载介孔二氧化硅纳米囊脂质体对磁共振T2加权成像的负性增强作用

目的 检测载介孔二氧化硅纳米囊脂质体(MSN-LIPO)的弛豫特性,并探索其增强磁共振成像(MRI)T2加权成像的功能.方法 在体外条件下,应用MRI扫描仪对不同含铁浓度的MSN-LIPO行MRI扫描,检测MSN-LIPO的弛豫特性.在体内条件下,建立6只BALB/c裸鼠皮下恶性胶质瘤模型,随机分为2组,分别经瘤内和静脉注射同一浓度的MSN-LIPO.并在注射前、后行MRI扫描,研究图像特征并对信号值进行统计学分析.结果 体外MRI显示,随着MSN-LIPO含铁浓度的增高,图像信号强度逐渐降低;绘制弛豫率曲线,1/T2和MSN-LIPO含铁浓度在一定范围内具有良好的线性关系,测得弛豫率(r2)为413.7 mmol-1·s-1.BAIB/c裸鼠恶性胶质瘤模型MRI显示,瘤内注射MSN-LIPO后肿瘤信号强度值为15.34±1.24,低于注射前的211.44±5.34,差异有统计学意义(t=36.38,P＜0.05);静脉注射MSN-LIPO后肿瘤信号强度值为179.00±4.35,低于注射前的235.99±5.17,差异有统计学意义(t=14.34,P＜0.05).结论 MSN-LIPO有良好的弛豫特性,在体内有良好的MRI T2加权肿瘤成像负性增强作用,具有MRI T2加权成像造影剂功能.

Mesoporous silica nanocapsules loaded liposomes negatively enhance magnetic resonance T2 weighted imaging

Objective To detect the relaxation property of mesoporous silica nanocapsules loaded liposomes (MSN-LIPO), and to explore their functions of enhancing MRI T₂ weighted imaging. Methods In vitro, MSN-LIPO with different iron concentrations were scanned by MRI system to detect their relaxation properties. In vivo, six BALB/c nude mouse models with subcutaneous malignant glioma were established and randomly divided into two groups, which were injected with the same concentration of MSN-LIPO intratumorally and intravenously, respectively. The mice in the two groups were scanned by MRI before and after injection, and the image characteristics were studied and the signal intensity of tumors was statistically analyzed. Results In vitro MRI imaging showed that the signal intensities of the images were gradually decreased with the increase of iron concentrations in MSN-LIPO, and 1/T₂ had a good linear relationship with the concentration within a certain range, with the relaxation rate (r₂) being 413.7 mmol^-1·s^-1. MRI imaging of BALB/c nude mouse models with malignant glioma showed that the signal intensity of the tumor after intra-tumor injection of MSN-LIPO was significantly lower than that before intra-tumor injection (15.34±1.24 vs 211.44±5.34, t=36.38, P<0.05), and the signal intensity of the tumor after intravenous injection of MSN-LIPO was significantly lower than that before intravenous injection (179.00±4.35 vs 235.99±5.17, t=14.34, P<0.05). Conclusion MSN-LIPO has good magnetic relaxation property and good MRI T₂ weighted contrast enhancement function in vivo, suggesting that it can be used as a MRI T₂ contrast agent.