In vitro effects of propranolol and isoproterenol on the expression of beta-2 adrenergic receptor on infantile hemangioma endothelial cells

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 expression 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 expression 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 expression of beta-2 adrenergic receptor compared with the blank control group 1 (all P < 0.05) . However, the expression 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 expression of beta-2 adrenergic receptor on the surface of vascular endothelial cells, while isoproterenol can up-regulate its expression. Key words: Hemangioma; Infant; Endothelial cells; Propranolol; Isoproterenol; Receptors, adre-nergic, beta-2