[Effect of progesterone on the pathogenesis and development of hemangioma in nude mice]

To explore the role of progesterone in the pathogenesis and development of hemangioma in nude mice.
 Methods: The hemangioma model was established. Progesterone was injected intramuscularly at different doses (0.2, 0.4, and 0.8 mg/d) for one week. Camellia oil (0.4 mL/d) was injected intramuscularly as control. The size of hemangioma was observed dynamically. The subcutaneous implants were harvested on the 14th and 28th days. The expression of vascular endothelial growth factor in the tumor tissues were evaluated using immunohistochemistry and microvessel density (MVD) was counted under the microscope.
 Results: On the 14th day, the expression of vascular endothelial growth factor (P<0.01 and P<0.05, respectively) was higher, the volume of tumors (All P<0.01) and MVD (All P<0.01) were greater in the high-dose progesterone group than those in the control and low-dose progesterone group. On the 28th day, there was no significant difference in the volume of tumors among 4 groups (P>0.05). The expression of vascular endothelial growth factor (P<0.01) was lower, and MVD (All P<0.05) were less in the middle-dose and high-dose progesterone group than those in the control and low-dose progesterone group.
 Conclusion: Progesterone promotes angiogenesis via upregulation of vascular endothelial growth factor expression, promotion of hemangiomas proliferation, suggesting that excessive progesterone supplementation may be one of the initial factors for early hemangioma formation.