Establishment and Imaging Studies of Human Lung Cancer-Associated Brain Metastasis Animal Models

Background: Lung cancer is one of the malignant tumors with fast increase in morbidity and mortality, and great threat to human health and life. Methods: Animal models (n = 5) were performed by injecting 1 x 10(6) A549 cells in 0.1 mL phosphate buffer saline into nude mice through the left ventricle. Body weight of animals was measured every 3 days, and changes in the appearance and behavior were observed. Brain magnetic resonance imaging of 5 animals were performed using T1, T1 enhancement and T2 scan at the 4th, 6th, and 7th weeks after injected with tumor cells. Animals (n = 5) were sacrificed after the last magnetic resonance scan, and brain slices of the animals were prepared to conduct hematoxylin-eosin staining. Results: At the 4th weeks after inoculation of tumor cells, there was no obvious change in the appearance and behavior of animals and there were no obvious tumor metastases in the brains from brain magnetic resonance scan. At the 6th weeks, body weight of all animals (n = 5), one of which appeared paralysis in hind limb, decreased obviously, and results from MR scans showed there were tumor metastases in the brains of all animals. Results from brain magnetic resonance scan images of one animal at 4th, 6th, and 7th weeks showed tumor metastases appeared in the animal's brain and gradually grew bigger. Result from hematoxylin-eosin staining of brain slices showed multiple tumor metastases, consistent with the results of magnetic resonance imaging. Conclusions: Human lung cancer-associated brain metastasis animal models was successfully established, and micro-magnetic resonance imaging is a sensitive, accurate and non-invasive method for the detection of lung cancer brain metastases in mice through this study.