大鼠肝卵圆细胞与肝星状细胞在2-AAF/PH模型中的增殖及关系研究

目的 研究大鼠肝卵圆细胞与肝星状细胞增殖过程中关系,探讨肝星状细胞(HSCs)对卵圆细胞增殖分化的调控作用.方法 利用2-乙酰氨基芴/部分肝切除(2-AAF/PH)建立大鼠肝卵圆细胞增殖模型,对术后不同时间点的肝组织标本进行常规组织学观察,并用卵圆细胞标志物OV-6和HSCs激活标志物desmin进行免疫组化染色和免疫荧光双标,对阳性细胞进行半定量计数并分析两者相关性.结果 PH后第2天,门静脉区域开始出现小管样结构的卵圆细胞和HSCs增殖;PH后第4～6天,HSCs形成网格状伴随卵圆细胞迅速增殖,向肝实质内侵入;PH后第9天,HSCs与卵圆细胞增殖达到顶峰;PH后第12～15天,出现新生小肝细胞结节及小肠样化生,HSCs随卵圆细胞显著减少,位于小肝细胞结节周围,结节内有少量HSCs;PH后第18～21天,HSCs与卵圆细胞进一步减少或消失.直线相关分析表明两者高度相关.结论 HSCs参与了肝卵圆细胞介导的肝再生,可能通过产生多种生长因子以及重塑胞外基质对卵圆细胞的增殖分化具有重要的调控作用.     

大鼠肝卵圆细胞中matrilin-2的表达及其意义

目的探讨大鼠肝脏再生过程中肝卵圆细胞matrilin-2的表达及其意义。方法利用大鼠部分肝切除(PH)或2-乙酰氨基芴灌胃+/部分肝切除(2-AAF/PH)建立大鼠肝脏再生模型,并设正常对照组。应用免疫组织化学和RT-PCR方法研究肝脏组织中matrilin-2表达情况。结果免疫组化发现正常对照组及PH组肝脏组织中只有极少量的matrilin-2表达位于胆管血管周围及肝窦状隙内,而在2-AAF/PH模型中可见matrilin-2表达位于门静脉周围的肝窦状隙内,RT-PCR发现2-AAF/PH组肝卵圆细胞中matrilin-2mRNA高表达,而PH组及正常对照组成熟肝细胞中无matrilin-2mRNA表达。结论matrilin-2是肝卵圆细胞在肝脏再生过程中产生的重要的细胞外基质蛋白,与肝卵圆细胞的增殖分化过程有密切关系。     

Activin A suppressed hepatic oval cell-mediated liver regeneration in vivo

目的 研究Activin A对卵圆细胞介导肝再生的抑制作用及其机制.方法 建立2-乙酰胺基芴/部分肝切除卵圆细胞介导肝再生模型,肝切除后立即经门静脉注射1 μg Activin A(Activin A组),或生理盐水(对照组).肝切除后不同时间点取肝脏标本检测卵圆细胞增殖及肝再生率和磷酸化smad2,p15和p21的表达.结果 Activin A组肝脏中卵圆细胞的增殖及肝再生率均明显低于对照组;Activin A组肝脏中smad2的磷酸化水平及p15,p21的表达水平均高于对照组.结论 Activin A可以通过smad信号通路抑制卵圆细胞介导的肝再生.     

硫氧还蛋白2在2-乙酰氨基芴加肝切除诱导的卵圆细胞中的表达及意义

目的 观察硫氧还蛋白2(Trx2)在2-乙酰氨基芴(2-AAF)加肝切除诱导的卵圆细胞增殖中的表达,并探讨其表达的意义.方法 Balb/c小鼠喂饲2-AAF加2/3肝切除方法诱导肝脏卵圆细胞的增殖.经门静脉灌注消化法和等密度离心法分离卵圆细胞,并在体外进行原代培养.免疫荧光和双标法对培养的细胞进行鉴定.免疫组化法检测卵圆细胞的增殖,免疫荧光法检测Trx2在卵圆细胞和肝实质细胞中的表达,TUNEL法检测卵圆细胞和肝实质细胞的凋亡.结果 喂饲2-AAF后引起肝脏损伤,与肝切除前相比,肝切除后肝脏损伤明显加重(P＜0.01),同时有明显的卵圆细胞增殖.卵圆细胞中Trx2的表达明显高于肝实质细胞,同时其凋亡率明显低于肝实质细胞(P＜0.01).结论 喂饲2-AAF加2/3肝切除可以引起严重的肝损伤,促进卵圆细胞增殖,卵圆细胞高表达Trx2可以抑制自身凋亡和损伤,在肝脏功能的恢复过程中起着非常重要的作用.     

ABCG2/Bcrpl基因在大鼠肝脏卵圆细胞中的表达

目的探讨ABCG2／Bcrp1基因在大鼠肝脏卵圆细胞中的表达及意义。方法建立大鼠2-乙酰氨基芴／三分之二肝切除模型，二步胶原酶灌注结合Percoll密度梯度离心分离大鼠肝脏卵圆细胞，采用荧光定量PCR技术检测ABCG2／Bcrp1基因在大鼠肝脏卵圆细胞和肝细胞中的表达水平，免疫组织化学、免疫荧光双标染色和Westernblot方法检测该转运蛋白的表达。结果大鼠肝卵圆细胞中ABCG2／Bcrp1基因的表达水平是肝细胞的13．8倍，ABCG2／Bcrp1蛋白相对分子质量大小为72000，定位于卵圆细胞膜。其表达位于门脉区周围，并向肝小叶延伸。免疫荧光双标染色显示与OV-6共表达。结论大鼠肝卵圆细胞表达高水平的ABCG2／Bcrp1，后者参与肝干细胞免受外源性化学物质损伤的自我保护机制。     

大鼠2-乙酰胺基芴/部分肝切除模型中卵圆细胞增殖动力学的初步研究

目的 研究大鼠肝脏卵圆细胞增殖模型中卵圆细胞增殖率的变化,进一步了解卵圆细胞生物学特性.方法 采用2-乙酰胺基芴/部分肝切除(2-AAF/PH)的方法建立大鼠肝卵圆细胞增殖模型.免疫荧光双标技术检测肝切除术后不同时间点肝脏石蜡切片中卵圆细胞标志物上皮细胞黏附分子和增殖标志物增殖细胞核抗原的共表达情况,对阳性细胞进行定量计数分析;并采用荧光双标和天狼猩红染色观察此过程中肝星状细胞激活和肝脏胶原沉积的情况.结果 术后第2天门静脉区开始出现少量卵圆细胞,到第9天数量达到高峰,此后数量逐步下降.此过程中卵圆细胞的增殖率逐步下降,从第2天的(91.3±1.6)%下降到第12天的(53.6±4.4)%,差异有统计学意义(P＜0.01).激活的肝星状细胞一直伴随卵圆细胞增殖并向肝实质延伸,分泌的胶原形成细胞外基质包绕小管样结构的卵圆细胞.结论 2-AAF/PH模型中卵圆细胞数量达到高峰前,其增殖率已经开始逐渐下降.肝星状细胞可能通过分泌细胞外基质和多种因子严格调控卵圆细胞的增殖.     

卵圆细胞参与实验性肝癌形成过程的研究

目的探讨卵圆细胞在肝组织内的起源及其与原发性肝细胞肝癌的关系。方法清洁型SD大鼠60只,随机分为正常组(20只)和实验组(40只),各组于开始制造肝癌模型后的不同时段取肝组织标本进行常规病理和C-kit、PCNA免疫组化检测。结果正常组大鼠肝脏表面光滑,组织学形态正常,偶见C-kit和PCNA阳性细胞;实验组于肝脏染毒的第2周,首先于汇管区发现卵圆细胞沿胆管上皮依次排列增生,这些卵圆细胞呈C-kit和PCNA阳性表达。随着染毒加重,卵圆细胞以汇管区为中心向肝小叶穿插生长。肝癌形成时,癌结节内外均见有卵圆细胞聚集,此期c-kit阳性细胞仍以汇管区为主,而PCNA阳性细胞遍布癌结节内外。结论卵圆细胞起源于汇管区的胆管上皮;卵圆细胞与肝癌的发生密切相关。     

肝卵圆细胞在进行性肝损伤过程中分布及迁移的实验研究

目的 探讨卵圆细胞在进行性肝损伤过程中的分布及迁移规律。方法 清洁型SD大鼠60只随机分为对照组(20只)和实验组(40只)，两组均于肝癌造模后的不同时相切取肝组织标本进行形态学观察、常规病理和原癌基因编码蛋白(C-kit)免疫组化检测。结果 对照组大鼠肝脏表面光滑，组织学形态正常，偶见C-kit阳性细胞。实验组于肝癌造模后的第2周，首先于汇管区发现卵圆细胞沿胆管上皮依次排列增生，这些卵圆细胞呈C-kit阳性表达。随着肝损伤进行性加重，卵圆细胞以汇管区为中心向肝小叶穿插、迁移。肝癌形成期，以混合型癌多见，癌结节内外均见有卵圆细胞，此期C-kit阳性细胞仍集中于汇管区。结论 卵圆细胞为肝组织内对损伤反应最敏感的一种细胞；肝卵圆细胞的无序迁移参与假小叶形成；卵圆细胞与肝癌的发生密切相关。     

大鼠肝卵圆细胞的电镜观察及SDF-1/CXCR4轴作用研究

目的 本研究通过应用AMD3100封闭卵圆细胞表面CXCR4受体,从而起到抑制趋化因子SDF-1的生物活性,观察大鼠肝卵圆细胞的生长及SDF-1,CXCR4 mRNA表达情况,探讨SDF-1/CXCR4轴在肝卵圆细胞激活、增殖、分化中所起的作用.方法 建立卵圆细胞增殖模型,分为四组,分别为:2-AAF/PH组,AMD3100/PH组,2-AAF/AMD3100/PH组,PH组,重(150±20)g的Wistar大鼠予2-AAF灌喂,联合2/3肝切除,制作卵圆细胞模型,并通过尾静脉注射AMD3100阻断SDF-1的生物学作用,分别在术后的第3、5、7、10、14、21天6个时间点各处死6只大鼠,取肝脏标本行CXCR4和SDF-1 RT-PCR,检测卵圆细胞CXCR4及SDF-1 mRNA的表达情况,并取第10天肝脏透射电镜检查,观察卵圆细胞的超微结构.结果 给予AMD3100抑制SDF-1作用后,肝脏卵圆细胞数量减少,细胞膜受体CXCR4表达下调,同时SDF-1表达也呈下调趋势.结论 抑制SDF-1活性可以在一定程度上减少卵圆细胞的增殖,SDF-1可以通过自分泌或旁分泌途径激活并促进肝卵圆细胞增殖.     

转化生长因子β1 对大鼠肝卵圆细胞增殖和凋亡的影响

目的 研究转化生长因子-β1(TGF-β1)在肝卵圆细胞增殖过程中发挥的调控作用.方法 60只雄性SD大鼠随机分成实验组和对照组,建立肝卵圆细胞增殖动物模型(2-AAF/PH),采用免疫组织化学、RT-PCR、原位细胞凋亡检测方法,观察上述两组动物模型不同时间点肝脏卵圆细胞增殖情况和TGF-β1 及其受体动态表达变化.结果 实验组在肝切除术后2 d 即出现卵圆细胞,10 d达高峰,16 d 卵圆细胞数目明显减少,肝小叶和肝索结构恢复;TGF-β1 表达在术后6 d开始增多,16 d达高峰,21 d 降至正常水平;TUNEL 染色阳性细胞高峰出现在卵圆细胞的增殖高峰后期,和TGF-β1 表达高峰出现在同一时期.结论 TGF-β1 与卵圆细胞增殖和凋亡密切相关,在肝卵圆细胞增殖过程中起负调控作用.     

Laminin and procollagen-III-peptide as a serum marker for hepatic fibrosis in congenital biliary atresia.

The extracellular matrix (ECM) is a complex of macromolecules that includes collagens, proteoglycans, and complex glycoproteins. In fibrotic liver tissue there is an increase in all of these matrix components, and they increase in serum in the patients with alcoholic hepatitis or liver cirrhosis. These ECM components have been used as a serum marker of hepatic fibrosis. Prolonged obstruction of bile flow results in morphologic and biochemical changes and the development of secondary biliary cirrhosis. In congenital biliary atresia (CBA) there is a close correlation between the degree of the hepatic fibrosis and bile flow after the operation. We estimated that, in CBA, ECM increased in serum, and it would reflect the degree of the hepatic fibrosis. To clarify this we examined the serum procollagen-III-peptide (P-III-P) and laminin in CBA patients. P-III-P was elevated in all preoperative patients but in two of the three postoperative patients whose jaundice disappeared P-III-P was in the normal range. In the all 3 patients whose jaundice continued, P-III-P was in normal range. Serum laminin was elevated in 12 preoperative patients with CBA, but there is no correlation between day of diagnosis and level of laminin. Mean concentration in CBA without jaundice after operation was 3.18 U/mL, 3.226 U/mL in CBA with jaundice and 3.3 U/mL in infantile hepatitis. There were no significant differences among three groups. With the elevation of serum alanine aminotransferase, aspartate aminotransferase, and total bilirubin, serum laminin level was also increased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Extracellular matrix components induce differentiation of the human osteoblastic cell line SV-HFO in a soluble factor-dependent manner

In this study, we examined the effect of extracellular matrix (ECM) components including type I collagen (Col I), type IV collagen (Col IV), laminin, and fibronectin on differentiation of the human osteoblastic cell line SV-HFO when the cells were treated with dexamethasone (Dex), which induces the cells' mineralization. All ECM proteins clearly increased the alkaline phosphatase (ALP) activity of SV-HFO cells in a dose-dependent fashion. Similarly, treatment with 1, 25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) induced the ECM components to enhance the osteocalcin (OC) synthesis of SV-HFO cells. Each ECM component had distinct effects depending on the soluble factor used; with Dex treatment, fibronectin more efficiently increased the ALP activity of Dex-treated SV-HFO cells than Col I, Col IV, or laminin, while with 1,25(OH)₂D₃ treatment, Col IV more efficiently increased on OC synthesis than the other ECMs. We also examined the expression of integrins, an ECM receptor family, using monoclonal antibodies. Flow cytometric analysis demonstrated that SV-HFO cells expressed all very late antigen (VLA) integrins including VLA-1 to VLA-6 as well as _v3 integrin, and that the expression of VLA integrins is regulated by the Dex-induced cell differentiation. These findings suggest that ECM components have soluble factor-dependent stimulatory effects on the regulation of osteoblastic differentiation of SV-HFO cells, possibly through the cell surface ECM receptors in the integrin family.     

Effect of combined antisense oligonucleotides against high-glucose- and diabetes-induced overexpression of extracellular matrix components and increased vascular permeability

The effect of combined antisense oligonucleotides (AS-oligos) against overexpression of extracellular matrix (ECM) components, fibronectin, laminin, and collagen IV and on cell monolayer permeability was examined in rat microvascular endothelial cells (RMECs) grown in high glucose medium and on retinal vascular permeability in diabetic rats. RMECs grown in high glucose for 10 days and transfected with combined AS-oligos showed a significantly reduced fibronectin, laminin, and collagen IV protein level. In parallel studies, high-glucose-induced excess monolayer permeability was also reduced in RMECs transfected with the combined AS-oligos. Similarly, diabetic rats intravitreally injected with the combined AS-oligos and examined after 2 months of diabetes showed significant reduction in retinal fibronectin, laminin, and collagen IV expression. In addition, vascular permeability, as determined from extravasation of fluorescein isothiocyanate-BSA in the surrounding areas of the retinal capillaries, was partially reduced in the combined AS-oligos-treated diabetic retinas. Our results indicate that the combined AS-oligos strategy is effective in simultaneously reducing fibronectin, collagen IV, and laminin overexpression and reducing vascular leakage in the retinal capillaries of diabetic rat retinas. The findings suggest that abnormal synthesis of ECM components may contribute to vascular leakage in the diabetic retina.     

Changes in hepatic venous oxygen saturation related to the extent of regeneration after partial hepatectomy in rats

BACKGROUND: Changes in hepatic oxygen metabolism in relation to the extent of liver regeneration are expected after partial hepatectomy. There are few reports, however, about hepatic oxygen metabolism during liver regeneration. In this study, we evaluated changes in hepatic oxygen metabolism related to the regeneration rate, and the relationship between hepatic venous oxygen saturation (Shvo2) and liver regeneration after partial hepatectomy. METHODS: The work was done using 50% hepatectomized rats with continuous infusion of octreotide for inhibition of liver regeneration or with saline as control. The hepatic hemodynamics, oxygen metabolism, and Shvo2 levels as well as the regenerating liver status were evaluated for 3 days after hepatectomy. RESULTS: Administration of octreotide resulted in a significant reduction of the regenerating liver weight on days 1 and 3 after hepatectomy compared with the control group. Significantly decreased DNA synthesis and proliferating cell nuclear antigen labeling index were also found on day 1. Meanwhile, hepatic oxygen consumption (HVO2) and oxygen extraction ratio were significantly decreased in the octreotide-treated group on day 1. In contrast, the Shvo2 levels in the octreotide-treated group were significantly higher than those in the control group, and were inversely correlated with the HVO2. CONCLUSION: The remnant liver demands an increased amount of oxygen in relation to the extent of regeneration, and changes in the Shvo2 are inversely correlated with the HVo2. Therefore, monitoring the Shvo2 could be useful for estimating liver regeneration after partial hepatectomy.     

c-kit在人肝硬化及肝细胞肝癌组织中的表达及意义

目的探讨肝脏祖细胞标志物c-kit在人肝硬化及肝细胞肝癌（HCC）组织中的表达及其与临床病理特征的关系。方法对30例肝硬化、40例肝细胞肝癌标本及3例正常组织标本进行常规组织学观察以及c-kit、CD45免疫组化染色,对肿瘤细胞的分化程度及肝硬化组织门静脉炎症程度进行分型和评分,分析c-kit表达与肝硬化及肝细胞肝癌的临床病理特征的联系。结果正常肝脏中c-kit染色阴性。20／30例肝硬化中发现c-kit（＋）细胞,位于门脉周围区域和纤维间隔内,个别阳性细胞整合到成熟胆管,肝硬化结节中没有发现c-kit（＋）细胞。19／40例HCC组织中存在c-kit （＋）肿瘤细胞,在肿瘤细胞之间或肿瘤结节周围分散分布。HBsAg及Anti-HBc在c-kit（＋）与c-kit （-）HCC之间表达有显著性差异（χ^2=5．063,P〈0．05;χ^2=6．667,P〈0．05）。c-kit表达与肿瘤的分化程度紧密相关（χ^2=10．384,P〈0．05）,分化程度越低,c-kit表达越高。结论骨髓来源的肝脏祖细胞参与了部分肝硬化病变过程中的肝再生及HCC的形成和发展,c-kit表达情况对于判断HCC预后有一定意义。     

Fibronectin, laminin, and collagen types I, III, IV and V in the healing rat colon anastomosis.

The purpose of this work was to study normal anastomotic healing in the rat colon. The unprepared sigmoid colon was divided and a colo-colostomy performed using a one-layer inverting technique. Frozen sections were taken and studied immunohistologically with specific antibodies to fibronectin, laminin and collagen types I, III, IV and V. From day one onwards a strong fibronectin reaction was observed in the anastomosis, reaching maximum staining intensity on postoperative day five. Type III collagen and pericellular type V collagen were at first detected in the anastomosis on day two. From day three onwards all collagens studied and laminin were present in the repair tissue (laminin and type IV and V collagen in the regenerating capillary walls). Maximum immunofluorescence was observed on day seven and it remained on a high level throughout the study, except for fibronectin, which weakened gradually after the fifth postoperative day. The results indicate that healing of the colon anastomosis occurs by rapid accumulation of connective tissue components between the inverted leaves of the colonic wall, as also new capillaries consisting of the basement membrane components, type IV and V collagen as well as laminin, are formed.     

Mild steatosis impairs functional recovery after liver resection in an experimental model

BACKGROUND: Mild steatosis has been thought not to affect outcome after liver resection. However, recent studies have reported impaired postoperative recovery of patients with mild steatosis. This study evaluated the recovery of hepatic functional reserve during regeneration in a rat model of mild steatosis and liver resection. METHODS: Male Wistar rats had a standard methione- and choline-deficient diet to induce mild steatosis before 70 per cent liver resection. Evaluation of hepatobiliary function was by (99m)Tc-labelled mebrofenin scintigraphy. Mebrofenin uptake rate, the time for maximum uptake (T peak) and the time required for peak activity to decrease by 50 per cent (T(1/2) peak) were assessed 1, 2, 3 and 7 days after liver resection, along with regeneration of the remnant liver, hepatocellular and sinusoidal damage, and hepatic adenosine 5'-triphosphate (ATP) levels. RESULTS: Liver regeneration and proliferative response in mild steatotic rats were no different from those in controls. However, the mebrofenin uptake rate was lower (P < 0.050) and the recovery of hepatic ATP impaired (P < 0.050) in animals with mild steatosis. Hepatocellular damage was increased (P < 0.050) but sinusoidal endothelial cell function was not affected after liver resection in mildly steatotic rats. CONCLUSION: Mild steatosis impaired functional recovery and increased hepatocellular damage after liver resection.