在壳聚糖(CS)表面修饰疏水基团辛基形成辛基壳聚糖(OC),然后再修饰亲水基团聚乙二醇(PEG)、肿瘤靶向配体氨基葡萄糖(DG)和穿膜肽九聚精氨酸(9R),形成DG和9R共同修饰的、同时具有肿瘤靶向性及穿膜效应的壳聚糖纳米胶束(DG/9R-PEG-OC)。核磁共振光谱分析及聚丙烯酰胺凝胶电泳检测结果证实了DG/9R-PEG-OC的成功制备;测得壳聚糖纳米胶束的粒径为151.8 nm左右、Zeta电位约为16.5 m V;透射电子显微镜照片显示该壳聚糖纳米胶束为均匀的球形结构;紫外分光光度法测定该载体的荧光素载药量约为28.2%,包封率约为75.0%,释药实验表明壳聚糖胶束具有良好的缓释作用;荧光显微镜观察显示,该DG/9R-PEG-OC胶束对肿瘤细胞尤其是葡萄糖受体高表达的肿瘤细胞Hep G2具有较好的靶向性及细胞穿膜效应。故DG/9R-PEG-OC胶束可作为脂溶性抗肿瘤药物的载体用于肿瘤的靶向化学治疗。
Objective To screen and identify differentially expressed genes in the dorsal root ganglion （DRG） in early experimental diabetic rats. Methods Diabetic model rats were induced by single intraperitoneal injection of streptozotocin （STZ）. At the second week after STZ injection, the sensory nerve conduction velocities （SNCV） of sciatic nerve were measured as an indicator of neuropathy. The technique of silver-staining mRNA differential display polymerase chain reaction （DD-PCR） was used to detect the levels of differentially expressed genes in rat DRG. The cDNA fragments that displayed differentially were identified by reverse-hybridization, cloned and sequenced subsequently, and then confirmed by Northern blot. Results The SNCV in the diabetic model group [n = 9, （45.25±10.38） m/s] reduced obviously compared with the control group [n = 8, （60.10± 11.92） m/s] （P 〈 0.05）. Seven distinct cDNA clones, one was up-regulated gene and the others were downregulated ones, were isolated by silver-staining mRNA differential display method and confirmed by Northern blot. According to the results of sequence alignment with GenBank data, majority of the clones had no significant sequence similarity to previously reported genes except only one that showed high homology to 6-pyruvoyl-tetrahydropterin synthase mRNA （accession No., BC059140）, which had not been reported to relate to diabetic neuropathy. Conclusion These differentially expressed genes in the diabetic DRG may contribute to the pathogenesis of diabetic peripheral neuropathy.
