Protective effect of selenomethionine against ultraviolet B-induced oxidative damage to a human keratinocyte cell line HaCaT / 中华皮肤科杂志

ABSTRACT

Objective To evaluate the effect of selenomethionine (Se-Met) against ultraviolet B (UVB)-induced oxidative damage to human HaCaT keratinocytes,and to explore its possible mechanisms.Methods Cultured HaCaT cells were divided into several groupsnormal control group receiving no treatment,Se-Met groups treated with Se-Met at concentrations of 1,10,50,100,200 nmol/L and 1 μmol/L for 24 hours respectively,UVB groups irradiated with UVB of 30,60 and 90 mJ/cm2 respectively,Se-Met + UVB groups treated with Se-Met at concentrations of 1,10,50,100,200 nmol/L and 1 μmol/L for 24 hours firstly,then irradiated with UVB of 30,60 and 90 mJ/cm2 respectively.Subsequently,methyl thiazolyl tetrazolium (MTT) assay was performed to estimate cellular proliferative activity,flow cytometry to detect cell apoptosis,colorimetry to evaluate superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and to determine malondialdehyde (MDA) levels.Statistical analysis was carried out by using factorial design analysis of variance (ANOVA),one-way ANOVA and least significant difference (LSD) test.Results Factorial design ANOVA showed that UVB radiation had an inhibitory effect on the proliferative activity of HaCaT cells (F =128.04,P ＜ 0.05),which significantly decreased along with the increase of UVB doses,with significant differences between the three UVB groups (P ＜ 0.05).Se-Met pretreatment also affected cellular proliferative activity (F =5.95,P ＜ 0.05),which was significantly increased in Se-Met (10 nmol/L-1 μmol/L) + UVB groups compared with the UVB groups at corresponding doses (all P ＜ 0.05).There was no significant interaction effect on cellular proliferative activity between UVB radiation and Se-Met pretreatment (F =1.65,P ＞ 0.05).The apoptosis rate of HaCaT cells in the 30-mJ/cm2 UVB group was 31.9％ ± 2.67％,significantly higher than that in the normal control group (4.1％ ± 0.67％,P＜ 0.05) and in the 10-,50-,100-,200-nmol/L and 1-μmol/L Se-Met + 30-mJ/cm2 UVB groups (21.9％ ± 3.72％,17.2％ ± 1.67％,4.6％ ±-0.85％,7.5％ ± 1.86％ and 13.5％ ± 1.95％ respectively,all P ＜ 0.05).Similarly,SOD and GSH-Px activities were significantly weaker (both P ＜ 0.05),while MDA levels were higher (all P ＜ 0.05) in the 30-mJ/cm2 UVB group than in the normal control group;however,there was a significant increase in SOD and GSH-Px activities but a decrease in MDA levels in the Se-Met (10 nmol/L-1 μmol/L) + 30-mJ/cm2 UVB groups compared with the 30-mJ/cm2 UVB group (all P ＜ 0.05).Conclusions Se-Met can reduce UVB-induced oxidative damage to HaCaT cells,likely by enhancing antioxidase activity and decreasing oxygen radicals.