Berberine exerts an anti-inflammatory role in ocular Behcet's disease

Behcet's disease is a multi-system inflammatory disorder, and ocular Behcet's disease (OBD) is one of the most common causes of uveitis in China. A number of studies have indicated that Th17 cells, a subset of interleukin-17 (IL-17)-producing CD4(+) T-helper cells, serve important roles in the pathogenesis of OBD. Berberine (BBR) is an isoquinoline derivative alkaloid isolated from Chinese herbs, and has been used traditionally for the treatment of gastrointestinal disorders. The aim of the present study was to investigate the effect of BBR on Th17 cell proliferation and cytokine secretion, and the expression and activation of the signal transducer and activator of transcription 3 (STAT3) transcription factor in OBD in vitro. Blood samples were obtained from healthy controls and patients with active ocular Behcet's disease. Peripheral blood mononuclear cells (PBMCs) or CD4(+) T cells were cultured for three days with or without BBR and in the presence of anti-CD3 and anti-CD28 antibodies. IL-17 expression in cell sample supernatants was determined by enzyme-linked immunosorbent assay, and cell viability was measured using the Cell Counting kit-8 assay. The number of CD4(+)IL-17(+) cells and the expression level of phosphorylated (p)-STAT3 in CD4(+) T cells was determined using flow cytometry analysis. The expression of IL-17 was increased in patients with active OBD following the activation of PBMCs and CD4(+) T cells with anti-CD3 and anti-CD28 antibodies when compared with healthy controls. However, no significant difference in cell viability following exposure to BBR was observed in PBMCs derived from healthy controls or patients with OBD. Following incubation with BBR, the expression of IL-17 was reduced and the number of CD4(+)IL-17(+) cells was decreased in patients with active OBD and healthy controls. Furthermore, the expression of p-STAT3 was significantly decreased in the presence of BBR in healthy controls. In conclusion, the results of the present study demonstrate that BBR may suppress the Th17 response in patients with OBD by reducing STAT3 phosphorylation. BBR may be a potential therapeutic agent for the treatment of OBD.