Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
Sci Rep. 2020 Oct 29;10(1):18655. doi: 10.1038/s41598-020-73923-2.
The objective of this study is to investigate the signal changes and optimal scanning concentration of MRI in tumor tissues of tumor-bearing nude mice by SPIO-shRNA molecular probes. 30 BALB/c tumor-bearing nude mice were randomly divided into 5 groups with 6 mice in each group. At the given scanning time (before and 27 h after injection), the caudal vein was respectively injected with iron content of 6 mg·kg, 12 mg·kg, 18 mg·kg, 24 mg·kg, and 30 mg·kg, and MR examination was simultaneously performed to measure signal intensity changes of tumor tissue and contralateral muscle tissue in each concentration group. After each examination above, the nude mice were sacrificed immediately, and the tumor and muscle tissues were removed for HE and Prussian blue staining,and observed under light microscope. Nude mice in 6 mg, 12 mg and 18 mg groups all survived after probe injection, but some nude mice died in 24 mg and 30 mg groups after probe injection or during scanning. The signal changes of T2WI and T2*WI sequences were the most obvious in MR scanning sequences. Compared with other groups, the signal intensity of the tumor tissue in 18 mg, 24 mg and 30 mg groups were most obvious (P < 0.05), while the 18 mg, 24 mg and 30 mg groups reached no statistical difference (P > 0.05 ); HE staining indicated that structural disorder of tumor tissue as well as increase of nuclear atypia. Prussian Blue staining showed that blue-stained iron particles were present in each experimental group,and the most densely distributed were in 18 mg,24 mg and 30 mg groups. Tumor tissue could be well labeled with SPIO-shRNA molecular probes, and the optimal MR scanning concentration (iron content) is 18 mg·kg.
本研究旨在通过 SPIO-shRNA 分子探针研究荷瘤裸鼠肿瘤组织的 MRI 信号变化及最佳扫描浓度。30 只 BALB/c 荷瘤裸鼠随机分为 5 组，每组 6 只。在给定的扫描时间（注射前和注射后 27 h），分别经尾静脉注入铁含量为 6、12、18、24 和 30 mg·kg 的探针，同时进行 MR 检查，测量各浓度组肿瘤组织和对侧肌肉组织的信号强度变化。每次检查后，立即处死裸鼠，取出肿瘤和肌肉组织，行 HE 和普鲁士蓝染色，光镜下观察。6、12 和 18 mg 组探针注射后所有裸鼠均存活，但 24 和 30 mg 组部分裸鼠探针注射后或扫描过程中死亡。MR 扫描序列中 T2WI 和 T2*WI 序列的信号变化最明显。与其他组相比，18、24 和 30 mg 组肿瘤组织的信号强度最明显（P<0.05），而 18、24 和 30 mg 组之间无统计学差异（P>0.05）；HE 染色显示肿瘤组织结构紊乱，核异型性增加。普鲁士蓝染色显示各组均有蓝色染色的铁颗粒，18、24 和 30 mg 组分布最密集。SPIO-shRNA 分子探针可良好标记肿瘤组织，最佳 MR 扫描浓度（铁含量）为 18 mg·kg。
