SA脂质体介导GFP／bFGF基因在豚鼠耳蜗中的表达

目的 :观察天然碱性脂 (Stearylamine,SA)脂质体介导绿色荧光蛋白 /碱性成纤维细胞生长因子(GFP/bFGF)基因于不同时间段豚鼠耳蜗中的表达 ,为进一步研究耳聋的基因治疗提供实验基础。方法 :取豚鼠 1 6只 ,分成 4组 ,每组 4只。其中 3只右耳圆窗内注入SA -GFP/bFGF复合物 ,1只同法注入生理盐水作为对照。分别于术后第 2、7、1 4、2 1天取材。在荧光显微镜下观察GFP的表达 ,用免疫组化法检测bFGF的转导情况。结果 :荧光显微镜下见双侧耳蜗于术后第 2天开始部分细胞发出绿色荧光 ,第 7天达到高峰 ,支持细胞及内外毛细胞均显荧光 ,细胞轮廓清晰 ;第 1 4天开始减弱 ,第 2 1天消失。免疫组化染色显示 ,除血管纹外 ,耳蜗各回Corti器、螺旋韧带、螺旋缘及螺旋神经节细胞均有高浓度的表达产物 ,对照动物呈阴性表达。结论 :SA脂质体介导的GFP/bFGF基因单耳给药双侧耳蜗均有高效表达 ,为进一步研究基因治疗耳聋提供了可能。     

Suppression of experimental allergic encephalomyelitis by the encephalitogenic peptide, in solution or bound to liposomes

We have investigated the ability of liposome-bound encephalitogenic peptide to suppress experimental allergic encephalomyelitis (EAE) in the guinea pig. EAE was induced by challenge with the encephalitogenic peptide, residues 113-122 of human myelin basic protein (MBP) in complete Freund's adjuvant. The peptide was acylated with stearic acid in order to anchor it to the lipid bilayer. The liposomal-bound peptide effectively suppressed clinical signs of EAE at relatively low doses, when given subcutaneously or intraperitoneally without incomplete Freund's adjuvant, several days after challenge. In vitro proliferation of lymphocytes from treated, protected animals in response to the peptide was greatly decreased but that to the purified protein derivative of tuberculin antigen was not, indicating an antigen-specific effect. However, histological signs of EAE were not reduced. The free peptide in solution was somewhat less effective when given intraperitoneally but was as or nearly as effective as liposome-bound peptide when given subcutaneously. Binding to liposomes may decrease the rate of clearance or degradation of the peptide when given intraperitoneally.     

Comparison of anticonvulsant effects of valproic acid entrapped in positively and negatively charged liposomes in amygdaloid-kindled rats

Intraperitoneal injection of free valproic acid (VPA) suppressed amygdaloid-kindled seizure 1 h after injection in rats, but had no effect at 24 h. VPA entrapped in positively charged liposomes showed a prolonged anticonvulsant effect lasting for 2 days, while the effect evaluated at 1 h was not different from that with free VPA. VPA entrapped in negatively charged liposomes exerted a significantly stronger effect at 1 h than did free VPA, while it had no significant effect at 24 h. These results suggest that surface charges on liposomes play an important role in modifying the anticonvulsant effect of VPA.     

The effect of surface sugars on liposomes in immunopotentiation

The effect of surface sugars of liposomes on the immunological responses to entrapped antigen has been investigated. alpha-Mannose and beta-galactose were grafted on the surface of liposomes containing lysozyme by covalent coupling of p-aminophenyl-D-glycosides to phosphatidyl ethanolamine liposomes using glutaraldehyde. Subcutaneous administration of antigen entrapped in beta-galactose liposomes stimulated an antibody response comparable to that elicited by sugar-free neutral liposomes. However, alpha-mannose bearing liposomes with entrapped lysozyme elicited an immune response similar to that induced by lysozyme in saline. Based on these observations it is suggested that alpha-mannose liposomes, that are specifically recognized by macrophages, are taken up rapidly by receptor mediated endocytosis and that the entrapped antigen is then rapidly degraded, resulting in low antibody production.     

脂质体介导Neo R和Lac Z双标志基因共转导原代造血细胞及其表达的研究(英文)

在介导体内外基因转移方面,脂质体已显示出许多优于病毒载体的特征.然而,有关脂质体介导造血细胞基因转移的报道很少.本文描述了脂质体介导双标志基因(Neo~R和Lac Z)在体外共转移进入人及小鼠原代造血细胞的研究.基因转移的效率通过X-gal染色及观察集落的形成来评价.结果显示,在存在G418的体系中,转导细胞能够存活并形成集落,而未转导细胞则不能存活.同时,转导阳性细胞能够被X-gal染成蓝色.其蓝染阳性细胞率在人及小鼠造血细胞于G418选择前分别为13.33± 2.68%和16.28± 2.95%.经G418选择启分别达到46.06±3.47%及43.45±4.1%,显著高于筛选前(P<0.01).提示,利用脂质体这一简单、安全的转导策略在原代造血细胞可获得高效的基因转移及稳定的表达.同时,共转导双标志基因进入造血细胞可用作高集转导阳性细胞.这一结论对于临床进一步探讨造血重建的生物学特征、追踪白血病的复发机制以及利用造血细胞作为靶细胞进行基因治疗的研究提供了实验依据.     

丁胺卡那霉素地塞米松复方脂质体在兔眼玻璃体内的药代动力学研究

目的 应用丁胺卡那霉素地塞米松(丁卡地塞)复方脂质体玻璃体内注射以延长两种药物的半衰期.方法 大白兔随机分4组,正常眼2组和眼内炎眼2组均分别注射复方脂质体和游离药物.结果 丁卡在正常眼复方脂质体的半衰期较游离药物延长1.8倍,在眼内炎眼延长3.4倍.地塞在正常眼复方脂质体半衰期较游离药物延长22.5倍,在眼内炎眼延长46.2倍.结论 丁卡地塞复方脂质体玻璃体内注射使丁卡和地塞两种药物的半衰期有明显延长.     

经尿道灌注自杀基因治疗大鼠膀胱癌的实验研究

目的:探讨经尿道膀胱灌注脂质体和逆转录病毒载体介导的自杀基因(HSVtk),观察在羟基无环鸟苷(ganciclovir,GCV)作用下大鼠膀胱肿瘤的生长情况.方法:用N-甲基-亚硝基脲(MNU)膀胱灌注建立大鼠原位膀胱癌模型.经尿道膀胱灌注脂质体、逆转录病毒载体HSVtk基因,随后腹腔内注射GCV,连续6天.结果:经尿道膀胱灌注HSVtk基因后48h,RT-PCR检测出膀胱肿瘤中HSVtk基因表达.逆转录病毒组和脂质体组膀胱总重量与裸质粒组和对照组相比有显著差异,表明膀胱肿瘤的生长被抑制.TUNEL法原位检测肿瘤组织中凋亡细胞不仅出现在表层细胞,而且深层细胞大量凋亡,推测旁观者效应可能发挥了一定作用.结论:经尿道膀胱灌注脂质体DNA或重组逆转录病毒载体可以向肿瘤转导HSVtk基因.HSVtk/GCV系统能抑制大鼠原位膀胱肿瘤的生长,显示出抗肿瘤作用.     

白细胞介素—2脂质体的制备及其抗肿瘤作用

研究白细胞介素－２脂质体对小鼠Ｂ－１６轩色素瘤肺转移瘤的抑瘤活性和对荷瘤鼠脾淋巴细胞增殖的影响。方法：改良薄膜－超声法制备ＩＬ－２脂质体；正常及免疫受抑的Ｂ－１６黑色素瘤肺转移Ｃ５７ＢＬ／６Ｎ小鼠ｉｐ游离或脂质体包封的ＩＬ－２，检测肺湿重，肺转移结节数和脾淋巴细胞６３Ｈ－ＴｄＲ掺入量。结果：制备的ＩＬ－２脂质体为直径２００－２５００ｎｍ５ 大单层脂