ObjectiveTo observe the effect of triamcinolone acetonide(TA) on activation and barrier function of human retinal pigment epithelium （RPE）.MethodsARPE-19 cells were cultured in 96well tissue culture plate. Four weeks later, TA with different concentration (0.02 and 0.05 mg/ml)was added to the cells and culture for 3 or 7 days. The activation of ARPE-19 cells was assessed by methyl thiazolyl tetrazolium (MTT). ARPE-19 cells were cultured on polyester microporous filters for 4 weeks, and the transepithelial resistance (TER) was recorded. TA (0.02 and 0.05 mg/ml) was added to the culture fluid respectively, and after cultured for 1 week TER was measured again. The RPE permeability was detected by enzymelinked immunosorbent assay (ELISA) with horse radish peroxidase as the tracer. ResultsIn the culture fluid with 002 mg/ml TA cultured for 3 or 7 days, the average survival rate of ARPE-19 cells was 93.70% and 90.63% respectively, without statistic difference compared with the control (P=0.147, 0.091). While in the 0.05 mg/ml TA group after cultured for the same duration, the activation of ARPE-19 cells decreased significantly compared with the control (with the average survival rate of 87.75% and 88.98%; P=0.025, 0.043). One week after cultured with TA, TER decreased significantly while permeability improved obviously in the 2 TA groups compared to the control (Plt;0.001; 0.001lt;Plt;0.05).ConclusionTA may decrease the activation of and destroy the barrier function of ARPE-19 cells. (Chin J Ocul Fundus Dis, 2005,21:237-239)