The establishment of the hemangioma model in nude mouse

Abstract

Background/Purpose Hemangioma is one of the most common benign tumors in children. Most of them could regress spontaneously; however, the pathogenesis and triggering of regression are still unknown. Here, we introduce a new means in which the specimen of human hemangioma was transplanted into nude mice subcutaneously. At the same time, high dose of estradiol was administered to the experimental nude mice intramuscularly to promote implantation and proliferation of hemangioma endothelial cells. By this means, a credible animal model of human hemangioma was established. Further studies on pathogenesis and medical intervention of hemangioma could be carried on with this model. Methods The specimen of grafted hemangioma was taken from a 6-month-old girl, in whom the hemangioma grew rapidly, by surgery. The fresh estrogen receptor–positive strawberry hemangioma specimens were sliced and inoculated subcutaneously into 16 nude mice that were divided randomly into 2 groups, namely, group 1 (n = 8) with normal diet and group 2 (n = 8) with normal diet and 10 −7 mg estradiol administered intramuscularly every week additionally. The size of grafts was measured weekly. All of the experimental mice were killed at 90 days after graft. Hemangioma tissues were harvested and sliced into 4 to 5 μm sections. Living grafts were subjected to histopathologic examination and immunohistochemistry for CD34 and Ki-67. Results All of the sizes of hemangioma tissues in group 1 were diminished distinctly in 30 days. Thirteen samples of hemangioma were almost absorbed and disappeared completely in 90 days. The sizes of hemangioma in group 2 were larger than primary specimens. It was observed from the section of hemangioma that endothelial cells proliferate vividly and fresh capillary blood vessels grew up into the body of hemangioma. The mean positive cell rate of CD34 in group 2 was 48.49 ± 3.90 and the Ki-67 was 15.04 ± 2.44. The transplanted tumor cell retained the histologic characters of original tumor. Conclusion The capillary hemangioma model established in nude mice retains almost all the biologic character of original human hemangioma and could be widely used in further study on hemangioma.