^99Tc^m-亚锡葡庚糖酸钠结合GGC序列监测基因治疗的实验研究

目的 构建以金属结合肽（双甘氨酰半胱氨酸,即GGC序列）为核素报告基因、人VEGF165为治疗基因的重组腺病毒载体,以99Tcm-GH为报告探针,探讨该报告系统监测治疗基因表达的可行性.方法 pcDNA3-VEGF165质粒线性化后,将金属结合肽GGC序列连于VEGF165基因C端,通过内部核糖体切入位点（IRES）连接增强型绿色荧光蛋白（EGFP）,构建重组腺病毒载体Ad5-VEGF165GGCmotif-IRES-EGFP（Ad5-VIE）,同时构建腺病毒包装EGFP（Ad5-EGFP）为对照.以不同感染复数（MOI=0,10,25,50,100）Ad5-VIE感染大鼠骨髓间充质干细胞（MSC）后,用99Tcm-GH为报告探针,研究感染细胞摄取动力学（30,60,90和120 min）情况,以检测GGC序列在MSC中的表达,并与实时定量PCR、Western-blot蛋白印迹、免疫组织化学等方法鉴定的VEGF165表达进行对比分析.通过荧光显微镜及实时定量PCR检测EGFP在细胞中的表达.采用SPSS 13.0软件进行统计学处理,组间比较运用独立样本成组t检验、q检验和直线（Pearson）相关分析.结果 以Ad5-VIE感染MSC后,不同MOI摄取实验结果示细胞对99Tcm-GH的摄取率随病毒MOI的增加而逐渐增加（r2=0.86,P＜0.05）,并且在MOI=100时达到（7.94±0.75）%;不同时间摄取实验示随99Tcm-GH孵育时间延长,细胞摄取率逐步增高,至120 min时达到（7.72±0.22）%.Ad5-VIE感染组与Ad5-EGFP感染组摄取率在各个不同时间点差异均有统计学意义（t=15.10～54.92,P均＜0.05）.在mRNA水平上,VEGF165及EGFP表达均随病毒MOI增加而增加（r2=0.99,P＜0.05）.不同MOI下细胞对99Tcm-GH的摄取与VEGF165蛋白表达呈较好的相关性（r2=0.90,P＜0.05）.免疫组织化学检查结果表明人VEGF165目的 基因在MSC中成功表达.荧光显微镜下可以观测到被感染细胞中的EGFP蛋白.结论 成功构建的重组腺病毒系统Ad5-VIE感染MSC对99Tcm-GH的摄取与VEGF165表达呈正相关.以GGC多肽为报告基因可以监测治疗基因VEGF165的表达,为核素报告基因显像提供了理论依据.     

重组质粒hTSHR转染低分化甲状腺癌细胞株后对摄碘能力及特异性基因表达的影响

Objective To investigate the changes of iodide uptake and the expression of thyroidspecific genes in poorly differentiated follicular thyroid carcinoma (FTC) cells after transfection of human TSH receptor (hTSHR) gene in vitro. Methods The recombinant eukaryotic expression plasmid PcDNA3. 1/hTSHR-cDNA was transformed into DH5a bacterial for amplification and then the recombinant plasmid was extracted. The recombinant was identified with PCR amplifying, restriction enzyme digestion analysis and DNA sequencing. The recombinant plasmid pcDNA3.1/hTSHR was transfected into FTC-133 cell line by lipofectin methodin vitro. Immunofluorescence, iodide uptake studies and real time-PCR were applied to detect target protein expression. Statistical analysis was performed with t-test using SPSS 13. 0 software. Results Kpn Ⅰ and Xba Ⅰ restriction enzyme digestion, PCR amplifying and DNA sequencing confirmed that pcDNA3. 1/hTSHR was successfully constructed. After transfection of the recombinant plasmid pcDNA3. 1/hTSHR-cDNA and the stimulation of hTSH, the tumor cells displayed the expression of hTSHR protein at cell surface and cytoplasm. The iodine uptake in pcDNA3. 1/hTSHR transfected cells was 2. 9 times higher than that of control(pcDNA3.1(+) transfected cells) group(t = 28.63, P ＜0. 01). The expression of TSHR,NIS, TPO and Tg (mRNA levels) in pcDNA3. 1/hTSHR transfected cells were also significantly elevated by 1.74 (t =5.959, P＜0.01), 7.2 (t =3.807,P＜0.05), 2.88 (t=4.769,P＜0. 01) and 2.67 times (t=6.388,P ＜0.01) respectively compared to those of the control group. Conclusion The study demonstrates that iodide uptake may be reactivated by hTSHR receptor gene transfection in poorly differentiated FTC cell.     

利用报告基因rNIS监测大鼠骨髓间充质干细胞移植大鼠心肌的可行性研究

Objective To investigate the feasibility of rat sodium/iodide symporter (rNIS) as a reporter gene monitoring rat bone marrow mesenchymal cells (rBMSC) transplanted to rat myocardium in vivo.Methods Recombinated adenovirus vector was constructed by rNIS/enhanced green fluorescence protein (EGFP) (Ad-rNIS/EGFP).rBMSC transfected by Ad-rNIS/EGFP were studied using fluorescence microscope.Fifteen rats were transplanted with rBMSC and randomly divided into three groups:rNIS group (with rNIS transfection), blocked group (with rNIS transfection) by oral intake of perchloric sodium before planar imaging(GE Millennium MPR SPECT), and control group (without rNIS transfection).All rats underwent 99Tcm-pertechnetate planar imaging.The biological distribution of 99Tcm-pertechnetate was studied.The expressions of rNIS gene and protein in myocardium were measured by real time polymerase chain reaction (PCR) and western blot, respectively.The expressions of CD29, CD44, CD90, CD11b, CD34 and CD45 were measured by immunohistochemistry.Results rBMSC transfected by Ad-rNIS/EGFP showed EGFP expression under fluorescence microscope.The transplanted rat myocardium could be visualized on 99Tcm-pertechnetate planar imaging in rNIS group.The relative uptake ratio( Rheart/Rhmb, RUR) was 6.7 ±0.4.RUR in control group (3.0 ±0.2) was lower than that in rNIS group (t =2.78, P=0.03).The percentage injection dose per gram of tissue (% ID/g) of the transplanted myocardium was 60.2 ± 20.8 in rNIS group,which was higher than that (2.5 ± 0.4) % ID/g of control group ( t = 7.13, P＜0.001 ).rNIS gene and protein were highly expressed in transplanted myocardium in rNIS group but less expressed in control group.The expressions of CD29, CD44 and CD90 were positive, CD45 and CD45 negative CD11b mildly positive in the myocardium transplanted with infective rBMSC.Conclusion rNIS can efficiently monitor rBMSC transplanted to rat myocardium.     

99Tcm-MIBI显像评价非小细胞肺癌三维适形放疗疗效的临床研究

Objective To explore whether the degree of 99Tcm-methoxyisobutylisonitrile (MIBI) uptake in non-small cell lung cancer (NSCLC) could be correlated with the treatment response to three-dimensional conformal radiotherapy.Methods A total of 102 patients with NSCLC were studied with 99Tcm-MIBI SPECT before radiotherapy.The patients were classified by a follow-up CT as responders (complete or partial remission) and non-responders (stable or progressive disease).After intravenous administration of 740 MBq 99Tcm-MIBI, SPECT imaging at 10-30 min (early) and 2-3 h (delayed) were performed.Region of interest (ROI) was placed over the tumors and contralateral normal lung tissue.The uptake ratio of tumor to contralateral normal lung (T/N) was obtained from both early (ER) and delayed (DR) SPECT images.The retention index (RI) was measured as:RI = (DR - ER)/ER×100%.Statistical analysis was performed by two independent-sample t-test and Mann-Whitney U test using software SPSS 13.0.Results 99Tcm-MIBI uptake was significantly higher in responders than in non-responders:2.36 ±0.17 vs 1.82 ±0.14 (ER) and 2.48 ± 0.20 vs 1.94 ± 0.16 (DR), respectively (t = - 13.1,- 12.7, both P＜ 0.05).The median RI in the responders group was also significantly higher than that in the non-responders group (6.60% vs 5.13%, z = - 6.83, P ＜ 0.05).Conclusion ER, DR and RI of 99Tcm-MIBI SPECT might be useful to estimate the treatment response to three-dimensional conformal radiotherapy in patients with NSCLC.     

Expression of C2A domain of synaptotagmin Ⅰ fusion protein and its imaging in the ischemia-reperfusion rat model

Objective To evaluate myocardial apoptosis with 99Tcm-C2A-GST myocardial imaging using the recombined C2A domain of Synaptotagmin Ⅰ by gene engineering. Methods ( 1 ) The C2A gene was inserted into the prokaryotic glutathione S-transferate (GST) fusion protein expression plasmid pGEX-6P-1. The recombinant plasmid was transformed into E. coli BL21. C2A-GST fusion protein was purified after BL21 was induced with isopropyl-β-D-1-thiogalactopyranoside (IPTG). (2)The activity of fusion protein was identified by cell binding test with fluorescein-5-isothiocyanate (FITC)-C2A-GST. (3) The C2A-GST fusion protein was labeled with 99Tcm using 2-iminothiophene hydrocoride method. Radiochemical purity was determined with thin layer chromatography. (4)99Tcm-C2A-GST (7.4 MBq) was injected to ischemia-reperfusion rat models through tail vein. The image was acquired with SPECT at 1 h after injection, and then hearts were removed, rinsed with saline and dyed with triphenyl tetrazolium coride (TTC). The ischemic myocardium was separated from the viable myocardium and was weighted. Its radioactivity was measured by gamma counting. The difference of uptake of radiotracer between ischemic myocardium and normal myocardium was compared using percentage activity of injected dose per gram of tissue ( % ID/g) with standard deviation. SPSS 12.0 and t-test were used for data analysis. Results ( 1 ) C2A-GST fusion protein wassuccessfully expressed and its relative molecular weight was 3.8 × 104. (2) FITC-C2A-GST binding to apoptotic cells could be observed by fluorescent microscopy. (3) The radiochemical purity of 99Tcm-C2A-GST was (98.90 ±0.43)%. (4)The imaging studies showed that there was focal uptake of radioactivity in the ischemic myocardium. In vitro uptake of 99Tcm-C2A-GST was (2.41 ±0.32) % ID/g by the ischemic myocardium, however 99Tcm-C2A-GST-N-hydroxysuccinimide (C2A-GST-NHS) was (0. 82 ± 0. 24) % ID/g. There was statistically significant difference between those two groups (t = 10. 6, P ＜0.01 ). Conclusion The C2A domain of Synaptotagmin Ⅰ expressed by gene engineering can be used as the tracer for noninvasive detection of ischemic myocardium in the ischemia-reperfusion rat model.     

双功能制剂99Tcm-Gd-DTPA-DG的制备及在荷瘤裸鼠体内的生物分布

Objective To evaluate the stability and biodistribution of a novel SPECT-MRI bi-functional agem 99Tcm-Gd-DTPA-DG in tumor-bearing nude mice. Methods DTPA-DG was synthesized and then conjugated with Gd2O3 to generate Gd-DTPA-DG. The tumor-bearing nude mice were scanned by MRI to evaluate the tumor targeting ability of Gd-DTPA-DG. The orthogonal experiment was applied to optimize pH value of reaction medium and reaction temperature. The radiolabeling efficiency was measured by thin layer chromatography. The distribution of 99Tcm-Gd-DTPA-DG in nude mice was evaluated by scintigrapy in vivo. The % ID/g was measured at different time after intravenous injection of 99Tcm-Gd-DTPA-DG. Results The tumor was significantly enhanced by Gd-DTPA-DG with MRI. The radiochemical purity of 99Tcm-Gd-DTPADG was about 98.5% and remained 96.2% at room temperature for 6 h. The tumor was well visualized by 99TcmGd-DTPA-DG SPECT at 2 h after injection. The tumor uptake was (1.48 ±0.12) %ID/g, and the rumor to muscle radioactivity ratio was 2.91. Conclusions MRI contrast of Gd-DTPA-DG may enhance tumor detection. 99Tcm-labeled Gd-DTPA-DG may be useful for tumor imaging and might have a potential role as a SPECT-MRI bi-functional agent.     

利用报告基因rNIS监测大鼠骨髓间充质干细胞移植大鼠心肌的可行性研究

Objective To investigate the feasibility of rat sodium/iodide symporter (rNIS) as a reporter gene monitoring rat bone marrow mesenchymal cells (rBMSC) transplanted to rat myocardium in vivo.Methods Recombinated adenovirus vector was constructed by rNIS/enhanced green fluorescence protein (EGFP) (Ad-rNIS/EGFP).rBMSC transfected by Ad-rNIS/EGFP were studied using fluorescence microscope.Fifteen rats were transplanted with rBMSC and randomly divided into three groups:rNIS group (with rNIS transfection), blocked group (with rNIS transfection) by oral intake of perchloric sodium before planar imaging(GE Millennium MPR SPECT), and control group (without rNIS transfection).All rats underwent 99Tcm-pertechnetate planar imaging.The biological distribution of 99Tcm-pertechnetate was studied.The expressions of rNIS gene and protein in myocardium were measured by real time polymerase chain reaction (PCR) and western blot, respectively.The expressions of CD29, CD44, CD90, CD11b, CD34 and CD45 were measured by immunohistochemistry.Results rBMSC transfected by Ad-rNIS/EGFP showed EGFP expression under fluorescence microscope.The transplanted rat myocardium could be visualized on 99Tcm-pertechnetate planar imaging in rNIS group.The relative uptake ratio( Rheart/Rhmb, RUR) was 6.7 ±0.4.RUR in control group (3.0 ±0.2) was lower than that in rNIS group (t =2.78, P=0.03).The percentage injection dose per gram of tissue (% ID/g) of the transplanted myocardium was 60.2 ± 20.8 in rNIS group,which was higher than that (2.5 ± 0.4) % ID/g of control group ( t = 7.13, P＜0.001 ).rNIS gene and protein were highly expressed in transplanted myocardium in rNIS group but less expressed in control group.The expressions of CD29, CD44 and CD90 were positive, CD45 and CD45 negative CD11b mildly positive in the myocardium transplanted with infective rBMSC.Conclusion rNIS can efficiently monitor rBMSC transplanted to rat myocardium.     

99Tcm标记新型RGD环肽在神经胶质瘤动物模型的实验研究

Objective (1) To evaluate the effect of insertion of two 15-amino-4,7,10,13-tetraoxapentadecanoic (2 PEG4 ) linkers into cyclic Arg-Gly-Asp (RGD) Dimer E [c(RGDfK)]2 on receptor binding in vitro, (2) to assess its biodistribution in vivo and (3) to investigate the value of 99Tcm labeled 2PEG4-Dimer for integrin αvβ3-positive tumors imaging.Methods The expression of U87 human glioma cells and integrin αv β3 was determined by immunofluorescence staining.The half-inhibition concentrations (IC50) for 125 I-cyclo (Arg-Gly-Asp-D-Tyr-Lys) (c(RGDyK) ) of c ( RGDyK ), hydrazinonictinamide ( HYNIC )-Dimer and HYNIC-2PEG4-Dimer binding to integrin αvβ3 were measured.99Tcm-HYNIC-Dimer and 99Tcm-HYNIC-2PEG4-Dimer were synthesized using non-SnCl2 formulation.Biodistribution and imaging studies were performed in nude mice bearing human glioma xenografts.The unpaired t test was used for statistical analysis.Results The labeling yield of the two radiotracers was more than 95%, and the radiochemical purity was more than 99% through Sep-Pek C18 cartridge.HYNIC-2PEG4-Dimer had significantly higher binding affinity of integrin αvβ3 than c(RGDyK) and HYNIC-Dimer (IC50 = 0.8 nmol/L, 27 nmol/L and 2.4 nmol/L, respectively).Biodistribution study showed that 99Tcm-HYNIC-2PEG4-Dimer was mainly excreted via the kidney.The tumor uptake of 99Tcm-HYNIC-2PEG4-Dimer was higher than that of 99Tcm-HYNIC-Dimer at 2h post injection ((5.71 ±0.96) and (2.10 ±0.50) % ID/g, t =4.80, P＜0.05).The xenografted tumors were visible at 0.5 h post injection and the image contrast increased with time due to the tracer clearance of the background tissue.Conclusion 99 Tcm-HYNIC-2PEG4-Dimer is a promising radiotracer for integrin αvβ3-positive tumor imaging.     

hNIS基因转染介导Hela细胞移植瘤放射性核素显像和治疗的实验研究

Objective To explore the feasibility of imaging and treatment of cervical cancer xenograft model using 131I mediated by hNIS gene transfection. Methods The cervical cancer xenograft models were established with Hela-NIS( +) cells and Hela cells, respectively. Five Hela-NIS( +) xenograft models and five Hela xenograft models were dynamically imaged at 0.5, 1, 2, 4, 8, 16 and 20 h postinjection of 131I(7.4 MBq). Five Hela-NIS( +) xenograft models were imaged at 0. 5,1,2,4,8,16, 20 and 25 h postinjection of 99TcmO4-(11.1 MBq). Twenty Hela-NIS( +) cervical cancer xenograft models were randomly divided into four groups: Three 131I treating groups and one control group. The therapeutic effects of 131I at threelevels (74,111,148 MBq) were investigated following intraperitoneal injection. Results Hela-NIS( +)human cervical cancer xenografts were established successfully in nude mice. The Hela-NIS( +) xenografts significantly accumulated radioactivity after intraperitoneal injection of 131I, and the radioactivity was persistently present until 20 h postinjection, but Hela xenografts had no radioactive accumulation. The T/B value of the Hela-NIS( +) xenografts reached 17.34 at 8 h postinjection. The imaging with 99TcmO4- showed that the radioactivity was persistently present in Hela-NIS( +) xenografts for almost 25 h. The Hela-NIS( +)xenografts shrinked after 131I treatment. The inhibition ratios of tumor growth in 111 MBq and 148 MBq groups were both significantly higher than that of 74 MBq group (t: 2.74-5.75, P ＜0.05). Conclusions Hela-NIS( +) cervical cancer xenografts in nude mice could persistently accumulate 131I and 99TcmO4- and could be treated successfully with 131 I. 131 I treatment mediated by hNIS gene transfection could be a promising cancer treatment method.     

99Tc-亚甲基二膦酸盐对胶原诱导性关节炎大鼠滑膜及软骨凋亡相关因子的影响

Objective Collagen induced arthritis (CIA) rats is an animal model of human rheuma-toid arthritis (RA). It is widely used in research of the pathogenesis and the therapeutic targets of RA. This paper was to investigate the therapeutic action of 99Tc-methylene diphosphonic acid (MDP) on CIA rats and its effects on the expression of apoptosis associated factor bcl-2 and bax in synoviocytes and articular chon-drocytes. Methods CIA rat models were carried out by subcutaneous injection with bovine collagen Ⅱ and incomplete Freud's adjuvant. Rats were divided into four groups: control group, CIA model group (the CIA rats were infused with physiological saline via tail vein daily), 99Tc-MDP group (the C1A rats were injected with 99Tc-Mi)P 0.04 μg 99Tc/kg via tail vein daily) and methotrexate (MTX) group (the CIA rats were in-jected with MTX 1 mg/kg via tail vein weekly). The signs of arthritis were evaluated by arthritis index (AI) scores. Immunohistochemistry was performed to detect the expression of bcl-2 and bax in synoviocytes and articular chondrocytes. SPSS 13.0 was used for data analysis. Results (1) The signs of arthritis, AI scores and pathological changes of arthrosynovitis in CIA rats were significantly improved by 99Tc-MDP orMTX. (2) The expression of bcl-2 and box in the synoviocytes of CIA model group [(39.30 ± 0.53) %, (27.37 ±2.45)%] was significantly increased compared with control group [(7.56 ± 1. 18)% , (6.14 ± 1.71) % ; q = 46.27, 24.57, all P < 0.001]. In the synovioeytes of 99Tc-M DP group and MTX group, the level of bcl-2 was remarkably decreased [(30.24 ± 2.09) %, (27.25 ± 3.33) %] compared with CIA model group (q = 13.20, 17.56, all P <0.001), while the level of bax was slightly increased and the ratio of bcl-2/bax was significantly decreased. (3)The expression level of bcl-2 and bax in the articular chondro-cytes of CIA model group [(20.20 ± 2.78) %, (36.40 ± 1.67) %] was significantly higher than control group [(9.91±4.09)%, (6.71 ±3.50)%; q=10.51, 37.01, allP<0.001]. Compared with CIA model group, the expression level of bcl-2 in articular chondrocytes of 99Tc-MDP group [(26. 58 ± 2. 52) %] and MTX group [(27.06 ± 1.92) %] was remarksbly increased [(24.26 ± 2.75) %, (23.53 ± 0.74) % ; q = 6.53, 7.01, all P < 0.001]. And the expression level of bax was significantly decread (q = 15.12, 16.04, all P <0. 001) and the ratio of bcl-2/bax was significantly increased. Conclusions The ab-normal expression of apoptosis associated factor bcl-2 and bax in synoviocytes and articular chondrocytes was closely related to the occurrence and progression of signs in CIA rats. 99Tc-MDP could improve the signs of arthritis, meanwhile regulate the expression of bcl-2 and bax in synoviocytes and articular ehondrocytes, suggesting that one of the therapeutic mechanisms of 99Tc-MDP might be related to stimulated synoviocytes apoptosis and reduced articular chondrocytes apoptosis.     

The plasma protein binding of HIDA

By using Sephadex gel column chromatography to separate substances into their various components according to molecular weight, we have investigated the effect of incubating several brands of HIDA in plasma, in vitro.The results show that such incubation has no effect on either dimethyl HIDA, or diethyl HIDA, but that in the case of para-butyl HIDA, incubation in plasma increases the Rf value to that of HSA (human serum albumin).This indicates that para-butyl HIDA becomes bound to plasma proteins, in contrast to both dimethyl HIDA and diethyl HIDA.     

Magnetic field modulation of receptor binding

Although it is widely held that the magnetic fields encountered during magnetic resonance imaging (MRI) and other procedures have no discernible effect on biological systems, we find that at early times of incubation, the amount of binding of the neurotoxin, alpha-bungarotoxin, to nicotinic acetylcholine receptor is significantly reduced in a constant 2.0-T magnetic field. This finding suggests that steady magnetic fields can directly affect the functional activity of biologically important macromolecules, in this particular case a neurotransmitter receptor.     

Assessment of the binding properties of Granuloszint

¹²³I-Granuloszint (a murine monoclonal antibody — called AK-47 — against NCA-95 glycoprotein of granulocytes) has been proved to be a very convenient and successful radiopharmaceutical for visualizing infectious diseases. For a broad introduction in routine nuclear medicine it was necessary to optimize the labelling method and to determine in vitro exactly those biological and binding parameters which are relevant for an effective application in vivo. Binding to granulocytes has been shown to be specific and saturable (non specific binding about 10%) and is not via the Fc part of the antibody. The investigation of the binding properties of ¹²⁵I-labelled AK-47 gave the following results: affinity constant 5×10⁸ M^-1, 20000–200000 epitopes per granulocyte and an immunoreactivity of more than 90%. Labelling with ¹²³I reduced the immunoreactivity to 40%. The Lindmo method and immunoblotting are used as quality control to check the likely in vivo behaviour of the labelled antibody. There is a good correspondence between the results from the two methods. With our special labelling method and the different in vitro tests we have found a reliable way to control the production and to assure an optimal binding behaviour of ¹²³I-Granuloszint.     

Assessment of the binding properties of Granuloszint

123I-Granuloszint (a murine monoclonal antibody--called AK-47--against NCA-95 glycoprotein of granulocytes) has been proved to be a very convenient and successful radiopharmaceutical for visualizing infectious diseases. For a broad introduction in routine nuclear medicine it was necessary to optimize the labelling method and to determine in vitro exactly those biological and binding parameters which are relevant for an effective application in vivo. Binding to granulocytes has been shown to be specific and saturable (non specific binding about 10%) and is not via the Fc part of the antibody. The investigation of the binding properties of 125I-labelled AK-47 gave the following results: affinity constant 5 x 10(8) M-1, 20,000-200,000 epitopes per granulocyte and an immunoreactivity of more than 90%. Labelling with 123I reduced the immunoreactivity to 40%. The Lindmo method and immunoblotting are used as quality control to check the likely in vivo behaviour of the labelled antibody. There is a good correspondence between the results from the two methods. With our special labelling method and the different in vitro tests we have found a reliable way to control the production and to assure an optimal binding behaviour of 123I-Granuloszint.     

胰岛素-IUdR受体结合特性研究

目的　探讨胰岛素作为受体介导靶向治疗肝癌药物载体的可行性。方法　将碘苷 (I UdR)与胰岛素共价连接 ,采用聚丙烯酰胺凝胶电泳分离纯化 ,高效液相层析鉴定 ,SDS 聚丙烯酰胺凝胶电泳测定相对分子质量。通过受体结合实验 ,分别测定胰岛素、胰岛素 IUdR的IC50 及KI值 ,评价IUdR与胰岛素共价连接后的受体结合特性。结果　胰岛素 IUdR能同12 5I 胰岛素竞争性与肝癌细胞膜结合。胰岛素的IC50 1为 (5 .0 1± 1.2 4)nmol/L ,IC50 2为 (17.75± 4.86 )nmol/L ,KI1值为 (4 .85±1 12 )nmol/L ,KI2为 (17.6 9± 4.81)nmol/L ;胰岛素 IUdR的IC50 1为 (11.5 0± 2 .83)nmol/L ,IC50 2为(19 35± 5 .11)nmol/L ,KI1值为 (11.2 6± 2 .6 5 )nmol/L ,KI2为 (19.30± 5 .0 2 )nmol/L。结论　胰岛素与IUdR共价偶联后 ,仍具有与胰岛素受体结合的生物活性。胰岛素作为受体介导靶向治疗肝癌药物的载体具有广阔的前景