pcDNA3.1-VEGF165转染BMSCs构建组织工程骨修复骨缺损的实验研究

目的：依据组织工程的原则,首先将pcDNA3.1-血管内皮生长因子（vascular endothelial growth factor, VEGF）165质粒转染至骨髓间充质干细胞（bone marrow stromal cells ,BMSCs）,然后将其与纳米羟基磷灰（nano-hydroxyapatite,n-HA) /羧甲基壳聚糖（carboxymethyl chitosan,CMCS）支架材料复合构建组织工程骨,观察该组织工程骨在兔桡骨骨缺损模型处的成骨能力及降解速度。 方法：采用化学共沉淀法制备纳米羟基磷灰石,以京尼平（Genipin）为交联剂,通过粒子沥滤结合冷冻干燥工艺制备纳米羟基磷灰石/羧甲基壳聚糖复合支架材料。采用扫描电镜观察其微观结构;三点弯曲法测试其力学性能;通过细胞形态分析测试其体外细胞毒性;激光共聚焦显微镜观察其荧光性能。根据设计的引物反转录合成VEGF165,pcDNA片段,构建pcDNA3.1-VEGF165质粒。骨髓间充质干细胞取自兔骨髓,培养、传代,采用电转法将 pcDNA3.1- VEGF165转至 BMSCs 然后与 n-HA/CMCS支架材料复合构建组织工程骨;建立动物模型将其植入兔桡侧,通过大体观察,X射线,HE染色及三点弯曲强度评价其成骨能力及降解速度。 结果：京尼平交联的n-HA/CMCS支架材料微观结构、力学性能与天然松质骨相似,可满足支架材料的要求;与戊二醛做交联剂所得支架相比,本研究所得支架生物毒性更小,更利于细胞的吸附与增殖,并且使用京尼平交联是支架材料具有自发荧光特征;成功构建出 pcDNA3．1-VEGFl65质粒,将其转至 BMSCs,并与n-HA/CMCS 复合构建组织工程骨。大体标本观察表明复合材料植入骨缺损处可见骨缺损处愈合良好,植入材料大部分已转化为自体骨组织仅少许未降解。X射线观察显示实验侧可见明显骨痂生成,骨髓腔形成,骨髓腔基本贯通。HE染色结果表明实验组骨缺损愈合,皮质骨形成,皮质主要由编织骨组成,部分由新生的骨单位构成,髓腔再通。 结论： pcDNA3.1-VEGF165转染BMSCs复合n-HA/CMCS支架材料具有生物相容性好、无毒副作用、促进局部微血管形成、加快骨缺损修复的作用,其降解速度与骨生长速度基本匹配;使用京尼平交联的支架不同于其他骨组织工程支架材料,其具有自发荧光特征。通过激光共聚焦显微镜可以清楚地观察到支架和细胞的界面,细胞的粘附特征,以及支架的微结构和降解时微结构特征变化。综上可知本研究所得复合骨是一种潜在的性能优良的骨修复材料。     

栀子苷治疗阿尔采末病及神经保护的分子机制研究进展

阿尔采末病(AD)是一种中枢神经退行性疾病,以学习记忆和认知功能障碍为主要表现。Aβ毒性级联损伤是其核心病理之一。栀子苷是栀子的主要有效成分,其苷元为京尼平。实验研究表明,栀子苷和京尼平具有抗Aβ毒性损伤、抗氧化应激,抗内质网应激、抗炎症反应及促进神经生长作用。从分子作用机制角度综述近年来栀子苷及京尼平治疗AD和神经保护作用的有关文献,以期为栀子治疗AD提供借鉴。     

Biotransformation of geniposide by human intestinal microflora on cytotoxicity against HepG2 cells

Intestinal microflora (IM) is able to produce toxic and carcinogenic metabolites and induce more potent cytotoxicity against cells than non-metabolites. This study was performed to investigate the cytotoxic responses of geniposide (GS) and its metabolite and to determine the role of metabolism by IM in GS-induced cytotoxicity. Genipin (GP), a GS metabolite, increased cytotoxic effects in cells, but GS did not. Following GS incubation with IM for metabolic activation, increased cytotoxicity was detected compared to GS. Western blot analysis revealed that the activated GS inhibited Bcl-2 expression with a subsequent increase in Bax expression. Likewise, GS activation by IM stimulated caspase-3 and the production of reactive oxygen species (ROS). In addition, activated GS-induced apoptosis was confirmed by apoptosis and ROS assays; N-acetyl-l-cysteine (NAC) suppressed ROS production and apoptotic cell death. Activated GS induced sustained JNK phosphorylation. Moreover, activated GS-induced cell death was reversed by SP600125. Taken together, these findings suggest that human IM is able to metabolize GS into GP, and the related biological activities induce apoptosis through ROS/JNK signaling.     

栀子药效成分京尼平的结构改造

目的 对京尼平(genipin)的结构进行改造以阐明其药效结构。方法 以京尼平为原料,通过Swern 反应和选择性还原反应合成目标化合物,其结构经现代波谱方法鉴定。结果与结论 合成了3 个京尼平衍生物,单步收率在 77%~90%;3 个化合物的结构均经 ¹H-NMR 和¹³C-NMR 和 MS 谱确证。     

胶原神经导管对外周神经缺损修复的实验研究

目的探讨组织工程化胶原神经导管的构建及对外周神经缺损的修复。方法分别取10g胶原蛋白利用自制模具分别制备含0.25g川芎嗪和无川芎嗪的胶原神经导管(2%京尼平交联);对交联前后的胶原神经导管进行拉伸实验并评价其力学特性;用扫描电子显微镜观察胶原神经导管交联前后的空间结构;将大鼠骨髓间充质干细胞(MSC)与细胞外基质(ECM)混合后接种于导管内腔,用扫描电子显微镜观察细胞与材料的复合情况;质量浓度10g/L的川芎嗪诱导MSC7d后,荧光免疫化学方法鉴定MSC分化为神经元细胞;用8只Wister大鼠复制坐骨神经10mm缺损模型,复合MSC的神经导管连接缺损神经,其中4只为无中药导管作为对照,90d后处死大鼠观察再生神经形态,免疫组织化学鉴定其功能。结果京尼平交联前后胶原纤维结构发生明显改变,交联后胶原纤维排列致密,胶原纤维之间形成不规则孔隙且韧性增强;力学实验结果表明:交联前后的胶原神经导管的最大载荷和断裂载荷分别为(0.23±0.09)、(0.20±0.12)N和(0.76±0.15)、(0.69±0.17)N,两者差异具有显著统计学意义(P﹤0.01);川芎嗪能促进MSC表达神经元特异性烯醇酶并向神经细胞分化;神经导管与MSC复合培养两者具有良好的组织相容性;复合川芎嗪的胶原神经导管能促进缺损神经的修复。结论构建的组织工程化胶原神经导管能有效修复外周神经缺损。     

Swelling and Viscoelastic Characterisation of pH‐Responsive Chitosan Hydrogels for Targeted Drug Delivery

Chitosan hydrogels have been investigated as potential vehicles for targeted drug delivery. The gels were permanently crosslinked with conventional crosslinking agent, glutaraldehyde and the naturally occurring non‐toxic crosslinking agent genipin in both the monomer and polymerised states. The swelling behaviour of all the gels was highly pH dependent. The gels with the lowest crosslink density not only had an increased rate of diffusion but also an increased total release. It is shown that by altering the type and degree of crosslinking in a chitosan hydrogel it is possible to change the swelling and elastic characteristics of the material, which could be of potential interest as an environment responsive drug delivery matrix.

     

京尼平对胃癌SGC 7901细胞体外增殖、侵袭能力和凋亡的影响及其机制

目的：探讨京尼平（GP）对胃癌SGC 7901细胞的调控作用,并阐明其作用机制点。方法：取对数生长期的SGC 7901细胞,分为对照组和不同浓度（5、10、和20 mg·L^-1）GP组,采用MTT法检测不同时间点（24、48和72 h）SGC 7901细胞体外增殖抑制率,应用Transwell小室细胞侵袭实验检测SGC 7901细胞体外侵袭能力,应用Western blotting法检测SGC 7901细胞中Bcl-2、Bax和caspase-3蛋白表达水平。结果：MTT法检测,与对照组比较,作用不同时间后不同浓度GP组SGC 7901细胞增殖抑制率明显升高（P<0.05）;Transwell小室细胞侵袭实验,与对照组比较,作用72h后,10和20 mg·L^-1GP组穿膜细胞数明显降低（P<0.01）;Western blotting法检测,与对照组比较,作用72 h后,20 mg·L^-1GP组SGC 7901细胞中Bcl-2蛋白表达水平降低（P<0.01）,caspase-3和Bax蛋白表达水平升高（P<0.05）。结论：GP能够抑制SGC 7901细胞的体外增殖和侵袭能力,且能够诱导细胞凋亡,其机制可能与调节Bcl-2、Bax和caspase-3蛋白表达有关。     

Investigation on Endogenous Metabolites in Pancreas of Diabetic Rats after Treatment by Genipin through 1H-NMR-based Metabolomic Profiles

Objective To investigate the change rules of endogenous metabolites in pancreas of the diabetic rats, and to explore the mechanism of genipin treatment for diabetes rats. Methods Metabolomic method based on ~1H-NMR was applied, the diabetic rat model was prepared by ip injecting alloxan, and the high-, mid-, and low-dose genipin or metformin hydrochloride was ig injected as well as the rats in control and model groups were given the same volume of normal saline for 2 weeks. The pancreases of rats were collected and ~1H-NMR test was conducted, the metabolomic technology was adopted to analyze the endogenous metabolite changes in pancreas. Results The high-dose genipin possessed a better hypoglycemic effect, which could increase the contents of isoleucine, phosphatidylcholine, and phosphatidylethanolamine, and significantly reduce the contents of lactic acid, alanine, glutamine, aspartic acid, and creatine in pancreas of diabetic rats. Conclusion This study provided a theoretical basis for further exploration on the pathogenesis of diabetes and the mechanism of genipin for treatment of diabetes.