磁性载PTX-OA微泡双模式成像及其对小鼠宫颈癌的研究

Paclitaxel-Oleanolic acid-loaded superparamagnetic microbubbles:dual-mode imaging and its effect on U14 transplantation tumor in mice

目的:探讨多功能高分子微泡(MPMBs)双模式成像效能及其联合超声对小鼠宫颈癌(U14细胞株)组织增殖、相关基因及凋亡蛋白表达的影响。方法:采用低温真空干燥技术和双乳剂挥发法制备磁性MPMBs微泡,观察其体内、外超声/磁共振显影的能力并检测其一般物理特性。建立小鼠U14皮下移植瘤模型,分别给予不同处理,计算各组抑瘤率。免疫组化法及实时PCR法检测Bax、Bcl-2蛋白及基因表达。结果:MPMB显示较好的超声、磁共振显影效果;自制微泡呈圆形,表面光滑,平均粒径2.50μm,紫外分光光度计分析药物浓度:紫杉醇的载药量为9.18%,包封率为85.27%,齐墩果酸的载药量为8.03%,包封率为80.56%(略低于单独载药的载药量)。磁性共载紫杉醇及齐墩果酸组肿瘤生长最缓慢,肿瘤质量、体积明显下降(P<0.05),肿瘤组织HE染色分别呈不同程度的坏死,Bax表达上调,Bcl-2表达下调(P<0.05)。结论:MPMBs具备良好的超声、磁共振显影效能。MPMBs联合超声可调节肿瘤组织Bax及Bcl-2蛋白及基因的表达比例,提高凋亡率,有效抑制小鼠U14皮下移植瘤的生长。

Objective:To investigate the dual-mode imaging ability of multifunctional polymer microbubbles(MPMBs)and to observe its effect on m ice,proliferation and apoptosis in U14 cells.M eth o d s:The MPMBs were made by double emulsion and vacuum freeze-drying.Enhancement of ultrasound(US)/magnetic resonance(MR)imaging were evaluated in vitro.Its general characteristics were tested.To established U14 transplantation tumor models in m ice,then the mice were treated with different method.The tumor growth curve was drew according to the tumor volume.The rate of tumor inhibition was calculated after sacrificing the animals at the end of experiment.The expressions of Bax,bcl-2 in tumor tissues were examined on HE staining,Immunohistochemistry assay and RT-PCR.Results:The MPMBs were stable with favourable US/MR dual-mode imaging capablity,the microbubbles were round and uniform with the mean size of 2.50μm,the drug loading and encapsulation efficiency of Paclitaxel-oleanolic acid-loaded magnetic microbubbles were 9.18%,8.03%and 85.27%,80.56%respectively.Compared with control group,the tumors of Paclitaxel-oleanolic acid-loaded magnetic microbubbles plus ultrasound group grew the most slowly,tumor volume and weight were significantly decreased,the group showed varying degrees of degeneration and necrosis in HE staining,Bcl-2 expression decreased,Bax expression increased(P<0.05).Conclusions:US/MR dual-mode imaging showed its good property.Ultrasound-mediated Paclitaxel-oleanolic acid-loaded magnetic microbubbles can chang the expressions of bax,Bcl-2 and promote apoptosis of the tumor cells,inhibit the growth of U14 transplantation tumor in mice.