Time-to-tumor dose threshold analysis for intratracheal particle instillation-induced lung tumors in a large carcinogenicity study

Abstract

Background and objectives: A comprehensive time-to-tumor analysis of the 16 dose groups which received intratracheal instillations of “respirable granular bio-durable particles without known significant specific toxicity” (GBP) in a large carcinogenicity study with rats should be conducted.

Methods: The primary lung tumors were mathematically treated as observed in an incidental context (non-fatal occult tumors), based on biological observations and on the fact that lifetime was not considerably reduced even in groups with high tumor frequency. Maximum likelihood estimates of the parameters of time-to-tumor multistage Weibull models were calculated.

Results: Retained dust volume is a highly significantly better dose measure than instilled dust mass, where particle size is taken into account; there is no empirical support for a dose threshold from this study.

Conclusions: Carcinogenicity studies with intratracheal instillation can lead to results that are relevant for the assessment of relative carcinogenic potencies of particles. A dose threshold for GBP is not supported.     

荧光分光光度法检测纳米粒运载的阿霉素在大鼠体内的分布

目的　观察由半乳糖化磁性白蛋白纳米粒运载的阿霉素经舌静脉给药后在大鼠体内的的分布状况。方法　全部大鼠随机分为 4组 ,经舌静脉 ,按分组分别注射 :游离阿霉素组(FADM ) ;磁性阿霉素白蛋白纳米粒 (MADM ) ;半乳糖化磁性阿霉素白蛋白纳米粒组 (Gal2 9 ADM ) ;半乳糖磁性阿霉素白蛋白纳米粒 外加磁场 (Gal2 9 ADM M ) ,剂量均为阿霉素 2 .5mg/kg体重。取全血、心、肺、肝、脾、肾。全血制成血浆 ,器官组织制成匀浆 ,盐酸乙醇法提取阿霉素 ,用荧光光度计测量。结果　静脉注射同等剂量、不同剂型的阿霉素药物后 ,阿霉素在器官中的蓄积程度从高到低 :肝 :D靶肝 >D非靶肝、C >B >A ;心脏、肾、血浆 :A >B >D、C ;脾 :B >A、C、D ;肺 :B>A >C、D。磁性阿霉素白蛋白纳米粒注入体内后 ,在心、肺、肝、脾、肾中的药物浓度在 15～ 3 0min达峰值 ,而半乳糖化后 ,阿霉素的药物峰值提前到 5min或之前。外加磁场和未加磁场的半乳糖化磁性阿霉素白蛋白纳米粒组的药物靶向指数和药物选择指数是均高于磁性白蛋白纳米粒。结论　磁性阿霉素白蛋白纳米粒经半乳糖化后 ,可显著增强阿霉素对肝脏的靶向性 ,并显著降低心、肺、脾、肾、血浆肝外器官的组织阿霉素浓度。利用外加磁场 ,可提高阿霉素在肝脏特定部位蓄积的能力。     

白蛋白阿霉素磁纳米粒在大鼠体内的生物分布

目的：观察白蛋白阿霉素磁纳米粒肝动脉给药与肝动脉给予高剂量的游离药物在体内生物分布上的差异。通过直接测量组织中阿霉素的浓度,进一步证实白蛋白阿霉素磁纳米粒的靶向性。方法：大鼠正中开腹,胃十二指肠动脉插管。实验组：肝动脉注射白蛋白阿霉素磁纳米粒（相当0．5mg/kg阿霉素）左肝外叶应用磁场30min,磁场去除后,动物处死。对照组：肝动脉注射10倍于实验组剂量的阿霉素（5mg/kg),30min后处死。动物处死后,取靶区肝组织、非靶区肝组织、心、肾、脾和肺捣碎、匀浆,用乙醇提取法提取阿霉素,用荧光光度计测量。结果：实验组左肝外叶应用磁场30min,磁区肝组织阿霉素的浓度较非磁区肝组织的阿霉素浓度明显升高,磁共肝组织阿霉素浓度为非磁区肝组织的2．6倍,对照组靶区肝组织和非靶区肝组织的阿霉素浓度无统计学差异,对照组和心和肾组织的阿霉素浓度平均为实验组的9倍以上,脾为4．6倍,肺两组之间无统计学差异。而对照组靶区肝组织的阿霉素只有磁区肝组织阿霉素浓度的1／4。实验组心、肾、肺和脾组织与靶区肝组织阿霉素浓度的比值大大低于对照组。结论：通过纳米粒加磁场的方法从肝动脉给予阿霉素在靶区产生的药物浓度比肝动脉给予10倍剂量的游离阿霉素在靶区产生的药物浓度高3倍。而在心、肾和脾的阿霉素浓度比对照组大为降低。另外,实验组心、肾、肺和脾组织和与靶区肝组织阿霉素的比值比对照组明显降低,其意义若在靶区产生同样的阿霉素的浓度,实验组肝外脏器的阿霉素浓度将大大降低对照组。     

平阳霉素量子点聚乳酸羟基乙酸纳米粒的制备

目的为研究靶向治疗口腔癌颈淋巴结转移灶,制备一种集靶向化疗、定位、实时监测为一体的纳米粒(Nanoparticles,NPs)。方法以平阳霉素(pingyangmycin,PYM)为模型药物,以量子点(quantum dots,QDs)为荧光探针,以聚乳酸羟基乙酸(polylactic-co-glycolic acid,PLGA)为载体,以粒径、荧光性能、载药量和包封率为质量控制指标,通过正交实验设计,用复乳法制备平阳霉素量子点聚乳酸羟基乙酸纳米粒(PYM-QD-PLGA-NPs)。结果经优化制备的PYM-QD-PLGA-NPs包封率为(78.1±2.1)%,载药率为(5.9±0.3)%,平均粒径245.4 nm,电位(-6.68±4.11)mV,具备与QDs相似的荧光性能。结论 PYM-QD-PLGA-NPs具备一定的PYM包载率和QDs荧光性能,符合淋巴靶向的粒径要求,理论上通过口腔癌周注射,可靶向、定位、监测并治疗颈淋巴结转移灶。     

A novel animal model to evaluate the ability of a drug delivery system to promote the passage through the BBB

The purpose of this investigation was to explore the potentiality of a novel animal model to be used for the in vivo evaluation of the ability of a drug delivery system to promote the passage through the blood–brain barrier (BBB) and/or to improve the brain localization of a bioactive compound. A Tween 80^®-coated poly-l-lactid acid nanoparticles was used as a model of colloidal drug delivery system, able to trespass the BBB. Tacrine, administered in LiCl pre-treated rats, induces electrocorticographic seizures and delayed hippocampal damage. The toxic effects of tacrine-loaded poly-l-lactid acid nanoparticles (5 mg/kg), a saline solution of tacrine (5 mg/kg) and an empty colloidal nanoparticle suspension were compared following i.p. administration in LiCl-pre-treated Wistar rats. All the animals treated with tacrine-loaded nanoparticles showed an earlier outcome of CNS adverse symptoms, i.e. epileptic onset, with respect to those animals treated with the free compound (10 min vs. 22 min respectively). In addition, tacrine-loaded nanoparticles administration induced damage of neuronal cells in CA1 field of the hippocampus in all treated animals, while the saline solution of tacrine only in 60% of animals. Empty nanoparticles provided similar results to control (saline-treated) group of animals. In conclusion, the evaluation of time-to-onset of symptoms and the severity of neurodegenerative processes induced by the tacrine–lithium model of epilepsy in the rat, could be used to evaluate preliminarily the capability of a drug delivery system to trespass (or not) the BBB in vivo.     

Design of an inhalable dry powder formulation of DOTAP-modified PLGA nanoparticles loaded with siRNA

Matrix systems based on biocompatible and biodegradable polymers like the United States Food and Drug Administration (FDA)-approved polymer poly(DL-lactide-co-glycolide acid) (PLGA) are promising for the delivery of small interfering RNA (siRNA) due to favorable safety profiles, sustained release properties and improved colloidal stability, as compared to polyplexes. The purpose of this study was to design a dry powder formulation based on cationic lipid-modified PLGA nanoparticles intended for treatment of severe lung diseases by pulmonary delivery of siRNA. The cationic lipid dioleoyltrimethylammoniumpropane (DOTAP) was incorporated into the PLGA matrix to potentiate the gene silencing efficiency. The gene knock-down level in vitro was positively correlated to the weight ratio of DOTAP in the particles, and 73% silencing was achieved in the presence of 10% (v/v) serum at 25% (w/w) DOTAP. Optimal properties were found for nanoparticles modified with 15% (w/w) DOTAP, which reduced the gene expression with 54%. This formulation was spray-dried with mannitol into nanocomposite microparticles of an aerodynamic size appropriate for lung deposition. The spray-drying process did not affect the physicochemical properties of the readily re-dispersible nanoparticles, and most importantly, the in vitro gene silencing activity was preserved during spray-drying. The siRNA content in the powder was similar to the theoretical loading and the siRNA was intact, suggesting that the siRNA is preserved during the spray-drying process. Finally, X-ray powder diffraction analysis demonstrated that mannitol remained in a crystalline state upon spray-drying with PLGA nanoparticles suggesting that the sugar excipient might exert its stabilizing effect by sterical inhibition of the interactions between adjacent nanoparticles. This study demonstrates that spray-drying is an excellent technique for engineering dry powder formulations of siRNA nanoparticles, which might enable the local delivery of biologically active siRNA directly to the lung tissue.     

Acceleration of wound healing by a porous collagen/silk fibroin scaffold carrying zinc oxide nanoparticles北大核心

BACKGROUND: Anti-infective ability determine the success or failure of skin grafting. It is one of the commonly used methods to enhance the anti-infective ability of implants by compounding antibacterial materials with scaffolds. OBJECTIVE:To investigate the effect of porous collagen/silk fibroin scaffolds carrying zinc oxide nanoparticles against infection and inflammation, and to evaluate its effect on wound healing. METHODS: Thirty-two Sprague-Dawley rats with a full-thickness wound on the back skin were randomly divided into two groups. In experimental groiup, porous collagen/silk fibroin scaffolds containing zinc oxide nanoparticles were implanted, while only collagen/silk fibroin scaffolds were implanted in control group. Wound healing was compared between the two groups by measuring residual wound area at 1, 2, 4, 8 weeks post implantation. Hematoxylin-eosin and interleukin 6 immumohistochemical staining were performed at 1, 2, 4 weeks post implantation to observe wound morphology and inflammatory reactions. Meanwhile, expression of interleukin 6 and interleukin 1β was detected by real-time PCR. RESULTS AND CONCLUSION: (1) At 2, 4, 8 weeks post implantation, significantly increased healing rate was observed in the experiment group compared with the control group (P<0.05). (2) Findings from the hematoxylin-eosin staining showed that obvious inflammatory cell infiltration was observed in the control group, but less inflammation with vigorous growth of granulation tissues on the wound surface occurred in the experimental group at 1 week after implantation. Then, the wound repair was basically completed in the experimental group presenting with complete and compact epidermal tissue structure, while scar formation with no skin cover was found in the control group at 4 weeks after implantation. (3) Findings from the interleukin 6 immumohistochemical staining showed that there was interleukin 6 positive expression in both two groups to different extents; at 4 weeks after implantation, the expression of interleukin 6 was remarkably reduced in the control group, but it was still a strong positive expression, while week positive expression of interleukin 6 was observed in the experimental group. (4) Compared with the control group, the mRNA expression of interleukin 6 and interleukin 1β was both lower in the experimental group at 1, 2, 4 weeks after implantation, but there was a significant difference between the two groups at 1 and 2 weeks after implantation (P<0.05). Overall, the porous collagen/silk fibroin scaffold carrying zinc oxide nanoparticles can effectively reduce inflammations following skin injury, and accelerate skin wound healing. © 2018, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.     

地高辛-PLGA抗肿瘤纳米粒子的制备及其抗肿瘤活性的初步研究

目的 制备载地高辛的聚乳酸-羟基乙酸共聚物(PLGA)纳米粒子,提高地高辛的生物利用度,降低其毒副作用.方法 建立测定地高辛-PLGA纳米粒子载药量和包封率的高效液相色谱法;采用乳化溶剂挥发法制备地高辛-PLGA纳米粒子,并通过单因素实验优化制备条件;采用噻唑蓝法评价地高辛和地高辛-PLGA纳米粒子的抗肿瘤能力.结果 以粒径为筛选条件的单因素实验结果表明,制备地高辛-PLGA纳米粒子的最佳条件为PLGA 30 mg,地高辛2 mg,二氯甲烷3 ml,聚乙烯醇质量分数0.5％,超声功率200 W.此制备条件下得到的地高辛-PLGA纳米粒子的粒径约231 nm,包封率为74.61％,载药量为5.37％,且其抗肿瘤活性优于地高辛,差异具有统计学意义(P＜0.05).结论 以PLGA为载体材料制备地高辛-PLGA纳米粒子可增强地高辛的抗肿瘤作用.     

纳米粒子载反义单核细胞趋化蛋白-1基因局部定位转染抑制兔颈动脉内膜损伤后内膜增生的研究

目的 观察纳米粒子包载反义单核细胞趋化蛋白-1（MCP-1）基因局部腔内转染对兔颈动脉球囊损伤后内膜增生的影响。方法 采用球囊导管损伤动脉内膜的方法建立兔颈动脉球囊损伤模型。用纳米粒子包载反义MCP-1基因。采用保留灌注的方法进行局部腔内定位转染。结果 聚合酶联反应检测发现重组基因整合，RNANorthern杂交观察到转基因治疗组有反义MCP-1基因表达，内源性MCP-1基因的表达受抑制，转基因治疗组内膜/中膜面积比降低42%。结论 纳米粒子可以作为转基因载体。反义MCP-1基因的表达能够有效抑制球囊损伤后新生内膜的增生。