放射性^(131)I标记胶原-壳聚糖复合微球的制备及其杀伤肝癌细胞的体内研究

Preparation of ^(131)I Labeled Collagen-Chitosan Microspheres and It's Antitumor Effect on Human Liver Cancer

目的用壳聚糖及胶原这两种可降解生物材料,制备能用于^(131)I标记的放射性核素微球并探究其对肝癌的治疗效果。方法以Ⅰ型胶原蛋白和壳聚糖为主要材料,戊二醛为交联剂,利用乳化交联法制备胶原-壳聚糖复合微球。电镜下观察微球表征,测量并统计微球的粒径。通过氯胺T法对微球进行^(131)I标记,计算标记率。等量^(131)I-微球分别置于PBS和人血清中192h,探究其体外稳定性。BALB/C裸鼠皮下一次性注射人肝癌细胞HepG2约106个,构建裸鼠人肝癌细胞模型。28d后,^(131)I-微球、空白微球、PBS分别一次性注入荷人肝癌裸鼠模型的皮下瘤中(每组5只),治疗7d后处死裸鼠。取血和心、肺、肝、脾、胃、小肠、肾、肌肉、脑、骨、甲状腺、皮下肝癌组织检测标记微球在裸鼠体内的分布,同时对皮下肝癌组织进行组织病理学HE染色,检测标记微球对肝癌细胞的杀伤效果。结果本研究成功制得胶原-壳聚糖微球,电镜显示微球成球性好,表面光滑,粒径较均匀,平均粒径为(5.1±1.2)μm。其^(131)I标记率为86.10%,置于PBS及血清192h后,碘标记率分别为92.00%、83.00%,^(131)I-微球依然保持高稳定性。治疗7d后裸鼠体内分布实验显示放射性主要集中在皮下肿瘤组织,其他组织几乎没有放射性计数。皮下肿瘤组织病理切片显示PBS组见大量肝癌细胞,标记微球后周围的肝癌细胞大量死亡,空白微球组中微球周围仅有少量的炎性细胞,未引起局部强烈的免疫反应。后两组微球均未见明显降解。结论本研究制得的胶原-壳聚糖具有很高的^(131)I标记率、体内外稳定性及良好的肿瘤杀伤效果。

Objective To prepare iodine-131 （131Ⅰ） labeled biodegradable microspheres with chitosan and collagen for treating liver cancer. Methods Collagen-chitosan microspheres （CCMSs） were prepared with type-I collagen and chitosan using emulsification-chemical cross-linking method. The size of the CCMSs were determined by electron microscope. 131Ⅰ-CCMSs were achieved using Chloramine T. The labelling rate of 131Ⅰ was recorded. The stability of 131Ⅰ-CCMSs in vitro were evaluated in PBS or human blood serum through 192 h incubation. The HepG2 model was established in nude mice 28 d after subcutaneous injection of 106 HepG2 ceils. The model mice were sacrificed 7 d after injection of 131Ⅰ-CCMSs, blank microspheres, or PBS （five mice in each group） into the HepG2 tumor xenografts. Samples of various organs were collected to determine the distribution of 131Ⅰ-CCMSs. The curative effect of 131Ⅰ-CCMSs on liver cancer was assessed by staining with HE for histological analyses. Results CCMSs were synthesized with a smooth and spherical shape and an average diameter of （5. 1±1.2）μm. A radiolabeling rate of 86. 10% was achieved. 131Ⅰ radio-loading remained stable： 92.00% in saline and 83.00% in human serum after 192 h incubation. 131Ⅰ was mainly concentrated in the subcutaneous tumor tissues. Potent curative effects of 131Ⅰ-CCMSs on subcutaneous tumor tissues were demonstrated. Conclusion Biodegradable CCMSs were successfully prepared and radiolabeled. The 131Ⅰ-CCMSs exhibited potential curative effects on liver cancer, with high stability in vitro and in vivo.