The effect of puerarin against IL-1β-mediated leukostasis and apoptosis in retinal capillary endothelial cells (TR-iBRB2)

PURPOSE: Blood–retinal barrier (BRB) breakdown, the early hallmark of diabetic retinopathy (DR), is thought to depend on retinal inflammation and cell damage. The proinflammatory factor interleukin-1β (IL-1β) was demonstrated to cause inflammation as well as cell apoptosis during the process of BRB breakdown. This study extensively evaluated the protective effect of puerarin, a major active component extracted from the traditional herb Radix puerariae, against IL-1β-induced cell dysfunction in TR-iBRB2 cells, a retinal capillary endothelial cell line. METHODS: TR-iBRB2 cells were pretreated with IL-1β (10 ng/ml) for 24 h and then exposed to puerarin (0, 10, 25, and 50 μM) for another 24 h. Leukocyte endothelial adhesion was assessed through a cell-based assay using lymphoblastoid cells. Cell apoptosis was evaluated with flow cytometry, and the expression of adhesion molecules and apoptosis-related molecules was assessed with western blot analysis. RESULTS: Our data showed that puerarin attenuated IL-1β-mediated leukostasis and cell apoptosis in TR-iBRB2 cells. Furthermore, puerarin strikingly prevented IL-1β-induced molecular events of the upstream and downstream signaling pathways involved in this cellular process. CONCLUSIONS: These findings may significantly contribute to better understanding of the protective effect of puerarin, in particular for DR, as well as provide novel insights into the potential application of this compound in DR therapy.