双氢青蒿素对白血病多药耐药K562/ADM细胞的逆转作用

目的:探讨双氢青蒿素(Dihydroartemisinin,DHA)在白血病多药耐药中的应用。方法:采用MTT检测DHA联合阿霉素(adriamycin,ADM)对白血病多药耐药细胞(K562/ADM)生长增殖的影响;应用流式细胞技术分析细胞内罗丹明123(Rhodamine 123)浓度,以检测DHA对白血病细胞膜P糖蛋白(P-glycoprotein,P-gp)泵功能的影响;免疫组化方法检测DHA对白血病细胞P-gp表达水平的影响。结果:10、20、40μmol/L DHA实验组的细胞耐药逆转倍数分别为1.46、2.16和3.52倍。DHA使用前、后K562/ADM细胞膜P-gp表达水平无明显差异;Rh123蓄积试验中DHA应用后使K562/ADM细胞内Rh123浓度由用前的22.16%升至89.18%,Rh123外排试验中DHA应用后使K562/ADM细胞内Rh123浓度由用前的27.15%升至60.51%。结论:DHA:能有效逆转白血病细胞的MDR机制为通过抑制肿瘤细胞膜上P-gp的药泵功能,增加耐药细胞内化疗药物浓度逆转耐药性,而不是抑制和P-gp表达。     

中药功劳木提取物对肿瘤MDR的逆转作用

目的:研究中药功劳木的4种不同工艺提取物逆转肿瘤多药耐药性(multidrug resistance,MDR)的作用,以开发新型的肿瘤MDR逆转剂。方法:采用MTT法检测4种提取物的细胞毒性及其对阿霉素(adriamycin,ADM)的增敏效果;罗丹明123(Rhodamine123,Rh123)蓄积实验检测4种提取物对细胞内药物浓度及P-糖蛋白(P-glycoprotein,P-gp)功能的影响;流式细胞仪检测4种提取物对耐药肿瘤细胞凋亡的影响。结果:10 mg/L为4种提取物的无毒剂量;在此剂量下,4种提取物对K562/ADM细胞逆转倍数分别为Ⅰ-4.81倍,Ⅱ-2.31倍,Ⅲ-4.17倍,Ⅳ-2.39倍,对MCF-7/ADM细胞的逆转倍数分别为Ⅰ-1.82倍,Ⅱ-1.40倍,Ⅲ-2.54倍,Ⅳ-1.51倍;此剂量的4种提取物应用后,使K562/ADM细胞凋亡率分别增加了Ⅰ-13.27%、Ⅱ-7.03%、Ⅲ-20.24%、Ⅳ-11.75%,使MCF-7/ADM细胞凋亡率分别增加了Ⅰ-6.3%、Ⅱ-3.67%、Ⅲ-8.6%、Ⅳ-3.48%。结论:中药功劳木的4种不同工艺提取物能够不同程度的逆转肿瘤细胞的MDR,抑制肿瘤细胞膜上P-gp的“药泵”功能,增加耐药细胞内药物浓度,有望成为肿瘤多药耐药逆转剂的候选药物。     

姜黄素逆转P—gp介导卵巢癌多药耐药机制的研究

目的探讨姜黄素对P糖蛋白（P—gP）介导的卵巢癌多药耐药的逆转作用及其可能机制。方法采用二苯基溴化四氮唑蓝（MTT）法检测人卵巢癌癌细胞株加药后的增殖,碘化丙啶（PI）染色法检测细胞凋亡率,western blot法检测P—Akt和P-gP的表达量。结果姜黄素合用顺铂处理细胞（OVCAR-3／DDP细胞株）48h,顺铂的浓度在0．05—5μg／ml时,加入姜黄素25μmol／L,耐药细胞生存率下降明显（P〈0．05）,尤以顺铂0．25μg／ml和姜黄素25μmol／L作用时耐药细胞生存率下降最明显。单用顺铂组细胞的凋亡率为（13．2±2．5）％,采用在顺铂基础上联合使用姜黄素后细胞凋亡率为（21．8±3．5）％,与单独使用顺铂相比,顺铂与姜黄素联合使用诱导细胞凋亡的作用显著增强（P〈0．05）。与单用顺铂0．25μg/ml相比,联合使用姜黄素后p-Akt和P-gP的表达量明显降低（P〈0．05）,2组间Akt的表达量差异无统计学意义（P〉0．05）。结论姜黄素不增加顺铂对OVCAR-3细胞毒性作用;对于OVCAR-3／DDP细胞株,姜黄素明显增加顺铂细胞毒性;姜黄素明显抑制了p-Akt和P—gP蛋白的表达。姜黄素可能通过抑制Akt信号通路降低P—gP的表达进而逆转多药耐药。     

和厚朴酚对U937/ADR细胞系耐药逆转作用及其机制研究

目的 探讨和厚朴酚（HNK）对白血病细胞U937阿霉素（ADR）耐药细胞系U937/ADR多药耐药逆转作用及其机制。方法 以大剂量（IC₅₀）ADR短时间诱导方法,构建U937/ADR细胞系。以低浓度HNK（IC₂₀）与不同化疗药物联合作用于U937/ADR细胞系,检测其对不同化疗药物耐药逆转倍数。罗丹明123检测药物外排功能;荧光定量PCR（FQ-PCR）和Western blotting检测不同浓度HNK对U937/ADR细胞系核转录因子-κB(NF-κB)和耐药相关基因MDR1及其蛋白P-糖蛋白（P-gp）表达的影响;ELISA法检测NF-κB亚单位p65（NF-κB p65）的DNA结合活性。结果 成功构建了白血病多药耐药细胞系U937/ADR,对ADR耐药指数为亲代U937细胞的11倍。6.5 μg/mL HNK可以逆转U937/ADR对ADR的耐药,逆转倍数为2.20倍。HNK能够浓度依赖性地下调U937/ADR细胞NF-κB、MDR1 mRNA和P-gp表达,抑制NF-κB p65的活性。结论 HNK能有效逆转U937/ADR多药耐药,其机制可能与抑制NF-κB p65活性、下调MDR1和P-gp表达有关。     

功劳木组分F_6逆转白血病MDR的作用和机制

目的:背景与目的从中药功劳木中提取、分离出来的异喹啉类生物碱组分(Fraction 6,F6),具有抗病毒、抗炎、降血压等生理活性。近年有文献报道异喹啉类生物碱具有一定的逆转肿瘤细胞耐药的作用。本文以白血病多药耐药细胞(K562/ADM)为对象来研究F6逆转肿瘤多药耐药性(Mu ltidrug resistance,MDR)的效果及作用机制,以寻找具有多药耐药逆转活性的新型中药。方法:采用MTT法检测F6及阿霉素(Adriamyc in,ADM)对K562/S和K562/ADM细胞增殖的抑制作用;RT-PCR法检测F6对耐药肿瘤细胞MDR1基因mRNA表达的影响;流式细胞仪分析细胞内罗丹明123(Rhodam ine123,Rh123)浓度,以检测F6对肿瘤细胞膜P糖蛋白(P-glycoprote in,P-gp)泵功能的影响;免疫组化方法检测F6对肿瘤细胞膜P-gp表达水平的影响;流式细胞仪检测F6对肿瘤细胞凋亡的作用。结果:10 mg/L为F6的无毒剂量;ADM对K562/S和K562/ADM细胞的IC50分别为(1.68±0.08)mg/L和(80.25±1.06)mg/L;无毒剂量F6与ADM联合应用后对K562/S和K562/ADM细胞的IC50分别为(1.09±0.07)mg/L和(16.68±0.72)mg/L,此剂量F6使K562/ADM细胞的IC50下降4.81倍;无毒剂量的F6应用前后,K562/ADM细胞MDR1基因表达水平和细胞膜P-gp表达水平无明显差异;Rh123蓄积试验中无毒剂量的F6应用后使K562/ADM细胞内Rh123浓度由F6应用前的29.21%升高到85.35%,Rh123外排试验中无毒剂量的F6应用后使K562/ADM细胞内Rh123浓度由F6应用前的27.19%升高到59.22%;凋亡检测结果显示无毒剂量的F6使K562/ADM细胞凋亡率升高3.82倍。结论:F6能有效逆转白血病细胞的MDR;F6逆转白血病MDR的机制为通过抑制肿瘤细胞膜上P-gp的药泵功能,增加耐药细胞内化疗药物浓度逆转耐药性,而不是抑制MDR1基因和P-gp表达。     

Ligustrazine as a salvage agent for patients with relapsed or refractory non-Hodgkin’s lymphoma

Background The prognosis is poor for patients with relapsed or refractory non-Hodgkin＇s lymphoma （NHL）. The main reason for poor prognosis is multidrug resistance （MDR）, for which the main phenotype is overexpression of P-glycoprotein （P-gp）. This study explored the efficacy of ligustrazine as a salvage agent in patients with relapsed or refractory NHL, and the relationship to P-gp expression. Methods Sixty patients were randomized to a reversal agent group, receiving ligustrazine plus chemotherapy, and a control group, receiving chemotherapy alone. Flow cytometry was performed to evaluate P-gp expression. Results In the 56 patients we were able to evaluate, there was no statistically significant difference in progression-free survival （PFS） in the two groups （P=0.0651）, but the reversal agent group had a higher overall response rate （ORR） than did the control group （P=0.048）. Forty-one of 56 patients had P-gp（＋） tumor cells. Among these patients, six of eighteen patients in the reversal agent group and in the control group had complete remission or complete remission/unconfirmed （CR＋CRu） reflecting a significant advantage in the reversal agent group （P=0.048）. Patients with P-gp（＋） tumor cells in the reversal agent group had a higher overall response rate （ORR） than did the control group （11/18 vs. 6/23, P=0.024）. Kaplan-Meier Survival curve and log-rank test demonstrated that patients with P-gp（＋） tumor cells in the reversal agent group had longer progression-free survival than did the control group （P=0.0464）. A small number of patients who received ligustrazine had a decrease in blood pressure. Conclusion Ligustrazine as a salvage agent in combination with chemotherapy can elevate response rate, prolong PFS with manageable toxicity, and correlate with P-gp expression in relapsed or refractory NHL.     

X射线照射后鼻咽癌细胞多药耐药基因的表达

目的 通过检测射线照射前后鼻咽癌CNE1细胞多药耐药基因(mdr1基因)及其编码产物P糖蛋白(P-gp)的表达和功能为临床鼻咽癌放化疗顺序提供参考。方法 利用RT-PCR、Western blotting和流式细胞仪检测射线照射前后CNE1细胞的mdr1基因和P-gp的表达及对柔红霉素的外排功能。结果 鼻咽癌CNE1细胞射线照射前mdr1基因、P-gp不表达;照射后较长时间内mdr1基因、P-gp均明显表达;对柔红霉素的摄取较射线照射前低。结论 鼻咽癌CNE1细胞射线照射后化疗敏感性降低,提示临床对于中晚期鼻咽癌的治疗应考虑先化疗再放疗即诱导化疗的治疗方案。     

X射线照射后鼻咽癌细胞多药耐药基因的表达

目的 通过检测射线照射前后鼻咽癌CNE1细胞多药耐药基因(mdr1基因)及其编码产物P糖蛋白(P-gp)的表达和功能为临床鼻咽癌放化疗顺序提供参考。方法 利用RT-PCR、Western blotting和流式细胞仪检测射线照射前后CNE1细胞的mdr1基因和P-gp的表达及对柔红霉素的外排功能。结果 鼻咽癌CNE1细胞射线照射前mdr1基因、P-gp不表达；照射后较长时间内mdr1基因、P-gp均明显表达；对柔红霉素的摄取较射线照射前低。结论 鼻咽癌CNE1细胞射线照射后化疗敏感性降低，提示临床对于中晚期鼻咽癌的治疗应考虑先化疗再放疗即诱导化疗的治疗方案。     

Expression of the human multidrug resistance gene mdr1 in leukemic cells and its application in studying P-glycoprotein antagonists

Objective To explore the role of endothelin (ET) in the pathogenesis of exercise-induced asthma (EIA), we investigated the effects of ET(B) receptor antagonists, ET-1 (11-21)fragment and N-cis-2,6-dimethylpi-peridinocardonyl-L-γ-methylleucyl-D-1-methoxycarbonyl tryptophanyl-D-norleucine (BQ788) on broncho-constriction elicited by isocapnic hyperpnea in guinea pigs. Methods Eighteen pathogen-free Hartley guinea pigs were randomly divided into three groups. A: normal saline (NS) inhalation control group (n=6), B: BQ788 group (n=6), and C: ET-1(11-21) fragment group (n=6). Guinea pigs were anesthetized with pentobarbital sodium. After measuring the basal value of lung resistance (R[L]) and dynamic compliance of the respiratory system (Cdyn), NS (0.96 ml), BQ788 (9 nmol) and ET-1(11-21)fragment (9 nmol) were inhaled. A rodent respirator with a dry 5%CO(2)-95%O(2) mixture at room temperature provided mechanical ventilation (V[T] 8 ml/animal, 100 breaths/min) for 5 min. R[L] and Cdyn of the 3 groups were measured again after isocapnic hyperpnea challenge. Results In the control group, isocapnic hyperpnea of dry gas elicited a marked increase in R[L] and decrease in Cdyn. R[L] and Cdyn of the guinea pigs from BQ788 group and ET-1(11-21)fragment group did not change significantly. Conclusion It was demonstrated that selective ET(B) receptor antagonists, ET-1(11-21) fragment and BQ788, inhibited the bronchoconstriction induced by isocapnic hyperpnea in guinea pigs. The data showed that ETs are potent constrictors of guinea pig airway smooth muscle via a direct effect on ET receptors. It was suggested that ET receptor antagonists, especially ET(B) receptor antagonist, might be beneficial in preventing EIA.     

Thapsigargin逆转K562/A02细胞多药耐药性的实验研究

目的 探讨内质网Ca^2 -ATP酶抑制剂thapsigargin对白血病多药耐药细胞株K562／A02化疗敏感性的影响。方法 用MTT比色法检测K562／A02细胞耐药性、thapsigargin的增殖抑制活性及其对K562／A02细胞化疗敏感性的影响；丫啶橙(AO)／溴化乙锭(EB)染色荧光显微镜观察thapsigargin处理后K562／A02细胞形态改变；流式细胞仪(FCM)检测P-糖蛋白(P-gp)表达；荧光显微镜检测Pgp功能。结果 ①thapsigargin对K562和K562／A02细胞的增殖抑制活性呈剂量和时间依赖性，K562／A02细胞较K562细胞对thapsigargin更敏感，thapsigargin诱导K562／A02细胞呈现典型的凋亡细胞形态学改变。②K562／A02细胞对阿霉素(ADM)、柔红霉素(DNR)、长春新碱(VCR)、依托泊苷(VP-16)、高三尖杉酯碱(HHT)和米托蒽醌(MXT)均出现不同程度的耐药性；thapsigargin抑制K562／A02细胞P-gP功能而对其表达无影响，thapsigargin能增加K562／A02细胞对ADM、DNR、VCR、VP-16、HHT和MXT的化疗敏感性。结论 Thapsigargin能诱导白血病多药耐药细胞株K562／A02细胞凋亡并能部分逆转K562／A02的多药耐药性；thapsigargin的多药耐药逆转功能可能与其凋亡诱导作用和抑制PgP功能有关。     

Retroviral-mediated transfer and functional expression of multidrug resistance gene in human placenta mesenchymal stem cells

Background Most of gynecologic malignancies are sensitive to chemotherapy. Myelosuppression is the main dose-related toxicity of many chemotherapeutic drugs. The human multidrug resistance （mdrl） gene is well known for its ability to confer drug resistance. This study aimed to explore the feasibility of expression and resistance of mdrl gene transduction into human placenta mesenchymal stem cells （P-MSCs） by retrovirus vector. Methods Human P-MSCs were isolated from trypsin-digested term placentas, and their immunophenotypes and differentiation potential were evaluated. Human P-MSCs were transduced by reconstructed retroviral vector containing the mdrl gene and green fluorescent protein （GFP） reporter gene. The integration and expression of the mdrl gene were observed indirectly by the expression of GFP, and fluorescence-activated cell sorter was used to evaluate the functional activity of permeability glycoprotein （P-gp） encoded by the mdrl gene. The stimulating test was made in vitro to show pleiotropic drug resistance of transfected cells. Results The isolated, cultured and expanded P-MSCs expressed stem cell markers such as CD29, CD44 and CD73, and showed osteogenic and adipogenic differentiation potentials under appropriate conditions. The expression of P-gp in the non-transfected P-MSCs cells was （0.4±0.1）%, but increased to （28.1±4.7）% after gene transfection （P〈0.01）. And positive staining of P-gp located mainly at cell membrane and cytoplasm. Accumulation and extrusion assays showed that P-gp expressed by the transfected cells had pump-functional activity and could efflux daunomycin out of cells. The analysis of cell survival confirmed that transfected P-MSCs had a characteristic of multidrug resistance with a significant increase in the resistance to anticancer agents. Conclusions Transfer and expression of human mdrl gene mediated by retrovirus vector conferred P-MSCs drug resistance. It might provide a new alternative to chemoprotection strategies.     

复方五味子素B逆转多药耐药性人结肠癌细胞THC-8307

目的探讨复方五味子素B(γSC)逆转人结肠癌细胞THC-8307/OXA多药耐药的作用机制。方法采用四甲基偶氮唑蓝(MTT)法测定药物对细胞的毒性作用;通过Western blot法分析药物对THC-8307细胞P糖蛋白(P-gp)多药耐药相关蛋白表达的影响。结果γSC在浓度<12.5 mg/L时对THC-8307和THC-8307/OXA无毒性作用,12.5 mg/L的γSC可明显逆转THC-8307/OXA耐药细胞的耐药性。THC-8307细胞不表达P-gp,THC-8307/OXA细胞P-gp高表达。加入γSC后THC-8307/OXA细胞P-gp蛋白的表达明显下降。结论γSC具有逆转THC-8307/OXA的作用,主要通过下调肿瘤多药耐药细胞内P-gp的表达逆转耐药。     

青蒿素对乳腺癌多药耐药MCF-7/ADR细胞的逆转作用

目的探讨青蒿素在乳腺癌多药耐药中的应用。方法采用MTT法观察青蒿素联合阿霉素(ADR)对乳腺癌耐药株MCF-7/ADR细胞生长增殖的影响;应用流式细胞技术测定青蒿素联合ADR对MCF-7/ADR细胞P-糖蛋白(P-glycoprotein,P-gp)表达的影响。结果 10、20、40μmol/L青蒿素实验组的细胞耐药逆转倍数分别为1.53、1.90和3.62倍。青蒿素联合ADR可抑制MCF-7/ADR细胞膜P-gp蛋白的表达,0、10、20、40μmol/L青蒿素作用后的细胞表面P-gp表达阳性率分别为(33.41±4.63)%、(23.07±5.48)%、(21.82±3.87)%和(16.62±1.27)%,组间比较差异均有统计学意义(均P<0.05);各组细胞内总P-gp的表达水平分别为(37.19±5.16)%(、35.30±4.77)%(、37.45±5.19)%和(34.98±3.50)%,各组间差异无统计学意义(P>0.05)。结论青蒿素与ADR同共作用于MCF-7/ADR细胞,使细胞对ADR的敏感性增高,青蒿素具有部分逆转MCF-7/ADR细胞耐药的作用,其逆转作用机制可能是通过影响细胞质和细胞膜之间的P-gp交换,降低细胞膜上P-gp表达水平,提高药物在细胞内的聚集,增强药物对肿瘤细胞的杀伤作用。     

五味子乙素对转染多药耐药1基因的MCF-7细胞的多药耐药逆转作用

目的 探讨五味子乙素(SchB)对转染多药耐药1基因(MDR1)的人乳腺癌细胞MCF-7的多药耐药逆转作用及相关机制。方法 将人MDR1基因导入MCF-7细胞,形成耐药细胞株MCF-7／MDR1;用该细胞株为模型评价SchB的体外逆转多药耐药作用,用MTT法进行化疗药物单独或与SchB联合作用时对耐药细胞的IC50比较,计算逆转倍数。结果 转染细胞MCF-7／MDR表现为P糖蛋白高表达,对阿霉素、长春新碱、紫杉醇、高三尖杉酯的抗药性均增加;SchB(25μmol／L)显著减少阿霉素、长春新碱、紫杉醇和高三尖杉酯对MCF-7／MDR细胞的IC50,逆转倍数达6．03-23．94倍;SchB(25μmol／L)使MCF-7／MDR细胞对若丹明123的胞内积聚增加约5倍。效果与维拉帕米10μmol／L浓度时相当;但SchB(25μmol／L)不影响MCF-7／MDR细胞的P-糖蛋白表达。结论 SchB能有效逆转转染MDR1的MCF-7细胞的多药耐药,其机制可能是抑制了P-糖蛋白的药物外排生物学活性。     

微流控芯片技术分析细胞外酸性环境对肿瘤细胞P-糖蛋白表达、活性及其介导的道诺霉素细胞毒性的影响

目的 采用微流控芯片技术分析细胞外酸性环境对肿瘤细胞P-糖蛋白(P-gp)表达、活性及其介导的道诺霉素细胞毒性的影响。方法 在微流控芯片上将A549细胞分为实验组和对照组,实验组用pH为6.6酸性细胞培养液处理,对照组用pH为7.4中性培养液常规培养,芯片上进行细胞免疫荧光技术分析P-gp表达,罗丹明123外排实验评价P-gp活性,细胞存活/凋亡荧光染色法分析道诺霉素的细胞毒性。结果 微流控芯片可为A549细胞生长提供适宜的微环境,细胞在72 h后融合度能达到90%以上。酸性细胞培养液处理对P-gp表达未产生显著影响,但可显著增强P-gp活性,处理时间
6 h时A549细胞P-gp活性达到峰值。酸性细胞培养液处理6 h后道诺霉素细胞毒性效率显著降低,在P-gp抑制剂维拉帕米协同作用下道诺霉素细胞毒性得到逆转。结论 微流控芯片技术可缩短分析时间,降低试剂耗量,为进一步认识肿瘤多药耐药机制和高效肿瘤耐药逆转剂筛选提供新的技术平台。     

逆转胶囊对人乳腺癌MCF-7/ADR细胞中P-gp和MRP表达的影响

目的:检测逆转胶囊对乳腺癌耐药相关蛋白表达的影响,探讨其逆转乳腺癌多药耐药的作用机制。方法:流式细胞术、免疫印迹技术(Western-blot)检测逆转胶囊作用前后MCF-7/ADR细胞表面P-糖蛋白(P-gp)、多药耐药相关蛋白(MRP)的表达。结果:逆转胶囊能显著抑制MCF-7/ADR细胞表面P-gp的表达,并可诱导MRP表达下降,其作用随血药浓度增加和作用时间的延长而增强。结论:逆转胶囊逆转乳腺癌多药耐药的机制与下调P-gp和MRP的表达有关。     

氨氯地平衍生物CJX1对K562/DOX细胞阿霉素耐药的逆转作用

目的:研究氨氯地平衍生物CJX1对K562/DOX细胞阿霉素耐药的逆转作用.方法:应用流式细胞仪和MTT法观察了CJX1对K562/DOX细胞P-糖蛋白(P-gp)的抑制作用及对K562/DOX细胞阿霉素耐药的逆转作用.结果:CJX1能剂量相关性地增加K562/DOX细胞内罗丹明123(Rh 123)的累计,明显抑制P-gp 介导的Rh 123外排,显著增强阿霉素对K562/DOX细胞的细胞毒作用,增加K562/DOX细胞内阿霉素水平.结论:氨氯地平衍生物CJX1能显著抑制P-gp的外排功能,逆转K562/DOX细胞的多药耐药性.     

肾母细胞瘤术前化疗前后P-糖蛋白表达的变化及临床意义

目的：探讨肾母细胞瘤术前化疗耐药性的生物学特性及与疗效相关性。方法：对18例未术前化疗和经不同疗程术前化疗病理档案,以JSD-单克隆抗体对肾母细胞瘤组织多药耐药蛋白(P-glycoprotein,P-gp)进行免疫组织化学,检测P-gp在术前化疗不同疗程的表达,确定其耐药性;同时对15例资料记录完整、术前化疗＞5周的小儿肾母细胞瘤,通过B超随访测量术前化疗不同疗程肿瘤大小,了解其疗效及与耐药性的相关性。结果：术前化疗后的肿瘤细胞P-gp表达比未经术前化疗的肿瘤细胞强,而术前化疗疗程越长,肿瘤细胞P-gp表达越强,疗效降低。结论：术前化疗4周后疗效降低与瘤组织对化疗药物耐药性明显增强有关,免疫组织化学检测P-gp可为制定或更改肾母细胞瘤术前化疗方案及术后化疗方案提供有用的依据。     

Inducing effects of macrophage stimulating protein on the expansion of early hematopoietic progenitor cells in liquid culture

Background Macrophage stimulating protein （MSP） is produced by human bone marrow endothelial cells. In this study we sought to observe its effects on inducing the expansion of early hematopoietic progenitor cells which were cultured in a liquid culture system in the presence of the combination of stem cell factor （SCF）, interleukin 3 （IL-3）, interleukin 6 （IL-6）, granulocyte macrophage-colony stimulating factor （GM-CSF）, erythropoietin （EPO） （Cys） and MSP or of Cys and bone marrow endothelial cell conditioned medium （EC-CM）. Methods Human bone marrow CD34^＋ cells were separated and cultured in a liquid culture system for 6 days. Granulocyte-macrophage colony forming unit （CFU-GM） and colony forming unit-granulocyte, erythrocyte, macrophage, megakaryocyte （CFU-GEMM） were employed to assay the effects of different treatment on the proliferation of hematopoeitic stem/progenitor cells. The nitroblue tetrazolium （NBT） reductive test and hoechest 33258 staining were employed to reflect the differentiation and apoptosis of the cells respectively. Results MSP inhibited the proliferation of CFU-GM and CFU-GEMM in semi-solid culture and the inhibitory effect on CFU-GEMM was stronger than on CFU-GM. MSP inhibited the differentiation of early hematopoietic progenitor cells induced by hematopoietic stimulators. Bone marrow （BM） CFU-GEMM was 2.3-fold or 1.7-fold increase or significantly decreased in either Cys＋EC-CM, Cys＋MSP or Cys compared with 0 hour control in liquid culture system after 6 days. Conclusion MSP, a hematopoietic inhibitor, inhibits the differentiation of early hematopoietic progenitor cells induced by hematopoietic stimulators and makes the early hematopoietic progenitor cells expand in a liquid culture system.     

五味子乙素逆转膀胱肿瘤多药耐药的实验研究

目的研究五味子乙素对膀胱肿瘤T24/ADM细胞多药耐药的逆转作用。方法 MTT法测定半数抑制浓度IC50和逆转倍数RI,流式细胞仪测定细胞内罗丹明的浓度。结果五味子乙素可以明显增加阿霉素对膀胱肿瘤T24/ADM细胞的细胞毒作用（P〈0.05）,逆转指数为4.11,五味子乙素明显抑制了细胞内罗丹明的外排（P〈0.05）。结论五味子乙素明显抑制了膀胱肿瘤细胞的多药耐药,其机制可能与其抑制P-gp蛋白的外排有关。