Fabrication and Evaluation of Porous Keratin/chitosan (KCS) Scaffolds for Effectively Accelerating Wound Healing*

ObjectiveTo develop a dressing with desired antibacterial activity, good water maintaining ability and mechanical properties for wound healing and skin regeneration. MethodsThe chitosan with different concentrations were added in keratin solution to form porous keratin/chitosan (KCS) scaffolds. The morphological characteristics, chemical composition, wettability, porosity, swelling ratio and degradation of the scaffolds were evaluated. The antibacterial activity was tested by usingS. aureusandE. colisuspension for 2 h. And L929 fibroblast cells culture was used to evaluate the cytotoxicity of the KCS scaffolds. ResultsThe adding of chitosan could increase the hydrophobicity, decrease porosity, swelling ratio and degradation rate of the KCS porous scaffolds.Mechanical properties of KCS scaffolds could be enhanced and well adjusted by chitosan. KCS scaffolds could obviously decrease bacteria number.The proliferation of fibroblast cells in porous KCS patch increased firstly and then decreased with the increase of chitosan concentration. It was appropriate to add 400 μg/mL chitosan to form porous KCS scaffold for achieving best cell attachment and proliferation compared with other samples. ConclusionThe porous KCS scaffold may be used as implanted scaffold materials forpromoting wound healing and skinregeneration.     

壳聚糖活性炭栓预防宫颈术后并发症的临床价值

目的探讨壳聚糖活性炭栓对宫颈术后并发症的预防作用及其治疗宫颈病变的临床价值.方法选取宫颈病变行LEEP治疗或微波治疗的患者进行研究.行LEEP治疗480例,随机分为治疗组(240例)和对照组(240例),治疗组LEEP术后即开始给予壳聚糖活性炭栓阴道上药,共7 d,对照组不进行阴道上药,术后碘伏纱布阴道填塞24 h.微波治疗480例,随机分为治疗组(240例)和对照组(240例),治疗组微波治疗术后立即给予壳聚糖活性炭栓阴道上药,共7 d,对照组不进行阴道上药.结果无论是微波治疗还是LEEP治疗,治疗组在术后阴道流液时间、阴道流血量及持续时间方面均明显少于对照组,创面愈合情况优于对照组,创面愈合时间较对照组明显缩短(P<0.05).结论壳聚糖活性炭栓可以明显减少宫颈病变患者术后并发症的发生,缩短创面愈合时间,增加患者术后舒适度,具有显著的临床意义,值得临床推广.     

高温高压对壳聚糖／甘油磷酸钠温敏凝胶释药性能的影响

目的：研究高温高压后的壳聚糖／甘油磷酸钠凝胶温敏、释药性能。方法：观察不同比例的壳聚糖和甘油磷酸钠混合液的凝胶时间、pH值变化。粘度测试比较不同比例壳聚糖／甘油磷酸钠混合液粘度变化。在37℃形成凝胶后,观察该体系作为奥硝唑药物模型载体的释药性能。结果：随着壳聚糖／甘油磷酸钠混合液中甘油磷酸钠的比例增加,溶液pH值增加,在37℃下,壳聚糖／甘油磷酸钠凝胶时间缩短,但当壳聚糖／甘油磷酸比例为2：1、1：1时,溶液不凝胶。粘度实验表明,4种比例（9：1、8：1、7：1、6：1）壳聚糖／甘油磷酸溶液随着时间增加,粘度明显增加,到10 min后粘度基本不变化,9：1比例组粘度最大为（53±0．9）Pa·s。药物释放实验表明,以奥硝唑为释药模型,该凝胶可持续释放200 min以上。结论：改进消毒方法后的壳聚糖／甘油磷酸钠,增加甘油磷酸钠比例可以提高溶液pH值,可在37℃下快速形成凝胶。该凝胶具有温敏性,具有缓慢释放药物能力。     

辛伐他汀凝胶盖髓剂初步研究Ⅰ

目的:制备辛伐他汀温敏性凝胶缓释系统,初步探索辛伐他汀促进牙髓修复的作用。方法:制备辛伐他汀壳聚糖温敏性缓释凝胶,紫外分光光度法检测缓释效果并绘制释放曲线。大鼠磨牙行活髓切断术,分别以载有辛伐他汀的壳聚糖缓释凝胶(简称辛伐他汀缓释凝胶)、壳聚糖/甘油磷酸钠凝胶(简称空白凝胶)、氢氧化钙盖髓,并设对侧为空白对照组,术后1、3、7、14、28 d处死,拍摄X线片,HE染色观察牙髓情况。结果:37℃下,空白凝胶15 min内凝固,辛伐他汀缓释凝胶8 min内凝固。48 h辛伐他汀快速释放,60 d后达到溶质梯度平衡,凝胶内的辛伐他汀持续平稳释放,累计释放率为61.5%。活髓切断术后,氢氧化钙组28 d受试牙根管口见高密度钙化屏障,辛伐他汀缓释凝胶组术后7、14、28 d的根管口见高密度钙化屏障,空白凝胶组未见高密度影像。HE染色结果显示,辛伐他汀组术后7 d盖髓断面牙髓结构正常,成牙本质样细胞向断面聚集并形成早期钙化团块,28 d形成早期钙化桥;氢氧化钙组术后7 d表现为盖髓剂下方断面和髓腔内牙髓组织凝固性坏死现象,失去正常结构,与周围组织界限明显。结论:辛伐他汀缓释凝胶缓释性能良好。作为盖髓剂,其组织相容性好,有促进修复性牙本质形成的潜能。     

Protective effect of chitosan treatment against acetaminophen-induced hepatotoxicity

Acetaminophen (APAP) is the most commonly reported toxic ingestion in the world. Severe liver injury resulting from overdose or chronic use of APAP remains a significant clinical problem. In recent years, the mechanisms underlying liver injury caused by APAP have become much better understood. We have studied the protective effect of chitosan supplementation against APAP-induced hepatotoxicity with respect to changes in the levels of total and lipid-bound sialic acid in the serum and in the liver tissue and changes in the activity of diagnostic marker enzymes, lipid peroxidation, and ceruloplasmin oxidase enzyme in normal and experimental groups of rats. During the experimental period, chitosan (200 mg/kg body weight per day) was administered to APAP + chitosan-treated rats by oral gavage. Results showed that treatment with APAP induced a significant increase in the serum alanine aminotransferase and alkaline phosphatase activities, in total and lipid-bound sialic acids levels, and in the liver lipid peroxide content. The administration of chitosan significantly prevented APAP-induced alterations in the levels of diagnostic marker enzymes, total sialic acid, lipid-bound sialic acid, and malondialdehyde in the experimental groups of rats. Furthermore, chitosan administration increased the activity of ceruloplasmin oxidase. In conclusion, our results suggest that chitosan has a protective effect on APAP-induced hepatic injury in rats. The study sheds light on the therapeutic potential of chitosan in an APAP-induced hepatotoxicity model.     

小鼠神经缺损管式修复后长时程功能恢复与再生评价

目的了解壳聚糖/聚乳酸-乙醇酸共聚体(PLGA)人工神经移植物修复小鼠神经缺损后神经功能长时程恢复水平与再生神经成熟度。方法采用人工神经移植物桥接修复小鼠坐骨神经缺损(n=6),以自体神经修复(n=6)和缺损组(n=6)为对照,术后1年采用热痛阈测定、电生理学、激光多普勒血流检测评定神经功能,采用靶肌湿重比、组织学和电子显微镜等技术综合评定神经重支配和再生神经成熟度。结果人工神经移植物组足底痛觉反应潜伏期、神经源性血管扩张程度、腓肠肌复合肌动作电位(CMAPs)波幅和潜伏期、靶肌湿重比、再生轴突数量等指标与自体神经修复组相近,但与健侧相比CMAPs潜伏期较长,髓鞘较薄,轴突直径分布滞后。结论人工神经移植物修复小鼠神经缺损术后1年感觉及自主神经功能、再生神经数量和靶肌重支配水平与自体神经修复相当,但再生神经纤维成熟度未达正常。     

载乳铁蛋白壳聚糖微球/nHA/Co复合材料的制备

目的:制备载乳铁蛋白壳聚糖微球/nHA/Co复合材料作为组织工程材料拟修复骨缺损。方法:通过乳化交联法法制备载乳铁蛋白壳聚糖微球,化学沉淀法制备纳米羟基磷灰石,改良酸酶法提取Ⅰ型胶原,应用京尼平交联制备复合材料,SEM检测材料的微观结构,测定壳聚糖微球对乳铁蛋白的载药率和包封率。结果:复合材料及各组成成份扫描电镜观察均具有较好的微观形态,壳聚糖微球对乳铁蛋白的载药率为(1.06±0.06)%,包封率为(88.2±2.9)%。结论:载乳铁蛋白壳聚糖微球/nHA/Co复合材料具有较好的微观形态。     

Carboxymethylation of ulvan and chitosan and their use as polymeric components of bone cements

Ulvan, extracted from the green algae Ulva lactuca, and chitosan, extracted from Loligo forbesis squid-pen, were carboxymethylated, yielding polysaccharides with an average degree of substitution of ～98% (carboxymethyl ulvan, CMU) and ～87% (carboxymethyl chitosan, N,O-CMC). The carboxymethylation was confirmed by Fourier transform infrared spectroscopy and quantified by conductimetric titration and ¹H nuclear magnetic resonance. The average molecular weight increased with the carboxymethylation (chitosan, M_n 145→296 kDa and M_w 227→416 kDa; ulvan, M_n 139→261 kDa and M_w 368→640 kDa), indicating successful chemical modifications. Mixtures of the modified polysaccharides were tested in the formulation of polyacrylic acid-free glass-ionomer bone cements. Mechanical and in vitro bioactivity tests indicate that the inclusion of CMU in the cement formulation, i.e. 0.50:0.50 N,O-CMC:CMU, enhances its mechanical performance (compressive strength 52.4 ± 8.0 MPa and modulus 2.3 ± 0.3 GPa), generates non-cytotoxic cements and induces the diffusion of Ca and/or P-based moieties from the surface to the bulk of the cements.     

Single-step electrochemical deposition of antimicrobial orthopaedic coatings based on a bioactive glass/chitosan/nano-silver composite system

Composite orthopaedic coatings with antibacterial capability containing chitosan, Bioglass® particles (9.8 μm) and silver nanoparticles (Ag-np) were fabricated using a single-step electrophoretic deposition (EPD) technique, and their structural and preliminary in vitro bactericidal and cellular properties were investigated. Stainless steel 316 was used as a standard metallic orthopaedic substrate. The coatings were compared with EPD coatings of chitosan and chitosan/Bioglass®. The ability of chitosan as both a complexing and stabilizing agent was utilized to form uniformly deposited Ag-np. Due to the presence of Bioglass® particles, the coatings were bioactive in terms of forming carbonated hydroxyapatite in simulated body fluid (SBF). Less than 7 wt.% of the incorporated silver was released over the course of 28 days in SBF and the possibility of manipulating the release rate by varying the deposition order of coating layers was shown. The low released concentration of Ag ions (<2.5 ppm) was efficiently antibacterial against Staphyloccocus aureus up to 10 days. Although chitosan and chitosan/Bioglass® coating supported proliferation of MG-63 osteoblast-like cells up to 7 days of culture, chitosan/Bioglass®/Ag-np coatings containing 342 μg of Ag-np showed cytotoxic effects. This was attributed to the relatively high concentration of Ag-np incorporated in the coatings.     

茶碱壳聚糖缓释微球吸入对小鼠支气管哮喘模型气道炎症及气道痉挛的影响

目的 探讨茶碱缓释微球吸入对支气管哮喘(简称哮喘)小鼠肺泡灌洗液、细胞因子及肺组织病理改变的影响.方法 40只6～8周龄健康雄性BALB/C小鼠随机分为阴性对照组、模型组、布地奈德组、茶碱壳聚糖缓释微球吸入组,每组10只,同步饲养2周.小鼠于第1天、第8天及第15天OVA致敏,最后一次致敏后连续7d吸入1％的OVA激发,以建立哮喘模型.激发前各组给予所对应药物治疗,取肺泡灌洗液后,分别测定其中总蛋白、白细胞总数及分类,酶联免疫吸附试验测定BALE中IL-4、TNF-α.同时对肺组织切片进行HE染色,形态学检查和炎症状况的病理评分,采用计算机图像软件测定支气管壁面积(WAt)、管腔内径(T)并应用内周长(Pi)标准化.结果 模型组中的白细胞总数、嗜酸粒细胞、总蛋白、IL-4、TNF-α均明显高于阴性对照组.吸入布地奈德、茶碱壳聚糖微球组的上述指标较哮喘模型组明显降低(P＜0.05),两组之间差异无统计学意义;茶碱壳聚糖组中的巨噬细胞明显高于其余各组(P＜0.01).吸入布地奈德组和茶碱壳聚糖组小鼠肺组织切片病理形态显示,气道周围炎症较单纯哮喘模型组明显改善,两组患者炎症病理评分较单纯哮喘模型组亦明显改善,且两组之间差异无统汁学意义.各实验组支气管壁面积无差别;茶碱壳聚糖微球组能够显著改善支气管直径,与单纯哮喘模型组比较差异具有统计学意义(P＜0.05),而布地奈德组对支气管内直经无显著改善,与单纯模型组比较差异无统计学意义(P＞0.05).结论 茶碱气道缓释微球吸入可以抑制气道炎症反应,扩张支气管平滑肌.因此,有望成为吸入激素加长效β2受体激动剂的补充或替代药物.