Abstract: Objective To study the effects of hypoxia-inducible factor (HIF-1α) and apoptosis of the residual tumor cells in nude mice after treatment by high- intensity focused ultrasound (HIFU).Methods Human HCC implantation was established in 30 nude mice. CZF-Ⅱ HIFU therapeutic apparatus were used for treatment .Nude mice were randomly divided into control group and treatment group (included 1d group, 3d group, 5d group, 1w group,and 2w group). Pathological changes were observed with HE staining;Cell apoptosis were detected by DNA agarose gel electrophoresis and terminal deoxynucleotidyltransferase-mediated Dutp nick end-labeling (TUNEL) assay; SP immunohistochemistry was used to detect HIF-1α protein;Western blot and Real-time quantitative PCR were used to detect HIF-1α, P53 protein and mRNA expression levels. Results HE showed that there were residual tumor cells and large necrotic areas after treatment. Compared with other groups, the apoptosis index in 3d group was significantly higher (P <0.05),in the 5d group,1w group,2w group gradually decreased. Immunohistochemistry showed that the expression of HIF-1α, P53 protein was different in each group. Compared with other groups,Western blot and RT-PCR showed an increase of HIF-1α, P53 protein and mRNA levels in groups after treatment of 1 to 3 days, and peaked in 3d group(P <0.05). Conclusion HIFU treatment can induce consistent apoptosis in residual tumor, which may be related with disordered expression of HIF-1α and P53.

Key words: liver neoplasms、hypoxia-inducible factor、apoptosis