siRNA作为基因治疗药物的研究难题

RNA干扰（RNAi）现象的发现与研究，为基因治疗带来新的契机，虽然小干扰RNA（siRNA）较单链反义寡核苷酸显示了更好的稳定性与基因沉默效果，但却同样面临基因治疗药物存在的共同问题，如体内的靶向性与有效性、完善的定量分析方法等等。因此，siRNA作为治疗药物还有诸多困难需要克服。目前的研究主要集中在：修饰方式与递送系统研究，以提高siRNA体内的稳定性与靶向性；siRNA定量分析方法学研究，以考察其体内药动学行为并进一步阐明其体内作用机制。     

siRNA新型非病毒载体递送策略新进展

小干扰RNA(siRNA)是一个靶向治疗和精确医学的代表性治疗工具，可通过序列特异性的RNA干扰(RNAi)沉默任何疾病相关基因的表达。然而，它的治疗前景历来受到体内半衰期短、递送困难和安全问题的限制。非病毒载体介导的药物递送已经成为克服这些局限性的一个成功策略，可实现siRNA在体内的有效递送，高效沉默靶基因。目前，已有多种药物处于临床试验中，4种基于siRNA的新型疗法已获得美国FDA的批准，标志着靶向疗法新时代的开始。该文概述了近年来基于siRNA的非病毒载体递送策略的新进展及其应用，并展望了siRNA药物研究的未来发展趋势。     

siRNA药物研究进展

小干扰RNA(small interfering RNA,siRNA)药物作为小核酸药物研发的热点,凭借基因沉默效率高、不良反应可控、合成方便等优点,得到了广泛应用.siRNA裸序列不稳定,在体内递送困难,不易到达靶点发挥作用,成为早期siRNA药物研发的阻力.近年来,siRNA的稳定性修饰以及高效递送系统的开发,大大...     

高分子聚合物用于siRNA递送系统的研究进展

小干扰RNA（siRNA）具有沉默互补的目标信使RNA（mRNA）从而抑制疾病相关基因表达的作用。因其高效性及特异性,siRNA具有作为基因药物的巨大潜力,但其在体内易受到血管屏障、内涵体及RNA酶等因素的影响,从而难以发挥药效。因此,设计高效的能够负载siRNA的纳米载体以使其富集至靶标是目前siRNA药物研发的重要任务,高分子聚合物纳米载体是目前研究热点之一。本文就高分子聚合物纳米载体实现siRNA药物递送的研究进展进行综述。     

载siRNA的纳米制剂研究进展

目的:为小干扰RNA(siRNA)纳米制剂递送的研究提供参考。方法:以"基因治疗""RNA干扰""小干扰RNA""载体系统""siRNA""Gene therapy""RNA interference""Protamine"等为关键词,组合查询1996-2016年在PubMed、中国知网、万方、维普等数据库中的相关文献,对载siRNA的纳米制剂的导入方法、载体类型及影响递送过程的主要因素进行综述。结果:共检索到相关文献500余篇,其中有效文献40篇。载siRNA的纳米制剂导入方法主要分为物理化学法和载体介导法。在载体介导法中的非病毒载体,不仅克服了siRNA半衰期短、生物利用度低等缺点,而且在一定程度上提高了siRNA的递送效率,是现代药剂学研究的一个热点。常用非病毒载体包括阳离子脂质体、二元复合物纳米载体、三元复合物纳米载体。载体靶向性修饰、粒径与表面电荷是递送siRNA纳米载体主要影响因素。siRNA的高效递送依赖于新的高效、低免疫原性载体的开发以及纳米制剂递送系统的优化。因此,可载siRNA的高效、低免疫原性纳米制剂的研究任重而道远。     

shRNA病毒递送载体

RNA干扰(RNA interference,RNAi)是一种有力的基因沉默工具,在功能基因组学、微生物学、基因表达调控机制研究等领域广泛应用。RNAi可以用于鉴定药物靶标及治疗疾病,尤其是传统治疗手段无效的重大疾病。如何将双链小干扰RNA(siRNA)高效传递至体内靶细胞是RNAi成功用于疾病治疗的关键,也是目前研究的热点。由于病毒载体能高效转导多种细胞成为基因工程和基因治疗的主要载体。目前,越来越多的研究将病毒载体应用于介导RNAi,然而病毒载体存在靶向性差、生物安全性等问题。本文针对这些病毒载体的优劣进行归纳并指出今后改进的方向。     

siRNA抗HBV感染领域中的化学修饰和体内传递研究进展

世界人口中约有3.5亿感染乙肝病毒,乙肝病毒感染是急慢性肝炎的主要原因,其与肝纤维化和肝细胞癌的发生密切相关。目前的治疗药物不良反应多或易产生耐药性,因此迫切需要找到新的治疗手段。本文依据近5年来国内外文献进行分析、归纳、总结,综述了治疗HBV感染的小干扰RNA（small RNA interference,siRNA）药物在化学修饰和体内传递方面新进展。RNAi途径可实现病毒基因转录后沉默,特异性和有效性地抑制HBV基因的表达和复制,是治疗HBV感染的一种新颖而有效的途径。而小干扰RNA（siRNA）的化学修饰和体内传递研究,可提高其在体内的稳定性和靶向性。     

小分子干扰RNA非病毒纳米载体的设计进展

小分子干扰RNA(small interfering RNA,siRNA)进入临床应用最关键的环节是如何有效通过药物递送系统将siRNA递送到特异性靶细胞或靶组织。非病毒纳米载体递送系统具有低的免疫原性、良好的靶向性和生物相容性,是近年来国内外药剂工作者研究的热点。其相应的研究也必将大大增加siRNA有效递送,使其有进一步成为治疗药物的可能性。本文根据国内外的文献报道,将siRNA非病毒纳米载体的设计进展进行了综述。     

RNA干扰与药物的研究进展

RNA干扰是由双链RNA诱导的序列特异性的基因沉默，目前被广泛用于药物研究，特别是针对肿瘤、病毒感染性疾病、血液病及神经退行性疾病等的治疗药物。随着核酸药物在体内靶向转运技术的不断发展，RNA干扰有可能成为一种新型的治疗途径。     

不对称RNA干扰研究进展

RNA干扰是生物医学研究,特别是基因功能研究中的重要工具.目前在哺乳细胞和临床研究中的RNA干扰技术主要由相同长度对称的双链小干扰RNA(siRNA)介导.正义链和反义链长度不一致的不对称双链小干扰RNA(aiRNA)能更有效地使相应的靶基因沉默,并且降低脱靶效应,提高体内外稳定性,成为疾病治疗的新希望.本文就aiRNA的研究进展作一综述.     

大鼠溃疡性结肠炎模型的实验研究

目的对不同剂量的三硝基苯磺酸（ＴＮＢＳ）引起的大鼠溃疡性结肠炎（ＵＣ）模型进行观察和评价。方法采用一次性直肠注入大鼠ＴＮＢＳ（２５～１５０ｍｇ·ｋｇ－１）的３０％乙醇溶液，引起慢性炎症性肠疾病（ＩＢＤ），３ｗｋ后外死动物对各剂量下动物结肠的重量、髓过氧化物酶（ＭＰＯ）活性及组织形态学变化进行观察和评价。结果ＴＮＢＳ在１００～１５０ｍｇ·ｋｇ－１剂量下引起的ＵＣ肠壁明显增厚，炎症和溃疡至少维持７ｗｋ时间，ＭＰＯ活性值显著性升高，组织学检查发现粘膜及粘膜下层有大量中性粒细胞及淋巴细胞、巨噬细胞、纤维细胞浸润，肉芽组织及隐窝脓肿形成，５０ｍｇ·ｋｇ－１剂量时有一较轻度的损伤。２５ｍｇ·ｋｇ－１时对结肠的重量、ＭＰＯ活性及损伤指数都没有显著性改变（Ｐ＞０．０５）。结论用ＴＮＢＳ引起大鼠实验性ＵＣ，其溃疡和炎症维持一较长时间，这一病理特征为炎症性疾病防治药物的研究提供了条件；本模型的最佳剂量为１００ｍｇ·ｋｇ－１左右     

脑脊液转铁蛋白及免疫球蛋白含量变化在小儿中枢神经系统感染时的临床意义

目的　通过对小儿中枢神经系统感染时Tf、Ig在脑脊液中含量的变化及其相关性分析 ,为鉴别诊断及更切实的判定病情和估计预后提供参考依据。方法　应用速率散射比浊法测定脑脊液中Tf、Ig。结果　 (1 )三组急性期脑脊液中Tf、Ig含量均高于恢复期。 (2 )结脑组Tf、IgG增高明显 ,化脑组IgM增高明显。病脑组变化最小。 (3)恢复期脑脊液中Tf、Ig含量与对照组比较 ,结脑中Tf、IgG、IgM高于对照组 ,化脑和病脑组IgM均高于对照组 ,Tf、IgG均无差异 ,各组IgA与对照组相比无显著性差异。 (4)病脑急性期Tf与IgG呈正相关 ,恢复期与IgA呈正相关 ;化脑组急性期Tf与IgM、IgG呈正相关 ,恢复期与IgM呈正相关 ;结脑急性期Tf与IgA、IgM均呈正相关 ,恢复期与IgG呈正相关。结论　 (1 )Tf与IgG是诊断结脑的良好指标 ,IgM是诊断化脑的良好指标 ,当脑脊液中IgM >30mg L时 ,可基本除外病脑 ,当脑脊液中IgM <60mg L时 ,化脑的可能性较小。 (2 )Tf与Ig一样 ,可作为判断中枢神经系统感染时血脑屏障及脑损伤与恢复程度的重要指标     

HPLC法测定丝裂霉素C聚氰基丙烯酸正丁酯纳米粒中丝裂霉素C的含量

目的:建立高效液相色谱法测定丝裂霉素 C 聚氰基丙烯酸正丁酯纳米粒(MMC-PBCA-NP)中药物含量。方法:采用C_(18)柱(4.6 mm×150 mm,5 μm),以混合磷酸盐缓冲液-乙腈(85:15)为流动相,流速为1 mL·min~(-1),紫外检测器,检测波长为365 nm。结果:丝裂霉素 C(MMC)浓度在5～250 μg·mL~(-1)范围内与峰面积呈良好的线性关系,r=0.9998;平均回收率(n=6)为98.15%。结论:本法专属性强,操作简便,结果准确。适用于 MMC-PBCA-NP 的质量控制。     

Effects of Nitro-L-Arginine on Blood Pressure and Cardiac Index in Anesthetized Rats: A Pharmacokinetic-Pharmacodynamic Analysis

Purpose. Nitric oxide synthase (NOS) inhibitors such as Nitro-L-arginine (L-NA) are being considered for the management of hypotension observed in septic shock. However, little information is available regarding the pharmacokinetic and pharmacodynamic properties of these agents. Our objective was to examine the relationships between L-NA plasma concentration and various hemodynamic effects such as cardiac index (CI), mean arterial pressure (MAP), and heart rate (HR) elicited by L-NA administration in rats. Methods. L-NA was infused at doses between 2.5 – 20 mg/kg/hr in anesthetized rats over one hour. Hemodynamic effects and plasma L-NA levels were determined. Results. Infusion of L-NA resulted in dose-dependent increases in MAP and systemic vascular resistance (SVR), decreases in CI, and minimal change in HR. The relationships between the hemodynamic effects and plasma L-NA levels were not monotonic, and hysteresis was observed. Using nonparametric analysis, the equilibration half-time (t_1/2,keo) between plasma L-NA and the hypothetical effect site was determined to be 51.5 ± 6.6 min, 42.4 ± 10.1 min, 43.4 ± 9.0 min for MAP, CI, and SVR, respectively (n = 14). The E_max and EC₅₀ values obtained were + 32.5 ± 8.4 and 2.6 ± 1.3 g/ml for MAP and –52.9 ± 15.6 and 3.7 ± 1.8 g/ml for CI, respectively. Conclusions. Although L-NA can bring about beneficial elevation of MAP, such effect is always accompanied by a stronger effect on CI depression. Dose escalation of L-NA may bring about detrimental negative inotropic effect and loss of therapeutic efficacy.     

Krill-Derived Phosphatidylserine Improves TMT-Induced Memory Impairment in the Rat

The present study examined the effects of krill-derived phosphatidylserine (Krill-PS) on the learning and memory function and the neural activity in rats with trimethyltin (TMT)-induced memory deficits. The rats were administered vehicle (medium-chain triglyceride: MCT) or Krill-PS (50, 100 mg/kg, p.o.) daily for 21 days. The cognitive improving efficacy of Krill-PS in TMT-induced amnesic rats was investigated by assessing the Morris water maze test and by performing choline acetyltransferase (ChAT), acetylcholinesterase (AChE) and cAMP responsive element binding protein (CREB) immunohistochemistry. The rats with TMT injection showed impaired learning and memory of the tasks and treatment with Krill-PS produced a significant improvement of the escape latency to find the platform in the Morris water maze at the 2^nd and 4^th day compared to that of the MCT group (p<0.05). In the retention test, the Krill-PS+MCT groups showed increased time spent around the platform compared to that of the MCT group. Consistent with the behavioral data, Krill-PS 50+MCT group significantly alleviated the loss of acetylcholinergic neurons in the hippocampus and medial septum compared to that of the MCT group. Treatment with Krill-PS significantly increased the CREB positive neurons in the hippocampal CA1 area as compared to that of the MCT group. These results suggest that Krill-PS may be useful for improving the cognitive function via regulation of cholinergic marker enzyme activity and neural activity.     

Physical State of Misoprostol in Hydroxypropyl Methylcellulose Films

Scanning electron (SEM) and light microscopy (LM), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) techniques were utilized to determine the miscibility of misoprostol and HPMC in the films with a misoprostol content from 0 to 29%, prepared using ethanol and methylene chloride/methanol (MeCl₂/methanol, 50:50). Transmission infrared (TIR) analysis was used to look for evidence of any interaction between misoprostol and HPMC. The LM and SEM analysis of the ethanol cast films indicated no oil droplets. The DSC thermograms of the films showed no evidence of a –33°C transition, which is characteristic of pure misoprostol. The DMA showed that the glass–rubber transition temperature (T _g) of the pure HPMC was lowered from 163 to 125–130 and 85–87°C in the presence of 10 and 27–28% misoprostol. Based on these results it is suggested that misoprostol is solubilized in HPMC at concentrations up to 29%. The TIR analysis of the films showed no evidence of interaction between misoprostol and HPMC.     

防治痴呆新药的构效关系研究

阿尔茨海默病、帕金森病和血管性痴呆是严重危害老年人生命健康的多发病。目前临床应用的防治痴呆药物的作用机制主要涉及改善胆碱能神经递质、激动多巴胺(DA)受体、阻滞N-甲基-D门冬氨酸(NMDA)受体和改善脑血管功能等。综述了近年来报道的防治痴呆新药的构效关系研究进展。     

Intermittent versus continuous neuroleptic treatment in a rat model

The treatment schedule for neuroleptic therapy is of relevance when evaluating the development of side-effects. Seventy-five rats were treated discontinuously or continuously with the predominantly dopamine D₂ receptor blocker haloperidol or the combined dopamine D₁/D₂ receptor blocker zuclopenthixol for 15 weeks. During and after treatment, a broad spectrum of behavioural parameters including vacuous chewing movements and tongue protrusions were observed. Discontinuous neuroteptic treatment as opposed to continuous neuroleptic treatment produced a significant long-lasting increase in oral activity. The changes were most pronounced in haloperidol-treated rats. The differences observed may have methodological implications for animal models of neuroleptic-induced movement disorders. Our finding are consistent with the hypothesis that pharmacological sensitization to the dyskinetic side-effects of neuroleptics develops when the drug effect is allowed to wear off between repeated administration.     

HPLC-RI法测定银杏叶提取物中4种内酯的含量

目的:建立高效液相色谱法测定银杏叶提取物中4种内酯(银杏内酯 A、银杏内酯 B、银杏内酯 C、白果内酯)的含量。方法:采用 Symmetryshield 型 C_(18)色谱柱(3.9 mm×150 mm,5 μm),以甲醇-水(30:70)为流动相,流速为1.0 mL·min~~(-1),用外标法测定,示差折光检测器检测。结果:4种内酯浓度在0.02～0.24 mg·mL~(-1)范围内,与色谱峰面积呈良好线性关系,相关系数在0.9984～0.9998之间,检测限在0.025～0.035 μg之间,回收率在99.0%～100.2%之间。结论:本方法简单、准确、可靠、灵敏,适用于实验室和企业常规质量控制。