氧化应激所致的人皮肤成纤维细胞衰老中β-连环蛋白的表达研究

目的 观察β-连环蛋白在氧化应激所致的人皮肤成纤维细胞衰老中的变化,探讨其在应激诱导的皮肤衰老中可能的作用.方法 从儿童包皮分离培养原代成纤维细胞,H2O2:处理第2～4代人皮肤成纤维细胞,显微镜观察其形态学改变,β-半乳糖苷酶细胞衰老试剂盒检测β-半乳糖苷酶活性,RT-PCR、Western印迹检测β连环蛋白mRNA和蛋白表达水平.结果 150 μmol/L H2O2:处理2 h后可以诱导人皮肤成纤维细胞衰老.在应激诱导的衰老(SIPS)细胞中β-半乳糖苷酶阳性率达到(37.67±1.53)%.而对照细胞中只有(2.97±0.25)%,两组差异有统计学意义(P<0.01).RT-PCR 结果显示,在对照细胞组β连环蛋白/GAPDH mRNA比值为0.59±0.04,SIPS细胞组为0.29±0.30,对照细胞组明显高于SIPS细胞组,两组差异有统计学意义(t=10.06,P<0.01).Western印迹结果显示,对照细胞组β连环蛋白/GAPDH蛋白比值为0.62±0.03,SIPS细胞组为0.31±0.01,对照细胞组明显高于SIPS细胞组,两组差异有统计学意义(t=14.97,P<0.0).结论 150 μmol/L H2O2:处理2 h可以诱导人皮肤成纤维细胞发生衰老改变,SIPS细胞中β连环蛋白表达水平明显降低,初步推测β连环蛋白可能是调控皮肤衰老的重要靶基因.

Abstract：

Objective To observe the changes of β-catenin expression in human skin fibroblasts (HSFs) after induced by oxidative stress, and to explore its possible roles in oxidative stress-induced premature senescence (SIPS) of HSFs. Methods Fibroblasts were isolated from the foreskin of a child and subjected to a primary culture. The fibroblasts of second to fourth passage were treated with various concentrations of H2O2 for 2 hours to establish an optimized model of stress-induced premature senescence, β-galactosidase assay kit was used to detect the activity of β-galactosidase in H2O2rinduced HSFs, RT-PCR and Western blot to measure the mRNA and protein expressions of β-catenin in control and senescent HSFs. Results Premature senescence of HSFs could be induced by the treatment with H2O2 of 150 μmol/L for 2 hours. The proportion of β-galactosidase-positive cells was (2.97 ± 0.25)% in control HSFs and (37.67 ± 1.53)% in senescent HSFs (P< 0.01). A significant increase was observed in the β-catenin/GAPDH protein ratio and β-catenin/GAPDH mRNA ratio in control HSFs compared with the senescent HSFs (0.62 ± 0.03 vs. 0.31 ± 0.01, t = 14.97, P < 0.01; 0.59 ± 0.04 vs. 0.29 ± 0.30, t = 10.06, P < 0.01). Conclusions The two-hour treatment with H2O2 of 150 μmol/L could induce the premature senescence of HSFs, and there is a notable decrease in the expression of β-catenin in prematurely senescent HSFs induced by oxidative stress, implying that β-catenin is an important target gene for the regulation of skin aging.