重组人血管抑素(rhAGN)包涵体变性与复性初探

在优化的培养条件下，进行rhAGN 5L罐发酵-菌体干重由原摇瓶发酵的3．02g／L增加到8.06g／L，表达量依然稳定在35％；对所产生的包涵体进行溶解变性研究，确定较佳变性缓冲液组成为8mol／L，尿素50mmol／L Tris-HCl，20mmol／LDTT，pH值8．0；凝胶过滤色谱复性效果相对较好，蛋白浓度4．28μg/ml(IC50)时对HEMC细胞的抑制活性达50．1％。     

重组人内皮抑素在大肠杆菌中表达及其生物学活性鉴定

目的　利用大肠杆菌原核表达系统表达重组人内皮抑素Endostatin ,并对其进行生物学活性鉴定。方法　采用RT-PCR方法从人胚肝中钓取人内皮抑素cDNA ,将其克隆入pGEM-TEasy克隆载体中;经全自动序列分析仪测序确证后,将人内皮抑素cDNA亚克隆入原核表达载体pWR450-1 ,构建含人内皮抑素cDNA的重组质粒;将该重组质粒转化入大肠杆菌TG₁中进行诱导表达,表达产物经SDS-PAGE鉴定;表达产物初步纯化复性后以鸡胚尿囊膜血管生成抑制实验和小鼠伤口愈合实验对其进行生物学活性鉴定。结果　成功获得549bp人endostastin基因,测序证实序列正确。经IPTG诱导的重组原核表达质粒表达出重组人内皮抑素的融合蛋白,此蛋白在SDS-PAGE凝胶上显示出一条约75KD的阳性条带。重组人内皮抑素融合蛋白的初纯物在体外能抑制鸡胚尿囊膜血管生成及延长小鼠伤口愈合时间。结论　人内皮抑素融合蛋白在大肠杆菌原核表达系统中高水平表达,并具有抗血管生成活性,为采用抗血管生成方法治疗恶性实体肿瘤的研究奠定了基础     

重组人内皮抑素在大肠杆菌中表达及其生物学活性鉴定

目的 利用大肠杆菌原核表达系统表达重组人内皮抑素Endostatin,并对其进行生物学活性鉴定。方法 采用RT—PCR方法从人胚肝中钓取人内皮抑素cDNA,将其克隆入pGEM—T Easy克隆载体中;经全自动序列分析仪测序确证后,将人内皮抑素cDNA亚克隆入原核表达载体pWR450—1,构建含人内皮抑素cDNA的重组质粒;将该重组质粒转化入大肠杆菌TG1中进行诱导表达,表达产物经SDS-PAGE鉴定;表达产物初步纯化复性后以鸡胚尿囊膜血管生成抑制实验和小鼠伤口愈合实验对其进行生物学活性鉴定。结果 成功获得549bp 人 endostastin基因,测序证实序列正确。经IPTG诱导的重组原核表达质粒表达出重组人内皮抑素的融合蛋白,此蛋白在SDS-PAGE凝胶上显示出一条约75KD的阳性条带。重组人内皮抑素融合蛋白的初纯物在体外能抑制鸡胚尿囊膜血管生成及延长小鼠伤口愈合时间。结论 人内皮抑素融合蛋白在大肠杆菌原核表达系统中高水平表达,并具有抗血管生成活性,为采用抗血管生成方法治疗恶性实体肿瘤的研究奠定了基础。     

重组人内抑素的抗肿瘤活性

目的观察重组人内抑素抗肿瘤活性及对血管内皮细胞增殖的抑制作用。方法用人癌裸鼠移植性肿瘤及小鼠移植性肿瘤模型对重组人内抑素进行抗肿瘤药效学观察,用MTT法观察其对血管内皮细胞及肿瘤细胞增殖的抑制作用。结果重组人内抑素,可明显抑制人胃癌BGC803和人乳腺癌B37裸鼠移植性肿瘤的生长,对小鼠肝癌H22实体瘤亦呈一定的抑制作用。MTT试验结果显示重组人内抑素可抑制人胎脐静脉血管内皮细胞ECV304的增殖,对人结肠癌HCT-8等肿瘤细胞的增殖无影响。结论重组人内抑素具有较强的抗肿瘤作用,其作用机理可能与抑制血管内皮细胞增殖、抑制肿瘤新生血管形成有关。     

重组人内抑素对佐剂性关节炎大鼠滑膜组织血管内皮细胞生长因子表达的影响

目的:观察重组人内抑素对佐剂性关节炎大鼠滑膜组织血管内皮细胞生长因子(vascular endo-thelial cell growth factor,VEGF)的表达及其作用。方法:采用弗氏完全佐剂(Freund’s complete adjuvant,CFA)诱导的佐剂性关节炎(adjuvant-induced arthri-tis,AA)大鼠模型,用足容积法测量关节肿胀度;免疫组织化学法检测血管内皮细胞生长因子的表达及其对微血管密度的影响。结果:弗氏完全佐剂致炎后d 10,佐剂性关节炎大鼠出现继发性炎症,皮下注射给予不同剂量的重组人内抑素(1.25、2.5、5 mg.kg-1),连续7 d,对照组于d 10给予氨甲喋呤(Methotrexate,MTX,1.0 mg.kg-1)。重组人内抑素各剂量组能明显抑制AA大鼠的继发性足肿胀,重组人内抑素各剂量组可不同程度减少AA大鼠关节滑膜组织高表达的VEGF,还可使滑膜组织的微血管密度减少。结论:重组人内抑素可显著抑制AA大鼠滑膜组织VEGF的表达及微血管密度,该作用可能与抑制血管翳的生成及减少滑膜细胞表面VEGF的表达有关。     

人IL-24重组蛋白免疫刺激及血管形成抑制作用

目的 探讨人重组白细胞介素-24(rhIL-24)蛋白体外免疫刺激功能和血管形成抑制作用.方法 将原核稳定表达得到的rhIL-24蛋白刺激外周血单个核细胞(PBMC),ELISA检测其刺激免疫细胞分泌白细胞介素-6(IL-6)、肿瘤坏死因子α(TNF-α)及γ-干扰素(IFN-γ)的活性;利用鸡胚绒毛尿囊膜(CAM)模型观察rhIL-24蛋白抑制血管形成的效应.结果 rhIL-24蛋白孵育的PMBC在不同时段分泌的IL-6、TNF-α及IFN-γ浓度与阴性对照组相比存在显著差异;rhIL-24蛋白能明显抑制CAM二级和三级血管形成,与阴性组比较,差异极显著.结论 rhIL-24蛋白具有明显的免疫刺激功能和血管形成抑制作用.     

鸡胚绒毛尿囊膜在血管生成活性研究中的应用

本文综述了鸡胚绒毛尿囊膜血管生成模型在药物促血管生成和抑制血管生成研究中的应用,对药物载体的选择及药物置入时间的选择等进行了介绍.     

重组人血管内皮抑素的阳离子交换色谱复性与纯化条件研究

对rhEndostatin包涵体蛋白的色谱复性条件进行研究,摸索出最佳的复性、纯化条件,解决其在大肠杆菌中表达提取时遇到的蛋白变性问题。按实验条件对表达的rhEndostatin包涵体蛋白进行提取、洗涤、变性;利用正交法设计重组蛋白的色谱复性、纯化实验;利用SP-Sepharose Fast Flow阳离子交换柱对rhEndostatin包涵体蛋白进行了色谱复性、纯化。最佳复性条件为rhEndostatin上样浓度为2.5 mg/mL,洗脱体积流量为1/20床体积/min(3.5 mL/min),NaCl浓度0.1 mol/L,GSH/GSSG的浓度比为3/0.3 mmol/L。在此条件下纯度约97%,蛋白回收率为90%,重组蛋白的活性最高,IC50达到5μg/mL。     

毛萼乙素抑制人正常及肝癌血管生成的作用研究

目的:研究毛萼乙素对人脐静脉内皮细胞(HUVEC)增殖的影响以及对人肝癌血管生成的影响。方法:采用改良MTT法测试6个浓度的毛萼乙素在体外对原代培养的HUVEC增殖的影响;用人肝癌鸡胚尿囊膜血管复制模型,测定毛萼乙素在器官水平对血管生成的抑制作用。结果:毛萼乙素对HUVEC增殖具有显著的抑制作用,半数抑制浓度(IC50)=7.27μg·mL-1;抑制效应呈剂量和时间依赖性。在剂量为25、50、100μg·mL-1时对人肝癌鸡胚尿囊膜血管面积比的抑制率分别为14.15%、48.72%、60.63%,抑制作用中等;其中剂量在50μg·mL-1时与阳性对照反应停相当(P>0.05)。结论:毛萼乙素对人脐静脉内皮细胞的增殖有显著的抑制作用,并能显著抑制人肝癌细胞诱导的鸡胚尿囊膜血管生成。     

槲皮素抑制血管生成作用的实验研究

目的　研究槲皮素 (Quercetin)对血管生成和培养的人脐静脉内皮细胞 (HUVEC)的影响。方法　采用生长因子 (血管内皮细胞生长因子VEGF、碱性成纤维细胞生长因子bFGF)诱导的鸡胚绒毛尿囊膜 (CAM)血管增生模型观察槲皮素对血管生成的影响 ;利用培养的HUVEC ,用MTT法观察槲皮素抑制内皮细胞增殖的作用 ;流式细胞仪观察槲皮素对HUVEC细胞周期的影响。结果　槲皮素 (0 1、0 0 5和 0 0 2 5mmol·L-1)能明显抑制VEGF诱导的CAM小血管生成 ;槲皮素 (0 1和 0 0 5mmol·L-1)能明显抑制bFGF诱导的CAM小血管生成 ;槲皮素 (2 4 0、12 0 μmol·L-1和 6 0 μmol·L-1)对内皮细胞增殖有抑制作用 ,抑制率分别为 6 7 0 %、5 8 1%和39 7% ;槲皮素 (2 4 0、12 0 μmol·L-1)能显著导致HUVEC的S、G2 期阻滞。结论　槲皮素能抑制VEGF和bFGF诱导的血管生成 ,且对内皮细胞增殖具有抑制作用。     

重组人白细胞介素-18的高浓度复性、纯化和活性检测

目的摸索大规模生产重组人白细胞介素 18(rhIL 18)高效简便、成本低廉的生产工艺。优化rhIL 18高浓度下最优复性、纯化方案 ,建立快速准确的活性检测方法。方法采用液相色谱和光谱学方法检测复性效率 ,筛选确定rhIL 18最优复性条件 ,再用SepheroseFFANX阴离子交换柱结合分子筛HiPrepSephacrylS 10 0进行纯化。采用3 H 掺入法检测rhIL 18产品对人外周血单个核细胞的促增殖作用 ,用流式细胞术检测其促γ 干扰素生成能力。结果建立了一套rhIL 18复性、纯化、活性检测方案。结论液相色谱和光谱学方法相结合 ,可用于检测rhIL 18的复性效率 ,流式细胞术也可用于检测rhIL 18的生物活性。     

重组人血管生长素包涵体复性条件研究

目的摸索重组人血管生长素(rhANG)复性影响条件,以提高rhANG的复性效率。方法超声波破碎菌体,变性萃取rhANG包涵体。分析rhANG包涵体起始浓度、氧化型、还原型谷胱甘肽比例、盐酸胍和添加精氨酸对复性的影响。结果在0.1 mol/L Tris-HCl pH 7~8,还原型、氧化型谷胱甘肽比率为5,盐酸胍为0.2~0.5 mol/L,起始蛋白质浓度0.1~0.2 mg/mL时,rhANG蛋白复性率为60%;0.5 mol/LL-精氨酸有助于复性。结论初步优化rhANG包涵体复性参数,为rhANG的放大制备创造了条件。     

An investigation of the chick chorioallantoic membrane as an alternative model to various biological tissues for permeation studies

Objectives The chick chorioallantoic membrane (CAM) was explored as a biological membrane for use in the study of drug permeation with a Franz diffusion cell. Methods The CAM was removed from fertilized chicken eggs of embryo age 9–18 days. The permeation profiles of nicotine through the fresh CAM were first obtained with a Franz diffusion cell. The permeation profiles of nicotine through frozen CAM, snake skin, pig skin, pig retina and pig buccal mucosa were also determined and compared with those of the fresh CAM. Key findings The permeability coefficient of the CAM varied with its age. The CAM at embryo age 13 was the most robust, showing the lowest standard error in permeability. It was thus chosen for comparative studies with snake skin, pig skin, retina and buccal mucosa. The CAM was found to be most similar to the buccal mucosa in terms of permeation profile and permeability coefficient values. Frozen CAM was also found to have a higher permeability coefficient than fresh CAM. The enhanced permeability was attributed to freezing, which affected the integrity of the CAM structure. Conclusions From the findings, CAM shows potential as an alternative to the pig buccal mucosa as an in‐vitro buccal model. The robustness of the CAM for drug permeation studies is affected by its age.     

Synergic fabrication of succimer coated titanium dioxide nanomaterials delivery for in vitro proliferation and in vivo examination on human aortic endothelial cells

The probable nanotoxicity to human health and the environment is a significant challenge for the sustainable application of nanomaterials in medicine. The cytototoxical effect of succimer (meso-2,3-dimercaptosuccinic acid-DMSA) coated titanium dioxide (DMSA-TiO₂) with cultured human aortic endothelial cells (HAoECs) was assessed in this investigation. Our findings have shown that DMSA-TiO₂ can be accumulated in HAoECs and dispersed in a cytoplasm on the culture medium. DMSA-cytotoxicity TiO₂ effects were dose-responsive, and the concentrations were of little toxicity, and MTT stain testing showed that they had only 0.02 mg ml⁻¹. Meanwhile, the lactate dehydrogenase biomarker was not considerably more remarkable than the biomarker from untreated (control) cells (free DMSA-TiO₂). Though, also without any apparent signs of cell damage, the endocrine functions for prostacyclin I-2 and endothelin-1 and the urea transporter functions were modified. In addition, in vitro endothelial tube development has been shown that HAoECs could induce angiogenesis even with small amounts of DMSA-TiO₂ (0.01 and 0.02 mg ml⁻¹). Further, we have examined the in vivo toxicity and biochemical parameter by animal model. Furthermore, in vivo assessments designated that the resulting DMSA-TiO₂ presented synergistic activities of angiogenesis activity. Overall, these findings show the cytotoxicity of DMSA-TiO₂ and could induce adverse effects on normal endothelial cells.     

姜黄素具有抑制血管生成与诱导肿瘤细胞凋亡双重作用

目的　探讨姜黄素的抗肿瘤机制。方法　采用鸡胚绒毛尿囊膜模型观察姜黄素对血管生成的影响 ;利用培养的肿瘤细胞SMMC 772 1,采用电子显微镜及流式细胞仪观察姜黄素诱导SMMC 772 1细胞凋亡的作用。结果　姜黄素能明显抑制鸡胚绒毛尿囊膜内的血管生成 ,2 0 μmol·L-1的姜黄素即可诱导SMMC 772 1细胞凋亡。结论　姜黄素的抗肿瘤机制是多方面的 ,既可抑制血管生成又可诱导肿瘤细胞凋亡     

The effects of amphotericin B on angiogenesis in chick chorioallantoic membrane

Objective: Amphotericin B (AmB) is widely used as a mainstay in the treatment of sight-threatening fungal endophthalmitis. From the time that itraconazole was discovered to have a previously unknown anti-angiogenic activity, we have suspected that AmB may have possible effects on ocular angiogenesis. The purpose of this study was to evaluate the in vivo anti-angiogenic effect of AmB in the chick chorioallantoic membrane (CAM) model.

Materials and methods: Atak-S type fertilized eggs obtained from the Poultry Institution were used. The eggs were kept under 37?°C at 85–90% relative humidity throughout the experiment. Amphotericin B was prepared in two different concentrations (AmB 125?μg/1?mL and 0.125?μg/1?mL). The CAMs treated with sterile distilled water was specified as controls. About 0.1?mL of each containing 12.5 and 0.0125?µg of AmB, respectively, were dropped to CAM surface. Thirteen eggs were used for each group. The results were evaluated at the 48th hour of the administration of the drugs and recorded by digital camera.

Results: A reduction of angiogenesis in CAM area which treated with 125?μg/1?mL of AmB was appreciable macroscopically. The affected areas showed impaired radial arrangement of small vessels with the presence of avascular zone at periphery. The dose of 0.125?μg/1?mL AmB did not show any visible anti-angiogenic effect. Numerous blood vessels with a radially arranged pattern developed toward the periphery after 48?h of treatment. In the CAMs that treated with distilled water, physiological angiogenesis was observed in allantoic vessels. Vessel formation seems to be similar in CAMs treated with 0.125?μg/1?mL AmB with the presence of visibly non-malformed alive embryos.

Conclusions: The present study gives the impression that AmB has the capacity to serve as an anti-angiogenic treatment. As it is a preliminary CAM study only, further studies on both animals and humans are required.     

Jagged 1在生理性和病理性新生血管形成中的表达变化

目的观察Jagged 1在生理性和病理性新生血管形成中的表达变化,为肿瘤的治疗寻找新的靶点。方法体外培养血管内皮细胞免疫细胞化学法检测其Jagged 1的表达。建立鸡胚尿囊膜动态血管发育模型,免疫荧光化学和Westernblot检测不同发育时期尿囊膜血管中Jagged 1的表达。免疫组织化学和Western blot检测正常结直肠组织和大、中、小三种尺寸的结直肠癌肿块中Jagged 1的表达。结果 (1)免疫细胞化学结果显示,Jagged 1是细胞跨膜蛋白,表达于细胞膜上。(2)成功建立鸡胚尿囊膜动态血管发育模型,其免疫荧光和Western blot结果显示,Jagged 1随着血管的发育而表达,随血管密度、血流量增加而表达上调。(3)免疫组化结果显示Jagged 1在结直肠癌中广泛表达,而在正常皮肤及结直肠组织中表达较少,Jagged 1的表达量同肿瘤的体积有关。结论 Jagged 1在内皮细胞、血管发育初期和肿瘤新生血管中表达上调,表明其可能是新生血管形成的早期事件,参与诱导下游新生血管形成基因的表达。     

重组人超氧化物歧化酶的复性

目的将E .coli以包含体形式表达的重组人超氧化物歧化酶 (rhSOD)恢复天然活性。方法分离包含体 ,用 6mol/L尿素处理 ,透析 ,添加Cu2 + 、Zn2 + ,温浴。结果Cu2 + 、Zn2 + 的加入对于恢复SOD的活性和稳定性是必需的 ,适当提高温度将大大缩短复性时间 ,获得的rhSOD比活可达到 6 0 0 0u/mg以上。结论恢复重组蛋白的天然构型是rhSOD有效结合Cu2 + 、Zn2 + 和完全复性的必要条件     

丹酚酸B对鸡胚绒毛尿囊膜血管新生作用的影响

目的探讨丹酚酸B对鸡胚绒毛尿囊膜血管新生的影响。方法将7日龄鸡胚制备鸡胚绒毛尿囊膜(chick embryo chorioallantoic membrane,CAM)模型,随机分为6个组,分别为PBS(phosphatebuffer solution)对照组,丹酚酸B 4个剂量组(150、50、16.67、5.56 mg.L-1)及VEGF(vascular endo-thelial growth factor)组,培养3 d后时采集数据进行评价。结果丹酚酸B 150、50 mg.L-1组血管新生面积明显高于PBS(phosphate buffer solution)对照组(P<0.01,P<0.05)。结论丹酚酸B可明显促进鸡胚绒毛尿囊膜血管新生。     

sCR1在原核中表达、纯化、复性及活性鉴定

目的采用原核表达载体pET28a在E.coli BL21(DE3)中获得高表达、高活性的重组人sCR1融合蛋白。方法从人外周血中提取总RNA,应用RT-PCR获得人sCR1全长cDNA,将其克隆入原核表达载体pET28a中,构建含人sCR1的重组质粒(pET28a-sCR1),经测序鉴定正确,转化入E.coli BL21(DE3)中,经IPTG诱导,表达产物经SDS-PAGE分析和Western blot鉴定,通过Ni2+-NTA agarose亲和层析纯化后进行复性及生物学活性鉴定。结果获得原核表达载体pET28a-sCR1,经PCR鉴定及测序鉴定,得到重组E.coli BL21(DE3)克隆菌株,经IPTG诱导含有pET28a-sCR1的E.coli BL21(DE3)克隆菌,表达出重组人sCR1融合蛋白。此蛋白在SDS-PAGE上表现为Mr大于29000的蛋白区带,在Western blot分析中可被sCR1的CD35单克隆单抗体(mAb)识别。经Ni2+-NTA agarose亲和层析纯化、复性后得到高纯度的sCR1融合蛋白表达及较高的生物学活性。结论人sCR1融合蛋白在E.coli BL21(DE3)表达系统中的高水平表达,并且有与人体天然蛋白相同的抗原性及其生物学活性。