[Establishing the nude mice bone metastasis model of lung adenocarcinoma and applying MicroCT into the observation].

Background And Objective: 50%-70% of patients with advanced lung cancer will develop bone metastases. The aim of this study is to establish the nude mice bone metastasis model of lung adenocarcinoma using A549, H1299, SPC-A-1 and XL-2, all of which own different invasion and migration abilities in vitro and supervise the bone metastases by MicroCT.

Methods: fifty BALB/C-nu/nu nude mice were grouped into five groups on average randomly. Cells of the four cell lines were injected into the left cardiac ventricle of mice in the four experimental groups (0.2 mL/mouse) respectively; meanwhile, mice in the control group were injected with normal saline (0.2 mL/mouse) in the same manner. Periodical radiological examination was carried out to supervise the variation of the mice since the second week after injection. When mice in each group became thin obviously, end the experiment of this group. Before the end, pathological sections of bone tissues were made. We classified the bone metastatic sites into axial skeleton and limb bone, in order to compare the metastatic rates of these two different parts. The bone metastatic abilities of the four cell lines was statistically analyzed by comparing the average time cost in the appearance of bone metastases and the percentage of bone metastases among the experimental groups.

Results: Different metastatic sites which had been identified both by MicroCT and pathological sections appeared in each group of the four experimental groups. By contrast, no metastasis was observed in the control group. The percentage of cancer metastasizing to axial skeleton was remarkably higher than the percentage of tumor metastasizing to the limb bone in each experimental group, which was consistent with the clinical regularity and characteristics of skeletal metastases with lung cancer. Thus, the model has been established triumphantly. However, there were no statistical differences in the average time consumed and skeletal metastatic rate among the four experimental groups.

Conclusions: The disruption in the bone can be clearly detected by MicroCT, which is benefit to supervise the osseous metastasis. We successfully developed the nude mice bone metastasis model of lung adenocarcinoma, which will pave the way for exploring novel prevention and therapy strategies clinically. The four cell lines varied in invasion and migration abilities in vitro, but there was no statistical difference in the metastatic ability in vivo, and the reason need to be explored further in future.