OBJECTIVETo investigate the therapeutic mechanism of Bleomycin A5 on infancy hemangioma.

METHODSAfter intralesional injection of Bleomycin A5 into the tumor of animal model of infancy hemangioma, the variation of tumor form was and the variation of tumor structure were observed using light microscope and electron microscope, the variation of tumor gene expression spectra was also tested by DNA microarray technique.

RESULTSAfter treatment, the tumor gradually shrunk, hardened, disappeared one month later. The tumor lost appearance of infancy hemangioma and replaced by lamellar collagen fibers and cellular nucleus scattered in the fibers, and almost all cells were necrotic and dissolved. Under electron microscope, only large stretches of dissolved cell could be seen without intact cells and blood vessels, but apoptotic cells and bodies could also be found. The results of DNA microarray analysis showed that 9 genes associated with apoptosis (murine double minute 2, heat-labile enterotoxin B subunit, lymphotoxin B receptor, tumor necrosis factor ligand superfamily 7, tumor necrosis factor receptor superfamily 21, tumor necrosis factor receptor superfamily 1A, myeloid cell leukemia-1, caspase3), 13 genes associated with cell proliferation and cell cycle (cell division cycle27, cell division cycle37, CDC28 protein kinase 1B, cycling B1, cullin 2, cullin 3, cullin 4A, growth arrest and DNA damage-inducible 45A, meiotic recombination 11 homolog B, forkhead box M1, minichromosome maintenance 7, antigen identified by monoclonal antibody ki 67, proliferating cell nuclear antigen), and 11 genes associated with cellular stress and toxic reaction (glutathione peroxidase 1, metallothioneins, superoxide dismutase-1, heat shock protein A1A, heat shock protein A2, heat shock protein A4, heat shock protein A5, heat shock protein 9B, heat shock protein CA, macrophage migration inhibitory factor, plasminogen activator inhibitor)were up or down regulated more than 2 folds in tumors treated with Bleomycin A5 compared with controls.

CONCLUSIONSThe therapeutic effect of Bleomycin A5 on infancy hemangioma is the synthetic results of multiple factors. Bleomycin A5 could not only induce apoptosis and inhibit cell proliferation, but also depressed the ability of cell stress and toxic reaction.