吲哚菁绿在乳腺癌肿瘤坏死模型中的光学成像研究

Optical imaging study of indo cyanine green in tumor necrosis model of breast cancer

目的探讨吲哚菁绿(indo cyanine green,ICG)在小鼠乳腺癌肿瘤坏死模型光学成像中的可行性及其效果。方法腋下局部注射95%无水乙醇1μL造成小鼠局部组织坏死后,于尾静脉注射0.5 mg/kg ICG 100μL,通过荧光活体成像系统(in vivo imaging system,IVIS)观察注射ICG后2 h和24 h时ICG的体内分布情况,初步验证ICG的坏死亲和性。通过将人乳腺癌MDA-MB-231荧光素酶基因稳转株MDA-MB-231-Luc细胞接种于裸鼠右侧腋下构建乳腺癌荷瘤小鼠模型。通过尾静脉注射血管破坏性药物考布他汀A4磷酸脂(combretastatin A4 phosphate,CA4P)100 mg/kg 100μL 24 h构建乳腺癌肿瘤坏死模型。对肿瘤坏死小鼠于尾静脉注入0.5 mg/kg ICG 100μL,通过IVIS对荷瘤小鼠分别在注射ICG后2 h和24 h时进行自体荧光及近红外荧光成像,评估ICG在乳腺癌肿瘤坏死模型中的分布及光学成像效果。将小鼠分为对照组、ICG组和ICG+CA4P组,ICG+CA4P组为上述用于光学成像的肿瘤坏死小鼠,对照组与ICG+CA4P组同样建模但仅给予尾静脉注射生理盐水100μL而未注射ICG及CA4P,ICG组与ICG+CA4P组同样建模后仅于尾静脉注入0.5 mg/kg ICG 100μL而未给予CA4P。三组分别于给药后0、3、7和10 d测量肿瘤体积。结果在无水乙醇造成的局部坏死模型中,在尾静脉注射ICG后2 h时,IVIS下见ICG主要分布于肝脏及坏死区域。在24 h时,肝脏内的ICG逐渐代谢排出,而坏死组织处ICG在坏死亲和性的作用下,ICG聚集并潴留在坏死组织中,荧光成像结果中呈现出高信号。在CA4P造成的乳腺癌肿瘤坏死模型中,在注射ICG后24 h时,ICG在种植瘤及转移瘤区域潴留富集,自体荧光及近红外荧光成像结果高度重合。在ICG+CA4P组中,肿瘤的生长受到抑制,与对照组比较,在3、7和10 d时差异均具有统计学意义(均P<0.05),与ICG组比较在7和10 d时差异均具有统计学意义(均P<0.05)。结论ICG可在CA4P介导下的肿瘤坏死模型中高度聚集,可实现良好的光学成像效果,在肿瘤转移早期检测及手术导航中具有良好的应用前景。

Objective To investigate the feasibility and effect of indo cyanine green(ICG)in the optical imaging of breast cancer tumor necrosis mice model.Methods Local necrosis mice was established by injecting 1μL 95%anhydrous alcohol in armpit.To verify the ne-crosis affinity of ICG,100μL 0.5 mg/kg ICG was injected through the tail vein of the local necrosis mice,and the in vivo distribution was observed by a spectrum in vivo imaging system(IVIS)2 hours and 24 hours after ICG injection.To establish a subcutaneous xenotrans-planted toumor model of breast cancer,MDA-MB-231-Luc cell line was grafted in right armpit of nude mice.The tumor necrosis model of breast cancer was established by injecting the vascular destructive drug combretastatin A4 phosphate(CA4P,100 mg/kg 100μL)into the tail vein for 24 h.Tumor necrosis mice were injected with 100μL 0.5 mg/kg ICG into the tail vein,and the tumor-bearing mice were performed with the autofluorescence and near-infrared fluorescence imaging at 2 h and 24 h after ICG injection by IVIS to evaluate the distribution and optical imaging effects of ICG in the breast cancer tumor necrosis model.The mice were divided into control group,ICG group,and ICG+CA4P group.The ICG+CA4P group was the tumor necrosis mice used for optical imaging above.The mice in the control group were established in the same way as the ICG+CA4P group,but were only injected with 100μL normal saline into the tail vein instead of ICG and CA4P.The mice in the ICG group were established also in the same way as the ICG+CA4P group,but were only injected with 100μL 0.5 mg/kg ICG into the tail vein without CA4P.The tumors were measured at 0,3,7,and 10 days after administration,and the changes in tumor volume were observed.Results In the local necrosis model caused by anhydrous alcohol,the imaging results of IVIS showed that 2 hours after ICG injection via the tail vein,ICG was mainly distributed in the liver and necrotic areas,and 24 hours after ICG injection,ICG in the liver was gradually metabolized and excreted,while ICG in the necrotic areas was accumulated in the necrotic tissues due to the necrosis affinity of ICG.In the CA4P-induced breast cancer tumor necrosis model,24 hours after injection of ICG,ICG was retained and enriched in implanted and metastatic tumor areas,and the results of autofluorescence and near-infrared fluorescence imaging were highly coincident.In the ICG+CA4P group,the tumor growth was inhibited,which was significantly different from that of the control group at 3,7,and 10 days,and from that of the ICG group at 7 and 10 days(all P<0.05).Conclusion By highly concentrated in the tumor necrosis model mediated by CA4P,ICG shows excellent optical imaging effect in the breast cancer tumor necrosis model and has a good application prospect in the early detection of tumor metastasis and surgical navigation.