结肠癌细胞获得性5氟尿嘧啶耐药的机制研究

目的： 探讨结肠癌细胞获得性5氟尿嘧啶耐药的机制。 方法： 建立5-FU耐药的结肠癌细胞，通过免疫印迹法检测多种耐药相关蛋白的表达，分析耐药的可能机制。 结果： 反复用5-FU处理结肠癌DLD1和DLD1-TRAIL/R细胞，得到5-FU耐药的DLD1-5-FU/R和DLD1-TF/R细胞，进一步研究发现,5-FU不能诱导耐药细胞发生S期停滞和DNA损伤。接着发现耐药细胞中有过表达的Bik、Bcl-Xs和Bcl-XL蛋白，而DLD1亲代细胞过表达Bcl-XL后，能够部分抵抗5-FU诱导的凋亡，但仍不能耐受5-FU诱导的S期停滞和DNA损伤。结论： 过表达的Bcl-XL蛋白对结肠癌细胞获得性5-FU耐药具有一定作用，但过表达Bcl-XL不影响5-FU诱导的DNA损伤和细胞周期的改变，这提示结肠癌获得性5-FU耐药还存在着Bcl-XL之外的其它机制。     

Prevention of oral mucositis due to 5-fluorouracil treatment with oral cryotherapy

INTRODUCTION: One of the most common and important side effects of 5-fluorouracil (5-FU) is mucositis with ulcerations in the oral cavity. We investigated the effects of local cryotherapy on mucositis incidence administrated durng 5-FU treatment. METHODS: In a total of 99 courses, 5-FU and folinic acid combination chemotherapy was given to 40 patients. In our study, we considered every course as a single case, and cryotherapy was given to the same patient in one course but not given in the next. RESULTS: While mucositis developed in 6.7% of the courses given with cryotherapy, this ratio was 38.9% in courses given without cryotherapy. In the logistic regression analysis, development of mucositis had been found to correlate only with cryotherapy. Odds ratio (OR) = 11.5; in the 95% confidence interval (CI) = 3.2 - 41.9; (p = 0.001). DISCUSSION: Results of initial studies evaluating the effects of cryotherapy in preventing mucositis due to 5-FU based chemotherapy regimens were promising. We concluded that oral cooling prevents 5-FU induced mucositis. This effective prophylactic treatment should be used in patients who are at increased risk for developing 5-FU induced mucositis.     

Periodontitis destructions are restored by synthetic glycosaminoglycan mimetic

Periodontitis are bacterium-driven inflammatory diseases that destroy tooth-supporting tissues whose complete restoration is not currently possible. RGTA, a new class of agents, have this capacity in an animal model. Periodontitis was induced in hamsters and, starting 8 weeks later, injected RG1503, a glycosaminoglycan synthesized from a 40 kDa dextran behaving like a heparan sulfate mimetic (1.5 mg kg(-1) w(-1)) or saline for 8 weeks. The three periodontium compartments were evaluated by immunohistochemistry and morphometry. The gingival extracellular matrix disorganized by inflammation was restoring under treatment. The collagen network was repaired and resumed its previous organization. Fibrillin-1 expression was restored so that the elastic network rebuilt at a distance from the pocket and began to reconstruct near the pocket. Apoptotic cell numbers were decreased in the pocket epithelium, and more so in the infiltrated connective tissue. The continuity and the thickness of the basement membrane were restored and testified normalization of epithelium connective tissue interaction. The amount of alveolar bone increased around the first molar, and the interradicular bone was rebuilt. The root cementum was thickened and the number of proliferating cells in the periodontal ligament was increased close to the cementum. RG1503 treatment induces potent anabolic reactions in the extracellular matrices of the different tissues of the periodontium and recruitment of progenitors. In particular, the cell proliferation close to the root surface suggests the reformation of a functional attachment apparatus. These results demonstrate that RG1503 reverses the degenerative changes induced by inflammation and favors the conditions of a regenerative process. Thus, RGTA, a known matrix component mimetic and protector, may be considered as a new therapeutic tool to regenerate the tissues destroyed by periodontitis.     

Protective effect of Curcumin on chemotherapy-induced intestinal dysfunction

Objective: Chemotherapy is one of most important treatments for human cancers. However, side effects such as intestine dysfunction significantly impaired its clinical efficacy. This study aimed to investigate the protective effect of Curcumin on chemotherapy-induced intestinal dysfunction in rats. Methods: Sixty healthy Wistar rats were randomly divided into control group (normal saline), 5-FU group and 5-FU+Curcumin group. The weight, serum level of endotoxin, DAO and D-lactate were determined. The pathological change of intestinal mucosa structure was studied under light microscopy and electron microscopy. The expression of Bax, Bcl-2 and Caspase-3 were assessed by immunohistochemical staining. Results: The Curcumin intragastrically administrated obviously reduced 5-FU-induced weight-loss. 5-FU induced dramatic increase of serum endotoxin, D-lactate and D-Amino-Acid Oxidase (DAO) that were significantly reversed by Curcumin treatment. Meanwhile, 5-FU-induced-damage to intestinal mucosa structure was markedly recovered by Curcumin. The expression of Bax and Caspase-3 were dramatically increased after 5-FU treatment (p<0.01) and Curcumin treatment significantly reduced Bax expression (p<0.05) but had only a moderate effect on reducing caspase-3 expression (p>0.05). Interestingly, Bcl-2 expression was low in control group but increased after 5-FU treatment (p>0.05) and Curcumin treatment further stimulated Bcl-2 expression (p<0.05). Conclusions: Curcumin can significantly reverse chemotherapy-induced weight-loss, increase of serum endotoxin, D-lactate and DAO and damage to intestinal mucosa structure. Curcumin also reduced the expression of pro-apoptotic Bax but stimulated anti-apoptotic Bcl-2 to attenuate 5-FU-induced apoptosis of intestinal epithelial cells. The clinical administration of Curcumin may improve chemotherapy-induced intestinal dysfunction, thus increasing the clinical efficacy of chemotherapy.     

芸香苷逆转人大肠癌LoVo/5-氟尿嘧啶细胞耐药性及其机制

目的 探讨芸香苷（RT）对大肠癌耐药株LoVo/5-氟尿嘧啶（5-FU）细胞耐药性的影响及其机制。方法 采用浓度梯度递增法建立耐药株LoVo/5-FU细胞;用不同剂量的RT和（或）5-FU处理48 h后,采用细胞计数试剂盒8（CCK-8）法检测细胞活力,流式细胞术检测细胞凋亡和细胞周期,RT-PCR法检测P-糖蛋白（P-gp）和多药耐药相关蛋白1（MRP1）的mRNA表达水平,Western blotting法检测P-gp、MRP1、磷酸化蛋白激酶B（p-Akt）、Akt、Survivin、细胞周期蛋白A（cyclin A）和细胞周期素依赖性蛋白激酶2（CDK2）的蛋白表达水平。结果 LoVo/5-FU细胞中P-gp、MRP1和Survivin蛋白表达水平均显著高于LoVo细胞;5-FU和RT对LoVo/-FU细胞的半数抑制浓度（IC₅₀）分别为21.77 mg/L和98.43 mg/L;在10 mg/L RT作用下,5-FU对LoVo/5-FU细胞的IC₅₀ 降至10.64 mg/L,逆转倍数为2.05;RT可协同增强5-FU引起的LoVo/5-FU细胞凋亡和S期阻滞,抑制P-gp和MRP1基因表达以及Akt磷酸化,下调Survivin、cyclin A和CDK2蛋白水平。结论 RT可通过抑制Akt信号通路以及耐药相关蛋白的表达反转LoVo/5-FU细胞对5-FU的耐药性。     

脂质体介导Clusterin反义寡核苷酸抑制胰腺癌细胞侵袭力及增强5—FU化疗敏感性的实验研究

目的 研究Clusterin反义寡聚脱氧核苷酸(Clusterin ASO)对胰腺癌细胞侵袭力及5-FU化疗敏感性的影响.方法 采用脂质体法将Clusterin ASO转染PANC-1细胞24 h,然后将该细胞暴露于不同浓度的5-FU中,TUNEL法检测72 h后的细胞凋亡指数,MTT检测细胞增殖并计算IC50.观察Clusterin ASO转染对PANC-1细胞体外侵袭力的抑制作用.采用免疫组化,Western blot和RT-PCR技术检测不同处理组细胞中Clusterin和其mRNA和蛋白表达.结果 Clusterin ASO转染可有效沉默PANC-1细胞内Clusterin mRNA及蛋白表达;PANC-1细胞的5-FU IC50为9±0.7,PANC-1/Clusterin ASO的5-FU IC50为1.06±0.3,敏感性增加了9倍.5-FU以剂量依赖方式诱导PANC-1细胞凋亡,但对PANC-1/Clusterin ASO细胞所诱导的凋亡比PANC-1细胞更明显.重组细胞基膜侵袭实验显示,PANC-1细胞与PANC-1/Clusterin ASO细胞的穿透基膜细胞数分别为213±18个和43±8个/高倍镜(×200),差异有统计学意义(P<0.05).结论 靶向Clusterin抑制胰腺癌细胞侵袭力和增殖,并增强胰腺癌细胞对5-FU的化疗敏感性.     

A prostaglandin E1 analog, OP-1206, alleviates 5-fluorouracil-induced injury of rat small intestine

5-Fluorouracil (5-FU) often causes the gastrointestinal toxicity, including enterocolitis. We investigated effects of OP-1206 (17S, 20-dimethyl-trans-delta2-prostaglandin E1) on 5-FU-induced leukocyte infiltration and epithelial barrier dysfunction of rat small intestine. Myeloperoxidase (MPO) activity of the small intestine was assayed as an index of leukocyte infiltration. Intestinal epithelial permeability was determined by the small intestinal absorption of a paracellular permeation marker, fluorescein isothiocyanate-labeled dextran (molecular weight; 4,400) (FD-4) using the in situ closed intestinal loop technique. The MPO activity and FD-4 permeation were significantly increased by the administration of 5-FU to rats for 4 days, while on the coadministration of 5-FU and OP-1206, they were similar to those of control rats treated with saline solution alone, respectively. These observations indicate that OP-1206 reduced the leukocyte infiltration and the change in epithelial permeability of rat small intestine induced by 5-FU.     

Effect of antitumor polysaccharide SPR-901 on antitumor activity in combination with 5-FU

We have examined the effects of the antitumor polysaccharide SPR-901 in combination with 5-fluorouracil (5-FU) on the antitumor activities agains mouse syngeneic tumors. SPR-901 was administered p.o. from day 1 to day 10 at the dose rate of 30 mg/kg, and 5-FU was injected i.p. from day 1 to day 5 at the dose rate of 20 mg/kg after BALB/c mice were injected s.c. with 6 × 10⁴ cells/mouse of Meth A on day 0. Tumor sizes of mice treated with both SPR-901 and 5-FU were significantly smaller than those from the untreated control group on days 10, 15 and 20. LAK activity of spleen cells from mice treated with both SPR-901 and 5-FU was higher than that from the untreated control group and either the SPR-901 or 5-FU treated group. Flow cytometrical analysis revealed that spleen cells from mice treated with both SPR-901 and 5-FU were much more abundant in both T-cell receptor α/β⁺ and IL-2 receptor α⁺ T-cells. Furthermore, spleen cells from both the SPR-901- and 5-FU-treated groups.exhibited higher growth responses to IL-2 than that from the untreated control group either of the SPR-901- or 5-FU-treated groups.Therefore, the effects of the antitumor polysaccharide SPR-901 used in combination with 5-FU were augmented as compared with single drug use.     

Effect of granulocyte macrophage-colony stimulating factor (GM-CSF) on 5-FU-induced ulcerative mucositis in hamster buccal pouches.

The present study was performed to investigate the protective effects of granulocyte macrophage-colony stimulating factor (GM-CSF) against ulcerative mucositis in hamster buccal pouch. GM-CSF was topically administered to the buccal pouches of hamsters with two different doses of 5 and 20 microg/ml. The treatment of GM-CSF led to rapid healing effects in gross and histopathological findings. It decreased expression of pro-inflammatory cytokine mRNA levels in the mucosal tissue of buccal pouches. Also GM-CSF-treated animals showed high numbers of Ki-67 positive cells in basal cell layer. These results suggest that GM-CSF provided excellent healing effects to ulcerative mucositis in the buccal pouch of hamster.     

Thymosin alpha 1 exerts protective effect against the 5-FU induced bone marrow toxicity

Thymosin alpha 1 was shown to prevent the 5-fluorouracil(5-FU)-induced bone marrow toxicity in BDF1 mice, as determined by the cellularity, haemopoietic stem cells (CFU-s) and granulocyte-macrophage colony forming unit (GM-CFU). Furthermore, thymosin alpha 1 increased the levels of colony stimulating factor (CSF) in sera or in culture media of spleen cells derived from 5-FU-treated mice. The treatment of spleen cells with anti-Thy 1,2 antibody plus complement abolished completely the CSF production. The in vivo treatment of donor mice with anti-Thy 1,2 antibody following 5-FU abolished completely the capability of their bone marrow cells to save lethally irradiated recipients. Thymosin alpha 1 treatment prevented the damage by such combined treatment. The present study indicates that thymosin alpha 1 exerts its protective effect against the 5-FU-induced bone marrow toxicity, at least partially, through its effect on the maturation of immature T cells to functional T cells which produce various kinds of lymphokines including CSF.     

人支气管上皮损伤修复过程中Rhodamine 123 染色的动态观察

目的探讨离体人支气管上皮经5-氟尿嘧啶（5-FU）损伤前后及修复过程中支气管上皮细胞Rhodamine 123的染色情况。方法分别取5-FU作用前后及修复3、6、24h的人支气管上皮,蛋白酶消化法获取细胞悬液,进行流式细胞仪分析：1．应用PI染色,确定细胞周期中各期细胞所占百分数;2．Rhodamine 123染色,计算Rhodamine 123阴性细胞占活细胞的比例。结果1．5-Fu处理后支气管上皮细胞中凋亡细胞增多,增殖期（S＋G2/M期）细胞明显减少,剩余细胞绝大部分处于细胞周期的静止（G0/G1）期;随支气管上皮的恢复,S＋G2/M期细胞增多;2．5-FU作用后支气管上皮中Rhodamine 123阴性细胞占活细胞的比例较正常组增多;随着损伤的修复,Rhodamine 123阴性活细胞所占比例逐渐降至接近正常。结论5-Fu的作用使增殖期细胞凋亡、脱落,残留静止期细胞,其中包含具有Rhodamine 123排出能力的干细胞,由它们完成损伤的修复。应用Rhodamine 123染色,经流式细胞仪分选5-Fu作用后残留的细胞,可用于富集纯化支气管干细胞。     

二氢青蒿素通过抑制SIRT1的表达而增强5-氟尿嘧啶对胃癌的抗肿瘤活性

目的:探讨二氢青蒿素对5-氟尿嘧啶治疗胃癌的辅助作用并研究其机制。方法:实验分为对照组、二氢青蒿素组、5-氟尿嘧啶组、5-氟尿嘧啶联合二氢青蒿素组和5-氟尿嘧啶+二氢青蒿素+SIRT1质粒组。MTT法检测胃癌细胞系BGC-823在5-氟尿嘧啶联合二氢青蒿素处理下的细胞活力。Western blot实验检测5-氟尿嘧啶联合二氢青蒿素对BGC-823细胞SIRT1和NADPH氧化酶表达水平,caspase-9和caspase-3活化水平及凋亡信号调节激酶1(ASK1)和c-Jun氨基末端激酶(JNK)蛋白磷酸化水平的影响。流式细胞术检测BGC-823细胞在5-氟尿嘧啶和二氢青蒿素联合处理下的活性氧簇(ROS)生成水平和细胞凋亡率。结果:二氢青蒿素处理能显著抑制BGC-823细胞SIRT1的表达并增加NADPH氧化酶的蛋白水平,明显提高BGC-823细胞对5-氟尿嘧啶的敏感性,降低5-氟尿嘧啶的半数抑制浓度;转染SIRT1表达质粒后,二氢青蒿素联合5-氟尿嘧啶对BGC-823细胞的杀伤活性受到显著抑制(P0.05)。二氢青蒿素能明显促进5-氟尿嘧啶对BGC-823细胞生成ROS的诱导效应和ASK1及JNK的磷酸化(P0.05)。用ROS清除剂N-乙酰半胱氨酸(NAC)或JNK特异性抑制剂SP600125处理后,二氢青蒿素联合5-氟尿嘧啶对BGC-823细胞的杀伤活性和caspase-9及caspase-3的活化均受到明显抑制(P0.05)。另外,NAC能显著抑制二氢青蒿素联合5-氟尿嘧啶对JNK磷酸化的促进作用,而SP600125却不能影响BGC-823细胞ROS的产生,表明JNK是ROS的下游分子。结论:二氢青蒿素联合5-氟尿嘧啶通过SIRT1/NADPH氧化酶/ROS/JNK通路诱导胃癌细胞发生caspase依赖的凋亡。     

PPZ与5-FU对胃癌细胞生长、自我更新能力的影响及相互作用

目的 探讨泮托拉唑（PPZ）、5-氟尿嘧啶（5-FU）在调控胃癌细胞及胃癌干细胞生长、自我更新能力中的影响及其相互作用。方法 将SGC-7901和HGC-27细胞分为3组实验:5-Fu处理组、PPZ处理组和5-Fu+PPZ组。通过细胞成球实验检测PPZ加药前后胃癌细胞系（SGC7901、HGC-27）中胃癌细胞及胃癌干细胞自我更新能力的变化,观察PPZ对胃癌细胞系成球能力干扰情况;MTT法检测PPZ、5-FU对胃癌细胞及胃癌干细胞增殖能力的影响,观察PPZ对5-FU药物敏感性的调节作用。结果 PPZ加入后胃癌细胞系（SGC7901、HGC-27）和胃癌干细胞系（SGC7901-SP、 HGC-27-SP）自我更新率比PPZ加入前的自我更新率下降（P＜0.01）;PPZ、5-FU对胃癌细胞（SGC7901、HGC-27）增殖均有抑制作用,而5-Fu+PPZ联合组抑制最为明显,抑制增殖的作用在24 h开始出现,96 h最低,均低于0 h。PPZ对胃癌干细胞（SGC7901-SP、HGC-27-SP）增殖均有抑制作用,在48 h逐渐明显;加入PPZ后,胃癌干细胞（SGC7901-SP、HGC-27-SP）两个细胞系酶标仪检测到的吸光值在48 h、72 h、96 h时均下降。72 h和96 h时,加与不加PPZ的吸光值比较,统计学意义显著（P＜0.01）。不同浓度（0~50 μg/ml）5-FU对胃癌干细胞（SGC7901-SP、HGC-27-SP）增殖抑制的差异不显著;而加入PPZ 100 μg/ml后,随着5-FU浓度的增加增殖抑制作用逐渐增强,在40~50 μg/ml浓度的5-FU对胃癌干细胞（SGC7901-SP、HGC-27-SP）增殖抑制更加明显;加入PPZ 后,40 μg/ml及50 μg/ml浓度的5-FU作用下胃癌干细胞（SGC7901-SP、HGC-27-SP）酶标仪检测到的吸光值均降低。结论 PPZ能有效抑制胃癌细胞及胃癌干细胞的自我更新能力,抑制其增殖,并可提高其对5-FU的化疗敏感性。PPZ有望成为逆转胃癌耐药的一类联合治疗药物应用于临床。     

The potential protective role of taurine against 5-fluorouracil-induced nephrotoxicity in adult male rats

Nephrotoxicity is common with the use of the chemotherapeutic agent 5-Fluorouracil (5-FU). The current study aimed to investigate the probable protective effect of taurine (TAU) against 5-FU-induced nephrotoxicity in rats using biochemical, histological and ultrastructural approaches. Twenty-four rats were equally divided into control, TAU, 5-FU and 5-FU + TAU groups.5-FU significantly elevated levels of blood urea nitrogen (BUN), creatinine, and uric acid; while it reduced activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Also, 5-FU induced significant elevation in malondialdehyde (MDA) levels accompanied with marked decline in γ-glutamyltranspeptidase (GGT) and alkaline phosphatase (AP) levels in kidney tissues. These biochemical alterations were accompanied by histopathological changes marked by destruction of the normal renal structure, in addition to ultrastructural alterations represented by thickened and irregular glomerular basement membranes, congested glomerular capillaries, damaged lining fenestrated endothelium, mesangial cells hyperplasia with expanded mesangial matrix, and distorted podocyte’s processes. Also, the proximal (PCT) and distal (DCT) convoluted tubules showed thickened basement membranes, destructed apical microvilli and loss of basal infoldings of their epithelial cells.Administration of TAU to 5-FU-treated rats reversed most of the biochemical, histological, and ultrastructural alterations. These results indicate that TAU has a protective effect against 5-FU-induced nephrotoxicity.     

凋亡抑制蛋白XIAP和促凋亡因子Smac在胰腺癌化疗抵抗中的作用

目的探讨x-相关凋亡抑制蛋白（XIAP）和促凋亡因子Smac在胰腺癌细胞化疗抵抗中的作用，以及转染胞浆表达型Smac基因靶向下凋XIAP对化疗药物诱导的胰腺癌细胞凋亡的影响。方法应用流式细胞术检测顺铂、5-FU介导的Panc-1、BXPC-3的凋亡率及胞浆染色分析细胞XIAP表达变化，Western blot分析XIAP、Smac、Caspase-3表达水平；构建pEGFP-NI／Smac真核表达载体并转染胰腺癌Panc-1细胞，流式细胞术检测转染Smac基因前后Panc-1细胞的凋亡敏感性。结果与BXPC-3细胞相比，Panc-1对顺铂或5-FU介导的凋亡具有较强抵抗性，Western blot分析显示Panc-1细胞高表达XIAP，在化疗药物作用下化疗敏感细胞BXPC-3胞浆内XIAP水平下降明显多于Panc-1细胞，而且凋亡的BXPC-3细胞释放入胞浆内的成熟Smac蛋白水平明显高于Panc-1细胞。转染胞浆表达型Smac基因至化疗抵抗Panc-1细胞，可明显下调其XIAP表达水平，促进效应Caspase-3分子活化，显著提高顺铂、5-FU诱导的细胞凋亡率。结论胰腺癌细胞XIAP的表达水平下调与其化疗敏感性有关，XIAP是克服化疗抵抗的重要靶分子，而上调Smac活性蛋白的胞浆表达作为一种有效调节信号，通过拮抗XIAP的凋亡抑制作用协同化疗药物促进胰腺癌细胞凋亡。     

17-二甲基胺乙基-17-去甲氧基格尔德霉素对人胃癌裸鼠移植瘤血管内皮生长因子表达的抑制作用

目的:观察热休克蛋白90(HSP90)抑制剂17-二甲基胺乙基-17-去甲氧基格尔德霉素(17-DMAG)对人胃癌裸鼠移植瘤生长的影响,探讨17-DMAG对胃癌生长和血管生成的抑制作用。方法:用人胃癌细胞HGC-27接种于裸鼠皮下,建立裸鼠胃癌移植瘤模型;将荷瘤裸鼠随机分为3组,每组8只:17-DMAG组(腹腔注射17-DMAG 25 mg/kg)、5-氟尿嘧啶(5-FU)组(腹腔注射5-FU20 mg/kg)及对照组(腹腔注射生理盐水10mL/kg),4周后测量裸鼠移植瘤的体积及重量,HE染色观察形态学变化,同时采用免疫组化方法检测肿瘤组织中CD31(以阳性细胞数计算肿瘤微血管密度)及血管内皮生长因子(VEGF)的表达,采用Western blotting法检测VEGF的表达。结果:17-DMAG组移植瘤体积为(288.10±23.32)mm3,5-FU组移植瘤体积为(366.37±26.42)mm3,对照组移植瘤体积为(957.66±117.51)mm3,前二者与对照组比较,均差异显著(P0.05)。移植瘤重量与对照组比较,17-DMAG组(0.41±0.02)g明显低于对照组(1.12±0.08)g,P0.05;5-FU组(0.48±0.05)g也明显低于对照组(1.12±0.08)g,P0.05;17-DMAG组和5-FU组抑瘤率分别63%和57%,2组抑瘤率无明显差异。17-DMAG组微血管密度(21.72±1.24)比对照组(37.78±1.68)明显减少,P0.05;5-FU组(36.70±1.51)和对照组(37.78±1.68)之间没有显著差异;17-DMAG组肿瘤组织中VEGF的表达(15.39±4.37)明显低于对照组(36.45±7.45)和5-FU组(26.11±6.26)。结论:热休克蛋白90抑制剂17-DMAG可通过降低胃癌组织中血管内皮细胞生长因子的表达抑制肿瘤新生血管的生成,进而抑制裸鼠移植瘤的生长。     

大鼠气管损伤修复过程中ABCG2转运蛋白的表达

目的观察离体大鼠气管上皮损伤修复过程中气管干细胞的动态变化.方法用氟脲嘧啶（5-FU）造成离体大鼠气管上皮损伤,应用间接免疫荧光法和Western blotting动态观测了修复过程中各时间点气管上皮ABCG2的表达.结果 1.5-FU作用12 h后大部分气管上皮脱落,残留的G0期细胞中部分可见ABCG2表达阳性.去除5-FU后3 h细胞数目增多,为扁平状,ABCG2阳性细胞数也随之增多;6～9 h上皮细胞由扁平变为立方,ABCG2阳性细胞数继续增多;24 h上皮细胞呈立方状,并连接成片,ABCG2阳性细胞较前明显减少;48 h气管上皮接近恢复假复层结构,此时仅见极少量ABCG2阳性细胞.正常气管上皮未检测到ABCG2表达.2.Western blotting分析表明,ABCG2表达量的变化趋势与免疫荧光结果一致.结论 ABCG2的表达与干细胞的数量呈正相关,可作为气管干细胞的标志物.     

CD8 alpha-deficient mice are highly susceptible to 5-fluorouracil-induced lethality

Intestinal intraepithelial lymphocytes (i-IEL) expressing CD8 alpha are located in the intestine and may confer protection against invasion of intestinal microflora. We found that mice rendered deficient in CD8 alpha molecules by homologous recombination were susceptible to 5-fluorouracil (5-FU)-induced lethality accompanied by translocation of members of the enterobacteria. The number of i-IEL was greatly reduced on day 6 after 5-FU administration in both CD8 alpha(+/-) mice and CD8 alpha(-/-) mice, whereas the recovery of the level of i-IEL thereafter was significantly impaired in CD8 alpha(-/-) mice compared with that in CD8 alpha(+/-) mice. The ability of i-IEL to produce gamma interferon in response to immobilized T-cell receptor (TCR) alpha beta or TCR gamma delta monoclonal antibodies was significantly lower in CD8 alpha(-/-) mice than in CD8 alpha(+/-) mice. Transfer of CD8(+) i-IEL conferred significant protection against 5-FU-induced lethality in CD8 alpha(-/-) mice. The results suggest that CD8(+) i-IEL play an important role in protection against 5-FU-induced lethality with translocation of Enterobacteriaceae.     

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目的:氧化苦参碱联合5-FU 对人胃癌SGC-7901 细胞生长的协同抑制作用及相关机制研究。方法:通过不同浓度的氧化苦参碱单独及联合应用5-FU 作用于SGC-7901 细胞24、48、72 h,采用MTT 法检测细胞活力,HOECHST 染色法检测细胞凋亡,免疫细胞法检测胃癌SGC-7901 细胞内血管内皮生长因子(VEGF)蛋白的表达,以逆转录聚合酶链式反应RT-PCR 法观察SGC-7901 细胞VEGF mRNA 的转录情况。结果:与空白组比,氧化苦参碱中剂量、高剂量组及其联合5-FU 组均能显著抑制人胃癌SGC-7901 细胞生长,并诱导其凋亡(P<0.01);与单独使用5-FU 组相比,联合用药组细胞增殖抑制率和凋亡率均显著增高(P<0.05);氧化苦参碱及联合5-FU 组中人胃癌SGC-7901 细胞的VEGF mRNA 转录及其蛋白表达显著降低(P<0.01)。结论:氧化苦参碱对5-FU 的胃癌SGC-7901 细胞的增殖抑制和诱导凋亡具有协同作用;促进氧化苦参碱对VEGF 的基因和蛋白表达抑制作用可能是其机制之一。