Objective:To investigate the protective effects of the natural medicinal monomer isopsoralen(ISR) with estrogenic activity against oxidative damage in human lens epithelial cells B3(HLE-B3) caused by hydrogen peroxide(H_2O_2) and to pursue the possible mitochondrial proteomic regularity of the protective effects.Methods: HLE-B3 cells were treated with H_2O_2(300μmol/L),β-estradiol(E_2:10~(-8) mol/L) and H_2O_2,ISR(10~(-5) mol/L) and H_2O_2,or left untreated.Altered expressions of all mitochondrial proteins were analyzed by protein array and surfaceenhanced laser desorption ionization time of flight mass spectrometry(SELDI-TOF-MS).The mass/charge(m/z) ratios of each peak were tested by the Kruskal-Wallis rank sum test,and the protein peak value of the m/z ratio for each treatment by pair comparison was analyzed with the Nemenyi test.Results:H_2O_2 up-regulated the expressions of two protein spots(with m/z of 6532 and 6809).E_2 mitigated the oxidative damage,and the expression of one protein spot(m/z 6532) was down-regulated.In contrast,ISR down-regulated both of protein spots(m/z 6532 and 6809).Conclusions:ISR could effectively inhibit H_2O_2-induced oxidative damage in HLE-B3 cells.The protein spot at m/z of 6532 might be the target spot of ISR against oxidative damage induced by H_2O_2. Objective: To investigate the protective effects of the natural medicinal monomer isopsoralen (ISR) with estrogenic activity against oxidative damage in human lens epithelial cells B3 (HLE-B3) caused by hydrogen peroxide (H_2O_2) and to pursue the possible mitochondrial proteomic regularity of the protective effects.Methods: HLE-B3 cells were treated with H_2O_2 (300μmol / L), β-estradiol (E_2: 10 -8 mol / L) and H_2O_2, ISR (10 ~ (-5) mol / L) and H_2O_2, or left untreated. Altered expressions of all mitochondrial proteins were analyzed by protein array and surface enhanced enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF-MS). Mass / charge (m / z) ratios of each peak were tested by the Kruskal-Wallis rank sum test, and the protein peak value of the m / z ratio for each treatment by pair comparison were analyzed with the Nemenyi test. Results: H 2 O 2 up-regulated the expressions of two protein spots (with m / z of 6532 and 6809) .E_2 mitigated the oxidative damage, and the expression of one p ISR could effectively inhibit H 2 O 2 -induced oxidative damage in HLE-B3 cells. (r / min) The protein spot at m / z of 6532 might be the target spot of ISR against oxidative damage induced by H_2O_2.