tg-CAT (encoding cloramphenicol acetyl-transferase gene under the control of thyreoglobulin promoter) as an additional control gene without effects on SMC proliferation (n=7); 4) a negative mutant of Mitogen-Activated Protein Kinase Kinase (MAPKK) (n=13). Fourteen days after vascular injury, carotid arteries were removed and cross sections were cut and stained with hematoxylin/eosin. Morphometric analysis demonstrated, in the MAPKK-treated rats, a significant reduction of both neointima (0.096±0.018 mm² vs. 0.184±0.019 mm², p<0.01) and neointima/media ratio (0.603±0.103 vs. 1.147±0.161, p<0.01) compared to control DNA.Conclusions The inhibition of MAPKK, by a dominant inhibitor mutant gene, prevents the SMC proliferation after vascular injuryin vivo.     

Matrix metalloproteinase-9 is necessary for the regulation of smooth muscle cell replication and migration after arterial injury

Matrix metalloproteinases (MMPs) and, in particular, MMP-9 are important for smooth muscle cell (SMC) migration into the intima. In this study, we sought to determine whether MMP-9 is critical for SMC migration and for the formation of a neointima by using mice in which the gene was deleted (MMP-9(-/-) mice). A denuding injury to the arteries of wild-type mice promoted the migration of medial SMCs into the neointima at 6 days, and a large neointimal lesion was observed after 28 days. In wild-type arteries, medial SMC replication was approximately 8% at day 4, 6% at day 6, and 4% at day 8 and had further decreased to 1% at day 14. Intimal cell replication was 65% at 8 days and had decreased to approximately 10% at 14 days after injury. In MMP-9(-/-) arteries, SMC replication was significantly lower at day 8. In addition, SMC migration and arterial lesion growth were significantly impaired in MMP-9(-/-) arteries. SMCs, isolated from MMP-9(-/-) mouse arteries, showed an impairment of migration and replication in vitro. Thus, our present data indicate that MMP-9 is critical for the development of arterial lesions by regulating both SMC migration and proliferation.