Application of sodium alginate microspheres in ischemic stroke modeling in miniature pigs

The miniature pig is an optimal animal model for studying nervous system disease because of its physiologic and pathologic features. However, the rete mirabile composed of arteries and veins at the skull base limits their application as a model of ischemic stroke by middle cerebral artery occlusion. The present study investigated the possibility of establishing an ischemic stroke model in the miniature pig by blocking the skull base retia with sodium alginate microspheres. Three Bama miniature pigs were used. Using the monitor of C-arm X-ray machine, sodium alginate microspheres (100-300 μm), a novel embolic material, were injected through the femoral artery, aortic arch, common carotid artery, ascending pharyngeal artery and the retia. Results were evaluated using carotid arteriography, MRI, behavior observation and histology. The unilateral rete mirabile was completely blocked, resulting in disturbance in blood supply to the basal ganglia, astasia of the right hind limb and salivation. MRI and hematoxylin-eosin staining showed an evident infarction focus in the basal ganglia. These findings indicate that sodium alginate microspheres are a suitable embolic material for blocking the skull base retia in miniature pigs to establish an ischemic stroke models.     

海藻酸钙/枸杞多糖凝胶微球对小鼠骨质疏松的作用研究

目的研究海藻酸钙(ALG-Ca)/枸杞多糖(LBPs)凝胶微球对小鼠骨质疏松的作用。方法采用静电液滴法制备ALG-Ca凝胶微球、ALG-Ca/LBPs凝胶微球,用扫描电镜观察微球结构。建立去卵巢小鼠骨质疏松模型,随机分为假手术组、模型组、单纯ALG-Ca微球组、单纯LBPs组、ALG-Ca/LBPs凝胶微球组,每组8只,每日灌胃1次,干预时间为12周,对各组小鼠股骨行HE染色观察骨组织形态变化,Micro-CT检测并经三维重建获得骨组织微观结构,对小鼠血清骨钙素(BGP)、血清碱性磷酸酶(BALP)、1型胶原羧基末端肽(CTX-1)进行检测。结果扫描电镜观察示凝胶微球呈均匀一致的微球形结构;OVX+LBPs、OVX+ALG-Ca/LBPs组的BGP、BALP、CTX-1均低于OVX+PBS组(P<0.05);OVX+LBPs、OVX+ALG-Ca/LBPs组骨体积分数(BV/TV)、骨小梁数目(Tb.N)及骨小梁厚度(Tb.Th)均高于OVX+PBS组(P<0.05),骨小梁间隙(Tb.Sp)小于OVX+PBS组(P<0.05),以OVX+ALG-Ca/LBPs组为最佳(P<0.01)。结论ALG-Ca凝胶微球是LBPs治疗骨质疏松的良好药物缓释载体;LBPs为天然植物成分,通过LBPs/ALG-Ca凝胶微球可以改善骨质疏松小鼠的骨代谢及骨微结构。     

5-FU纳米微粒的制备及其释药特性研究

目的 制备一种新型的载氟尿嘧啶(5-FU)纳米微粒并对其体内释药特性进行研究.方法 运用聚合物交联法制备出壳聚糖载氟尿嘧啶纳米粒,通过扫描电镜、激光粒度分析仪对其表征进行检测,紫外分光光度法测定载药量,高效液相色谱法检测体内的释药特性.结果 壳聚糖载氟尿嘧啶纳米粒呈圆形或椭圆形,分散性良好,粒径在120～150nm;载药量为31.000%±0.001%;壳聚糖-5-FU纳米粒注射入兔体内后,初期突释相约在1.5h,峰浓度为5 069.6μg/L,随即进入缓释相,浓度维持在76μg/L,时间长达48h.结论 壳聚糖纳米药物载体可改变5-FU在体内的药代动力学行为,延长其循环时间,具有良好的缓释作用.     

羊栖菜中褐藻酸钠的脱色纯化工艺及其结构成分研究

研究了羊栖菜中褐藻酸钠的脱色纯化工艺并测定了其组成与相对分子质量.结果表明褐藻酸钠脱色纯化的最佳工艺条件为3%(质量分数)甲醛溶液预浸泡,10%(质量分数)HCl溶液沉淀分离出褐藻胶,1 g/dL的Na2CO3溶液中和,10%(体积分数) NaClO溶液进行脱色.通过纯化工艺制得的褐藻酸钠的纯度为95.1%,褐藻酸钠分子中β-D-甘露糖醛酸与α-L-古罗糖醛酸的量的比值为0.75,平均聚合度DP为101,粘均相对分子质量为21 963.     

庆大霉素-藻酸钙三维缓释微球的药物释放研究

目的研制庆大霉素一藻酸钙三维缓释微球并调控其庆大霉素的释放。使其达到长期局部抗菌的效果。方法制作不同浓度T、S、U组庆大霉素-藻酸钙缓释凝珠,与庆大霉素-骨水泥颗粒Y组进行庆大霉索释放情况比较。通过不同时间点抽取浸泡液,送紫外分光光度法（UV）及金黄色葡萄球菌（SA）培养检测,由此计算出各组包封率、释放率,绘制庆大霉素释放曲线。结果4组样品（微生物法）的包封率及30d药物释放率分别为：U组（53．99％、36．31％）,S组（39．62％、27．55％）。T组（34．20％、30．83％）,Y组（100．00％、48．49％）。U组的包封率较高,30d释放庆大霉素的总量较大,更接近Y组。4组间差异有统计学意义（P〈0．01）。U、Y组庆大霉素的释放明显高于S、T组的释放。各组30d内庆大霉素的浓度几乎都能超过金黄色葡萄球菌的最低抑菌浓度（MIC）．即〉2μg／mI。结论U组载药缓释凝珠30d内的庆大霉索释放较为理想。可作为BMSCs的三维培养支架。     

Effects of 3-dimensional Bioprinting Alginate/Gelatin Hydrogel Scaffold Extract on Proliferation and Differentiation of Human Dental Pulp Stem Cells

IntroductionAlginate/gelatin hydrogel (Alg-Gel) scaffold has been applied in tissue engineering, but the research on its application in dental tissues regeneration is still lacking. We investigated the effect of this scaffold on human dental pulp stem cells (hDPSCs).MethodshDPSCs were cultured in both Alg-Gel and 3D-printed Alg-Gel scaffolds. Cell growth and adhesion were compared using fluorescein isothiocyanate–phalloidin staining and scanning electron microscopic micrographs. Changes in the proliferation in hDPSCs cultured in the complete culture medium containing aqueous extracts of the Alg-Gel or 3D-printed Alg-Gel scaffolds were examined using Cell Counting Kit-8 assay and flow cytometry analysis. Cells were cultured in the mineralization medium containing aqueous extracts of the Alg-Gel or 3D-printed Alg-Gel scaffolds for 7 or 14 days, and the differentiation of cells was shown by alizarin red S staining and alkaline phosphatase staining. The messenger RNA and protein expression of mineralization-related genes were detected with real-time polymerase chain reaction and Western blotting. Elemental analysis was used to test the material extract composition.ResultsMore cells were grown and adhered to the 3D-printed Alg-Gel scaffolds than the Alg-Gel scaffolds. The aqueous extracts of 3D-printed scaffolds can promote cell proliferation, and compared with Alg-Gel scaffolds, the extracts of 3D-printed scaffolds were more effective. Compared with the negative control group, 3D-printed Alg-Gel scaffold and Alg-Gel scaffold aqueous extracts promoted osteogenic/odontoblastic differentiation of hDPSCs with the enhanced formation of bone-like nodules and the alkaline phosphatase staining. The expression of mineralization-related genes was also up-regulated. 3D-printed scaffold aqueous extract contained more calcium and phosphorus ions than the Alg-Gel scaffold.ConclusionsThese findings suggest that compared with the Alg-Gel scaffold, 3D-printed Alg-Gel is more suitable for the growth of hDPSCs, and the scaffold extracts can better promote cell proliferation and differentiation.     

Effect of allogeneic Schwann cell transplantation on peripheral nerve regeneration

Transplantation of allogeneic Schwann cells (SC) would make it feasible to reconstruct immediately peripheral nerve defects, compared to using autologous SC; however, this treatment modality has not been adequately evaluated. The aim of this study was to characterize and compare the effects of allogeneic versus syngeneic SC transplantation following peripheral nerve injury. Polyhydroxybutyrate conduits were used to bridge a 10-mm gap in the rat sciatic nerve. The conduits were filled with alginate hydrogel with or without cultured allogeneic or syngeneic genetically labeled SC, without the use of immunosuppressive therapy, and examined after 2, 3, and 6 weeks with 5-bromo-4-chloro-3-indoyl-beta-D-galactosidase chemical staining and immunohistochemistry to quantify SC migration into the conduit, axonal regeneration, the state of SC differentiation, and the expression of major histocompatibility complexes (MHC) I and II, as well as to quantify macrophage and B- and T-lymphocyte infiltration. Allogeneic SC were rejected by 6 weeks, whereas syngeneic SC could still be identified. Allogeneic and syngeneic SC equally enhanced the axonal regeneration distance but the quantity of axons was greater using syngeneic SC. The ingrowth of SC into the conduits containing allogeneic SC was similar to that observed in the presence of syngeneic SC, indicating the absence of deleterious immune response. SC continued to express phenotypic markers of nonmyelination and these were highest in conduits with allogeneic SC. Expression of MHC I and II was higher in the conduits with allogeneic SC at 3 weeks and without significant difference in the number of macrophages and lymphocytes, except at 6 weeks, when there was a larger number of lymphocytes using syngeneic SC. In conclusion, allogeneic SC enhanced axonal regeneration distance and did not induce a deleterious immune response. In a clinical setting the immediate availability of allogeneic SC for transplantation may compensate for the better outcome achieved by the use of autologous SC that require a longer preparation time in culture.     

Mucosal co-delivery of ketorolac and lidocaine using polymeric wafers for dental application

The current study aimed to investigate the effectiveness of a developed sodium alginate and polyvinylpyrrolidone K-25 (PVP K-25) polymeric wafer for the co-delivery of ketorolac and lidocaine to soft tissues for healing and pain control following gingivectomy. Nine ketorolac/lidocaine lyophilized wafers were formulated and assessed for their hydration capacity, mucoadhesion ability and in vitro release profile to select the optimum system for further clinical investigation. Wafer F6 containing 2:1 sodium alginate to PVP K-25 and 10% glycerol showed optimum properties and was selected for the clinical study. Twenty patients were included in the study and the ketorolac/lidocaine wafer was assessed versus a market product. Visual pain analog was evaluated daily for the first week and wound healing index was evaluated for one week, two weeks and one month following the procedure. The developed ketorolac/lidocaine polymeric wafer proved to be an effective method of reducing pain and discomfort together with enhancing wound healing following gingivectomy.     

聚己内酯/海藻酸钠/壳聚糖材料制备 组织工程椎间盘双相支架

摘要：目的 以聚己内酯（PCL）、海藻酸钠、壳聚糖为材料,研制椎间盘双相支架,并评估其作为组织工程椎间盘 的可行性。方法 聚己内酯作为原料,采用熔融电纺法制备取向性多孔纤维环支架,将海藻酸钠/壳聚糖水凝胶注入 到中空的纤维环（AF）支架中央合成双相椎间盘支架。通过体式显微镜、扫描电镜观测双相支架的结构、孔径、孔隙 率;人脐带干细胞复合双相支架体外培养7 d,用死活细胞染色法评价生物相容性,CCK-8实验测定细胞增殖情况,力 学加载仪器测量双相支架的压缩弹性模量。结果 体式显微镜和扫描电镜可见纤维环相成菱形多孔结构,髓核相 （NP）呈不规则多孔结构;纤维环相和髓核相孔径分别为（225.6±3.9）μm、（205.5±5.2）μm,孔隙率分别为（74.17± 0.39）%、（85.52±0.48）%,支架扫描电镜可见细胞黏附在支架表面,周围有细胞外基质分泌;死活细胞染色显示无死 细胞;CCK-8检测结果显示人脐带干细胞具有良好的增殖活性,压缩弹性模量（173.24±44.93）kPa。结论 以聚己内 酯、海藻酸钠、壳聚糖为材料制备的椎间盘双相支架,具有良好的孔径、孔隙率和细胞相容性,支架间结合紧密,具有 三维网络结构,优良的力学特性,是构建组织工程椎间盘理想载体。