Abstract: Zhu Yalin, Ma Long, Paride Abliz Department of Dermatology, First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, China Corresponding author: Paride Abliz, Email: palidae@aliyun.com 【Abstract】 Objective To explore the role of beta-2 adrenergic receptor in the pathogenesis of infantile hemangioma. Methods In vitro cultured infantile hemangioma endothelial cells were divided into propranolol and isoproterenol groups. The propranolol groups were further classified into 5 groups to be treated with propranolol solutions at concentrations of 10, 15, 20 μg/ml, EGM-2 medium （blank control group 1）, and EGM-2 medium containing 0.16% DMSO （DMSO group） respectively, while the isoproterenol groups were classified into 4 groups to be treated with isoproterenol solutions at concentrations of 5, 10, 20 μg/ml and EGM-2 medium （blank control group 2） respectively. After 24- and 48-hour treatment, enzyme-linked immunosorbent assay （ELISA） was performed to measure the of beta-2 adrenergic receptor in cell culture supernatants in the above groups. Results After 24-hour treatment, 15-μg/ml and 20-μg/ml propranolol groups showed significantly decreased of beta-2 adrenergic receptor compared with blank control group 1 and DMSO group （all P < 0.05）. After 48-hour treatment, all the propranolol groups showed significantly decreased of beta-2 adrenergic receptor compared with the blank control group 1（all P < 0.05）. However, the of beta-2 adrenergic receptor was significantly higher in the 10- and 20-μg/ml isoproterenol groups than in the blank control group 2 after 24-hour treatment （all P < 0.05）, and higher in the 20-μg/ml isoproterenol group than in the blank control group 2 after 48-hour treatment （P < 0.05）. Conclusion Propranolol can down-regulate the of beta-2 adrenergic receptor on the surface of vascular endothelial cells, while isoproterenol can up-regulate its .