Noninvasive visualization of tumor growth in a human colorectal liver metastases xenograft model using bioluminescence in vivo imaging

Background

Bioluminescence imaging (BLI) is an ideal tool for noninvasive, quantitative monitoring of tumor progression/regression in animal models. The effectiveness of different treatment strategies is displayed by an altered intensity of bioluminescence, demonstrating a change of the tumor burden. The aim of this study was to establish a reliable, reproducible colorectal hepatic metastases cancer animal model.

Methods

Cells of the human colon carcinoma cell line HCT-116 Luc^pos expressing the firefly luciferase enzyme gene were used. HCT-116 Luc^pos cells (2.5 × 10⁶) were injected through the portal vein into the liver of immunoincompetent nude mice. BLI was used to analyze intrahepatic tumor burden and growth kinetic.

Results

HCT-116 Luc^pos cells demonstrated a progressive and reproducible growth in the liver after intraportal injection. Four days after injection, the animals were analyzed for tumor growth by BLI, and mice without or too low bioluminescence signals were excluded (between 10% and 20% animals). HCT-116 Luc^pos intrahepatic tumors responded successfully to different dosages (5 and 10 mg/kg) of 5-fluorouracil.

Conclusions

BLI is an important tool with many potential advantages for investigators. The measurement of intrahepatic tumor growth by imaging luciferase activity noninvasively provides valuable information on tumor burden and effectiveness of therapy. Thus, the presented intrahepatic metastases model based on the growth of HCT-116 Luc^pos cells is suitable for in vivo testing of different cancer therapy strategies.     

Real time shear waves elastography monitoring of thermal ablation: in vivo evaluation in pig livers

Background

Thermal ablation is a widely used minimally invasive treatment modality for different cancers. However, lack of a real-time imaging system for accurate evaluation of the procedure is one of the reasons of local recurrences. Shear waves elastography (SWE) is a new ultrasound (US) imaging modality to quantify tissue stiffness. The aim of the study was to assess the feasibility and accuracy of US elastography for quantitative monitoring of thermal ablation and to determine the elasticity threshold predictive of coagulation necrosis.

Methods

A total of 29 in vivo thermal lesions were performed in pig livers with radiofrequency system. SWE and B-mode images were acquired simultaneously. Liver elasticity was quantified by using SWE data and expressed in kilopascal. After the procedure, pathologic analysis of treated tissues was compared with US images. The sensitivity and positive predictive value of the SWE maps of tissue elasticity were calculated and compared with the boundaries of the pale coagulation necrosis areas found at pathology.

Results

The liver mean elasticity values before and after thermal therapy were 6.4 ± 0.3 and 38.1 ± 2.5 kPa, respectively (P < 0.0001). For a threshold of 20 kPa, sensitivity (i.e., the rate of pixels correctly detected as necrosed tissue) was 0.8, and the positive predictive value (i.e., the rate of pixels in the elastographic map >20 kPa that actually developed coagulation necrosis) was 0.83.

Conclusions

Tissue areas with coagulation necrosis are significantly stiffer than the surrounding tissue. SWE permits the real-time detection of coagulation necrosis produced by radiofrequency and could potentially be used to monitor US-guided thermal ablation.     

Role of liver progenitors in liver regeneration

During massive liver injury and hepatocyte loss, the intrinsic regenerative capacity of the liver by replication of resident hepatocytes is overwhelmed. Treatment of this condition depends on the cause of liver injury, though in many cases liver transplantation (LT) remains the only curative option. LT for end stage chronic and acute liver diseases is hampered by shortage of donor organs and requires immunosuppression. Hepatocyte transplantation is limited by yet unresolved technical difficulties. Since currently no treatment is available to facilitate liver regeneration directly, therapies involving the use of resident liver stem or progenitor cells (LPCs) or non-liver stem cells are coming to fore. LPCs are quiescent in the healthy liver, but may be activated under conditions where the regenerative capacity of mature hepatocytes is severely impaired. Non-liver stem cells include embryonic stem cells (ES cells) and mesenchymal stem cells (MSCs). In the first section, we aim to provide an overview of the role of putative cytokines, growth factors, mitogens and hormones in regulating LPC response and briefly discuss the prognostic value of the LPC response in clinical practice. In the latter section, we will highlight the role of other (non-liver) stem cells in transplantation and discuss advantages and disadvantages of ES cells, induced pluripotent stem cells (iPS), as well as MSCs.     

Effect of Aspergillus fumigatus and Candida albicans on pro-inflammatory response in cystic fibrosis epithelium

Background

The identification of filamentous fungi and/or yeasts in the airway secretions of individuals with cystic fibrosis (CF) is becoming increasingly prevalent; yet the importance of these organisms in relation to underlying inflammation is poorly defined.

Methods

Cystic fibrosis bronchial epithelial cells (CFBE) and human bronchial epithelial cells (HBE) were co-incubated with Candida albicans whole cells or Aspergillus fumigatus conidia for 24 h prior to the measurement of pro-inflammatory cytokines IL-6 and IL-8 by ELISA.

Results

Treatment of HBE or CFBE with C. albicans whole cells did not alter cytokine secretion. However treatment of CFBE with A. fumigatus conidia resulted in a 1.45-fold increase in IL-6 and a 1.65-fold increase in IL-8 secretion in comparison to basal levels; in contrast there was far less secretion from HBE cells.

Conclusion

Our data indicate that A. fumigatus infection modulates a pro-inflammatory response in CF epithelial cells while C. albicans does not.     

Benefit of Kupffer cell modulation with glycine versus Kupffer cell depletion after liver transplantation in the rat: effects on postischemic reperfusion injury, apoptotic cell death graft regeneration and survival.

Inhibition or destruction of Kupffer cells (KC) may protect against ischemia-reperfusion (IR) induced primary graft nonfunction (PNF) in liver transplantation. Besides KC activation, PNF is characterized by microvascular perfusion failure, intrahepatic leukocyte accumulation, cell death and hepatocellular dysfunction. KCs can be inactivated by different agents including gadolinium chloride (GdCl3), methyl palmitate (MP) and glycine. The effects of three KC inactivators on IR-injury after rat liver transplantation were compared in the present study. Lewis liver donors were treated with GdCl3, MP, glycine or saline (control). Liver grafts were transplanted following 24 h storage (UW solution). KC populations and IR damage were assessed by histologic analysis, quantitative real-time polymerase chain reaction (RT-PCR) and intravital microscopy. The number of hepatic ED-1 positive macrophages was diminished after GdCl3 (114.8+/-4.4/mm2 liver tissue) and MP treatment (176.0+/-5.0), versus the glycine (263.9+/-5.5) and control (272.1+/-5.6) groups. All three treatment modalities downregulated phagocytic activity for latex particles, paralleled by reduced microvascular injury (acinar perfusion index, GdCl3: 0.75+/-0.03; MP: 0.83+/-.03; glycine: 0.84+/-0.03; 0.63+/-0.03). Quantitative RT-PCR revealed elevated myeloperoxidase mRNA after glycine versus GdCl3 and MP pretreatment (3.2- and 3.4-fold, P=0.011, respectively), without difference to controls (2.9-fold of glycine). TNFalpha-mRNA was reduced after glycine- (5.2-fold), GdCl3- (19.7-fold), MP-treatment (39.5-fold) compared with controls. However, profound prevention of intrahepatic cell death and liver graft failure was solely achieved with glycine preconditioning. Different than GdCl3 and MP, glycine modulates rather than destroys KCs. Glycine appears to preserve cell viability and to TNFalpha/leukocyte dependent organ regeneration capacity, which is related to increase graft survival following liver transplantation.     

Tyrosine phosphorylation of insulin receptor substrates during ischemia/reperfusion-induced apoptosis in rat liver

Background  Phosphoregulation of signal transduction pathways is a complex series of reactions that may modulate the cellular response to ischemia–reperfusion (I–R). The aim of this study was to evaluate the effect of normothermic liver I/R-induced apoptosis on phosphorylation and activation of signal proteins in tyrosine kinase pathways. Materials and methods  In rats, a segmental normothermic ischemia of the liver was induced for 120 min. Liver apoptosis was determined using terminal deoxynucleotide-transferase-mediated deoxyuridine triphosphate nick end labeling assay, and activity of caspases-3 and -7 was determined by fluorescence. Liver tyrosine phosphorylation of proteins was examined by Western blot analysis. Results  Normothermic I–R resulted in increased in vivo caspases-3 and -7 activity and in liver apoptosis. Shc tyrosine phosphorylation and activation of ERK1/2 were increased after reperfusion, while tyrosine phosphorylation of IRS-1 and activation of PKB/Akt were decreased. Conclusions  Normothermic liver I–R leads to increased apoptosis and to modifications in protein tyrosine phosphorylation pathways. Scientific meetings: Presented to the World Transplant Congress, Boston, USA, July 22–27, 2006, the 7th World Congress of the International Hepato-Pancreato-Biliary Association, Edinburg, UK, September 3–7, 2006, and the 31st Congress of the Società Italiana Trapianti d’Organo, Modena, Italy, November 28–38, 2007. Raffaele Cursio and Claudia Miele have contributed equally to this work     

TAT-血红素氧合酶-1融合蛋白对大鼠供肝冷保存期炎性反应及肝功能的影响

目的 探讨HIV-1反式激活蛋白-血红素氧合酶-1(TAT-HO-1)融合蛋白对大鼠供肝冷保存期炎性反应及肝功能的影响.方法 成年健康雄性SD大鼠48只,体重250～300 g,开腹游离腹主动脉并结扎,于左右髂总动脉分叉处向心端穿刺腹主动脉,切断肝上下腔静脉,随机灌注4℃HTK液(C组,U=24)或4℃含TAT-HO-1融合蛋白50 μg/ml的HTK液(P组,n=24),至流出灌洗液清亮后停止灌注,取肝脏,置于相应保存液中冷保存.分别于冷保存即刻、6、12和18 h时取保存液并切取肝组织.采用全自动生化分析仪测定保存液谷草转氨酶(AST)、谷丙转氨酶(ALT)及乳酸脱氢酶(LDH)活性,免疫组化法检测肿瘤坏死因子α(TNF-α)的表达,光镜下观察肝组织形态学.结果 随冷保存时间延长,两组保存液AST、ALT及LDH活性升高,TNF-α表达上调(P<0.05);与C组比较,冷保存6、12、18 h时P组保存液AST、ALT及LDH活性降低,TNF-α表达下调(P<0.05).结论 TAT-HO-1融合蛋白可抑制大鼠供肝冷保存期的炎性反应,对肝功能具有一定保护作用.     

外源性一氧化碳释放分子2对严重烧伤小鼠肝脏炎性反应的抑制作用

目的 观察外源性一氧化碳释放分子2（CORM-2）对严重烧伤小鼠肝脏炎性反应的抑制作用，并探讨其机制。方法 将C57BL／6小鼠随机分成假伤组（模拟烧伤）、假伤＋CORM-2组、烧伤组、烧伤＋CORM-2组及烧伤＋二甲亚砜（DMSO）组，每组9只。假伤＋CORM-2组除伤后使用CORM-2以外，其他处理同假伤组。烧伤＋CORM-2组及烧伤＋DMSO组除伤后分别使用CORM-2、DMSO外，其余处理同烧伤组。于伤后24h检测小鼠血清丙氨酸转氨酶（ALT）及天冬氨酸转氨酶（AST）的水平，肝组织髓过氧化物酶（MPO）及核因子KB（NF-kB）活性，胞间黏附分子1（ICAM-1）和血管细胞黏附分子1（VCAM-1）蛋白的表达；检测各组小鼠肝窦内皮细胞（HSEC）经各自血清刺激后对中性粒细胞（PMN）的黏附作用。结果 与假伤组比较，烧伤组小鼠血清ALT、AST的水平[（398±34）、（122±22）U／L]及肝组织MPO活性、肝组织ICAM-1和VCAM-1蛋白表达水平均明显升高（P〈0．05或P〈0．01）。与烧伤组比较，烧伤＋CORM-2组上述情况明显改善，且NF-kB活性下降。与假伤组比较，烧伤组小鼠HSEC对PMN的黏附作用增强；烧伤＋CORM-2组该作用明显弱于烧伤组（P〈0．05）。结论 外源性CORM-2能明显抑制肝组织NF-kB活性，减少ICAM-l、VCAM-l蛋白的表达水平，减轻严重烧伤后组织中白细胞滞留，改善肝功能，可有效减轻肝脏炎性反应。     

肝脏缺血再灌注对肝癌肝内转移和生长作用的研究

目的:探讨缺血再灌注时间对肝癌肝内转移生长的作用。方法:建立70%缺血再灌注模型肝癌肝内转移小鼠模型。分为四组:假手术组,缺血15min组,缺血30 min组,缺血45 min组。四组都要在再灌注后注射肿瘤细胞,观察小鼠的生存时间,肿瘤大体观察,肿瘤组织切片HE染色计算肿瘤肝组织被替代区域(HRA)。结果:缺血30 min组和缺血45 min组肿瘤肝脏肝组织被替代区域更大,小鼠生存时间更短。结论:缺血30 min、缺血45 min组肝损伤相对更重,肝内肿瘤转移生长更快。     

重组人促红细胞生成素预先给药对心肌缺血再灌注损伤大鼠心肌炎性反应的影响

目的探讨重组人促红细胞生成素（rhEPO）预先给药对心肌缺血再灌注损伤大鼠心肌炎性反应的影响及其机制。方法健康雄性SD大鼠138只,体重350～450g,随机分为3组：假手术组（Sham组,n=42）、缺血再灌注组（I/R组,n=48）和rhEPO预先给药组（n=48）。缺血前24h,Sham组和I/R组腹腔注射0．9%NaCl溶液4ml/kg,rhEPO预先给药组腹腔注射rhEPO 5 000IU/kg（溶于0．9% NaCl溶液4ml/kg）。采用阻断左前降支冠状动脉30min、再灌注180min制备心肌缺血再灌注损伤模型,分别于结扎冠状动脉前即刻、缺血即刻、再灌注30、60、120、180min 3组各随机处死6只大鼠,取左心室心肌组织,测定肿瘤坏死因子-α（TNF-α）、自细胞介素（IL）-6和IL-10的含量,检测心肌细胞核NF-kB和活化蛋白-1（AP-1）的表达；3组随机另取6只大鼠,再灌注结束时观察心肌中性粒细胞浸润情况。I/R组和rhEPO预先给药组再随机取6只大鼠,再灌注结束时测定心肌梗死面积。结果与Sham组比较,I/R组和rhEPO预先给药组NF-kB、AP-1表达及TNF-α、IL-6、IL-10含量升高（P＜0．01）；与I/R组比较,rhEPO预先给药组NF-kB和AP-1表达及TNF-α、IL-6含量降低,IL-10含量升高（P＜0．05或0．01）；rhEPO预先给药组较I/R组心肌梗死面积减小,中性粒细胞浸润程度减轻。结论预先腹腔注射rhEPO 5 000 IU/kg可减轻大鼠心肌缺血再灌注损伤,其机制与下调NF-kB和AP-1表达,抑制心肌炎性反应有关。     

雷公藤甲素预处理诱导Tregs细胞减轻小鼠肝脏缺血再灌注损伤的实验研究

目的 探讨雷公藤甲素(TPT)预处理减轻小鼠肝脏缺血再灌注损伤的作用及其机制.方法 将C57BL/6小鼠随机分为4组(15只/组):假手术对照组;假手术雷公藤甲素组;实验对照组;雷公藤甲素实验组.两个雷公藤甲素组小鼠术前1周每天给予雷公藤甲素0.1 mg/kg腹腔注射,术前1h加用一次,而两对照组同期仅给予等体积无菌生理盐水腹腔注射.肝脏缺血90 min再灌注24 h后分别采集各组小鼠的血液和肝组织,检测血清丙氨酸转移酶(ALT)、天冬氨酸转移酶(AST)水平.以及肝脏组织丙二醛(MDA)和超氧化物歧化酶(SOD)含量.光镜下观察肝组织的病理学变化.采用流式细胞术检测肝组织中CD4+CD25+Foxp3+T淋巴细胞占CD4+T细胞的百分比,采用实时聚合酶链反应检测肝组织中Foxp3 mRNA的表达.采用酶联免疫吸附试验检测血清中IL-10、IL-6、IL-1β和TNF-α细胞因子含量.结果 雷公藤甲素实验组和实验对照组小鼠血清ALT和AST明显升高,且雷公藤甲素实验组水平低于实验对照组(P＜0.05).假手术雷公藤甲素组和雷公藤甲素实验组与相应假手术和实验对照组相比MDA含量降低,SOD活性升高(P＜0.05).两假手术组肝组织结构正常,实验对照组可见明显的肝组织片状坏死,雷公藤甲素实验组肝小叶结构基本正常.假手术对照组、假手术雷公藤甲素组、实验对照组和雷公藤甲素实验组CD4+CD25+Foxp3+T淋巴细胞占CD4+T细胞的百分比分别为(7.55±1.87)%、(12.59±3.87)%、(7.85±1.07)%和(12.02±3.16)%.假手术雷公藤甲素组和雷公藤甲素实验组Foxp3 mRNA相对表达量高于相应的对照组(P＜0.05).雷公藤甲素实验组较实验对照组相比有升高血清IL-10,降低IL-6、IL-1β和TNF-α细胞因子的含量的作用.结论 雷公藤甲素可减轻小鼠肝脏缺血再灌注损伤,其机制可能与雷公藤甲素诱导上调体内CD4+CD25+Foxp3+调节性T淋巴细胞比例及增加IL-10分泌,抑制IL-6、IL-1p和TNF-α炎症细胞因子有关.

Abstract：

Objective To investigate the effect and related mechanism of triptolide pretreatment to prevent from ischemia/reperfusion (I/R) injury in mice liver. Methods Sixty male C57BL/6 mouse were randomized into four groups (15/group): A:sham group with saline , B: sham group with triptolide, C: saline I/R group, D: triptolide I/R group. The mice were pretreated with either saline or triptolide (0. 1 mg/kg/d) through intraperitoneal (ip) injection for one week. The mouse partial liver model of I/R injury was established, and samples were collected at 24 h after the I/R injury. Results Serum ALT and AST levels were significantly decreased and histological damage was significantly alleviated in the triptolide I/R group as compared with the saline I/R group (P＜0.05), the concentration of MDA in the triptolide groups was significantly decreased, while SOD activity was significantly increased compared with that of the saline I/R group (P＜0.05). The percentages of CD4+ CD25+ regulatory T cells (Tregs) cells among CD4+ T cells in groups A, B, C, and D were(7. 55 ± 1.87)%, (12. 59±3. 87)%,(7. 85±1.07)%, and(12. 02±3. 16)% in liver tissue, respectively. The expression levels of Foxp3 mRNA were significantly higher in the triptolide I/R group than those of saline I/R group (P＜0. 05). ELISA showed that triptolide could significantly inhibit the levels of IL-6, IL-Iβ and TNF-αand promoted the level of IL-10 in the serum (P＜0.05). Conclusion Pretreatment with triptolide could effectively prevent from liver I/R injury, which may be related to the induction of Treg cells by triptolide, the increase in the level of IL-10 in serum, and the inhibition of IL-6, IL-1β and TNF-α production in serum.     

ICAM-1mRNA在大鼠缺血/再灌注肝脏组织中的表达

目的探讨肝脏缺血/再灌注损伤过程中,肝脏组织中ICAM-1mRNA的表达规律及其意义。方法应用RT-PCR技术,观察缺血时间分别为15min、30min及45min的三组大鼠肝脏于再灌注60min时ICAM-1mRNA的表达情况。结果三组肝脏缺血前及缺血末组织内仅有少量ICAM-1mRNA表达于肝细胞,但于再灌注60min时,ICAM-1mRNA表达程度则显著增强,且缺血时间越长的肝脏,其表达强度越高。结论肝脏的缺血能明显诱导再灌注期间肝细胞表达ICAM-1mRNA,增强肝窦内皮细胞的粘附力,进而引发一系列病理生理改变。     

Effect of sex steroids on soleus muscle response in hypocalcemic medium (in vitro)

Purpose

Postoperative hypocalcemia is a frequently encountered complication of thyroid surgery. Since hypocalcemic symptoms are closely associated with sex, the aim of this study is to investigate the effects of sex steroids on muscle tissue under hypocalcemic conditions.

Methods

Six groups consisting of control male (M), control female (F), gonadectomized male (M−), gonadectomized female (F−), estradiol-applied gonadectomized male (MX), and testosterone-applied gonadectomized female (FX) rats were used. Contraction recordings were obtained from soleus muscle flaps. Maximal tension (PT), frequency required for 50% of PT (F50), contraction velocity at F50 (V50), and changes in contraction values (d[PT], d[F50], d[V50]) between normocalcemic and hypocalcemic conditions were calculated.

Results

d[PT], d[F50], and d[V50] were significantly higher in M− and MX groups compared with control M group. Whereas d[PT], d[F50], and d[V50] parameters of the F− group were significantly higher than control F group, d[F50] and d[PT] of the FX group showed no significant change and d[V50] for the FX group was significantly lower. A comparison of control groups showed that d[PT], d[F50], and d[V50] of the F group were significantly higher than those of the M group.

Conclusion

Whereas absence of both testosterone and estradiol caused an increase in hypocalcemia-induced changes in contraction parameters of rat skeletal muscle, presence or application of testosterone clearly stabilized contraction parameters.     

CD4+CD25+调节性T细胞对小鼠肝脏移植自发性免疫耐受的影响

目的 研究CD4+CD25+调节性T细胞在诱导自发性肝脏免疫耐受中的作用.方法 向受体和供体注射抗CD25抗体(PC61)后进行小鼠原位肝脏移植,观测其生存时间.术后20～30 d切取移植肝脏行HE染色,同时观察CD4+CD25+T细胞对CD4+T细胞和CD8+T细胞功能的影响.结果 去除受体而不是供体小鼠的CD4+CD25+T细胞可以导致肝移植排斥反应.而且,去除CD4+CD25+T细胞使移植物的白细胞浸润明显增多,组织损伤加重.同时,去除CD4+CD25+T细胞导致CD4+T细胞的增殖活性和CD8+T细胞的细胞毒活性明显增强.结论 受体来源的CD4+CD25+调节性T细胞在小鼠肝脏移植免疫耐受诱导中起重要作用.

Abstract：

Objective To examine the contribution of CD4+ CD25+ regulatory T cells to liver transplant tolerance. Methods After injection of anti-CD25 monoclonal antibody (mAb, PC61), mouse orthotopic liver transplantation was performed and survivals were determined. The paraffin-embedded sections of hepatic allografts were cut and stained with hematoxylin and eosin (HE). Furthermore, the effect of CD4+ CD25+ regulatory T cells on proliferative response of CD4+ T cells and cytotoxicity of CD8+ T cells was examined by depleting these regulatory T cells. Results Depletion of these cells in the recipients but not in the donors before liver transplantation caused rejection. Histological analyses of hepatic allografts with PC61 treatment showed extensive leukocyte infiltration and tissue destruction, whereas those in the control group showed minimal changes. Moreover, elimination of CD4+CD25+ T cells resulted in the enhancement of both proliferative response of CD4+ T cells and cytotoxicity of CD8+ T cells against donor-type alloantigen. Conclusions These results suggest that CD4+CD25+ regulatory T cells were important for tolerance induction to hepatic allografts.     

Upregulation of let-7a inhibits vascular smooth muscle cell proliferation in vitro and in vein graft intimal hyperplasia in rats

Background

Proliferation of vascular smooth muscle cells (VSMCs) is a crucial event in the pathogenesis of intimal hyperplasia, which is the main cause of restenosis after vascular reconstruction. In this study, we assessed the impact of let-7a microRNA (miRNA) on the proliferation of VSMCs.

Methods

Using miRNA microarrays analysis for miRNA expression in the vein graft model. Lentiviral vector-mediated let-7a was transfected into the vein grafts. In situ hybridization was performed to detect let-7a. Cultured rat VSMCs were transfected with let-7a mimics for different periods of time. Cell proliferation, migration and cell cycle activity were monitored following transfection of the let-7a mimics. Immunohistochemical and Western blotting analysis the expression levels of c-myc and K-ras.

Results

We found that let-7a was the most downregulated miRNA in the vein graft model. In vivo proliferation of VSMCs was assessed in a rat model of venous graft intimal hyperplasia. Let-7a was found to localize mainly to the VSMCs. Let-7a miRNA expression was increased in VSMCs in the neointima of the let-7a treated group. Intimal hyperplasia was suppressed by upregulation of let-7a via lentiviral vector-mediated mimics. In cultured VSMCs, the expression of let-7a increased upon starving, and the upregulation of let-7a miRNA significantly decreased cell proliferation and migration. Immunohistochemical and Western blotting analysis demonstrated that treatment with let-7a mimics resulted in decreased expression levels of c-myc and K-ras.

Conclusions

The results indicate that let-7a miRNA is a novel regulator of VSMC proliferation in intimal hyperplasia. These findings suggest that let-7a miRNA is a promising therapeutic target for the prevention of intimal hyperplasia.     

氯化钆对肝脏缺血再灌注损伤中缺血肝叶Toll样受体2表达的影响

目的观察氯化钆(GdCl_3)对小鼠肝脏部分缺血再灌注损伤模型中缺血肝叶Toll样受体2(TLR2)表达的影响,探讨枯否细胞(KC)参与肝脏缺血再灌注损伤的机制。方法实验小鼠(BALB/C)被分成氯化钆阻断组、非氯化钆阻断组和假手术组等3组。采用免疫组织化学法观察KC和TLR2阳性细胞的分布并分析两者的相关性。实时逆转录-聚合酶链反应(RT-PCR)法定量检测缺血肝叶中TLR2 mRNA的表达。并检测门静脉血浆丙氨酸氨基转移酶(pALT)、肿瘤坏死因子(TNF)-a水平。结果氯化钆阻断组小鼠肝脏KC被抑制,即缺血肝叶CD68染色阳性率下降(32．97±10．55 vs 185．65±21．88,P＜0．01),TLR2阳性细胞明显低于非氯化钆阻断组(75．74±17．44 vs 170．58±25．14,P＜0．01)),且CD68细胞变化与TLR2阳性细胞变化高度相关(r= 0．945,P＜0．01)。氯化钆阻断组小鼠缺血肝叶TLR2 mRNA表达明显低于非氯化钆阻断组(△Ct值：4．02±1．22 vs 1．05±1．02,P＜0．01,△Ct值越大表明基因表达水平越低),但均高于假手术组(act值：1．05±1．02,4．02±1．22．vs 5．08±1．36,P＜0．05)；门静脉血清TNF-a和pALT水平水平较非氯化钆阻断组下降[TNF-a：(84．45±14．73)ng/L vs(112．32±17．56)ng/L,P＜0．05；pALT：(435．89±78．37)U/L vs(890．21±272．91)U/L,P＜0．01],但均高于假手术组(P＜0．01)。结论在肝脏缺血再灌注损伤过程中,氯化钆可能通过抑制小鼠肝脏KC中TLR2的表达,降低KC分泌TNF-a而减轻肝功能损伤。     

Experimental evaluation of the effects of the intraportal administration of cyclic guanosine monophosphate on ischemia/reperfusion in the porcine liver

This study was done to examine the protective effects of cyclic guanosine monophosphate (cGMP), a second messenger of nitric oxide, for ischemia/reperfusion injury of the liver, since it is known to induce vasodilatation and to inhibit platelet aggregation. Using an experimental model of porcine liver ischemia, 8-bromoguanosine 3′,5′ monophosphate, a cGMP analog, was continuously administered into the portal vein before ischemia and after reperfusion 30 min for each in the cGMP group (n=6). Saline water was administered in the same way in the control group (n=6). The cardiac output (CO), mean arterial blood pressure (MAP), portal venous flow (PVF), hepatic arterial flow (HAF), hepatic tissue blood flow (HTBF), and hepatic tissue cGMP level were determined. Hepatic enzymes and the bile discharge were also assessed as indicators of hepatic function. The hepatic tissue cGMP level was significantly higher, and PVF, HTBF, and the bile discharge were significantly greater in the cGMP group, while there were no remarkable differences between the groups with CO, MAP, HAF, and hepatic enzymes. In conclusion, the continuous supplementation of cGMP into the portal vein was found to be beneficial for preserving both the hepatic circulation and, consequently, the hepatic function of after warm ischemia of porcine liver.