RESUMO
<p><b>OBJECTIVE</b>To establish a model bearing human lung cancer xenograft with bone metastasis in mice with normal immune function.</p><p><b>METHODS</b>Forty female C57BL/6J mice were randomly allocated into 4 equal groups, including a control group and 3 immunosuppression groups treated with low, moderate, and high doses of dexamethasone (50, 100, and 150 mg, respectively). Four days after immune suppression, the mice were subjected to percutaneous injection of1.0×10(9) L(-1) A549 cells into the tibial plateau, and the bone defects were assessed radiographically 28 days after modeling. HE staining and immunohistochemical staining were used to examine the tumor tissues and bone tissue damages.</p><p><b>RESULTS</b>In each of the 4 groups one mouse died during tumor cell injection. Only 1 mouse showed tumor formation in low-dose immunosuppression group, as compared to 7 and 4 in moderate- and high-dose immunosuppression groups. X-ray and microCT scan showed significant tibial bone destruction in moderate- and high-dose groups. The moderate- and high-dose groups showed similar ALP activities but both were significantly higher than those in the other two groups (P<0.05).</p><p><b>CONCLUSION</b>Immunosuppression with a moderate dose of dexamethasone results in longer survival time of the human lung cancer xenograft-bearing model mice as well as a higher tumor formation rate.</p>
