目的研究表没食子儿茶素没食子酸酯(EGCG)对中波紫外线(UVB)慢性辐射诱导BALB/c小鼠皮肤TNF-αmRNA表达及p53蛋白表达水平的影响。方法EGCG局部外用于小鼠背部及耳部皮肤后给予不同强度的UVB辐射,每日1次,连续1个月,RT-PCR法检测不同处理条件下小鼠背部皮肤组织中TNF-αmRNA的表达水平,免疫组化法检测耳部皮肤组织中p53蛋白表达水平。结果经β-actin内参校正后,RT-PCR示不同剂量UVB慢性辐射后小鼠皮肤中TNF-αmRNA表达水平较对照组升高,但表达水平与UVB辐射强度间无明确的剂量依赖关系。UVB慢性辐射诱导小鼠皮肤p53蛋白表达,且表达水平与UVB辐射强度间呈剂量依赖关系。EGCG处理后可下调UVB辐射诱导的TNF-αmRNA水平及p53蛋白表达。结论UVB辐射能诱导小鼠皮肤TNF-αmRNA及p53蛋白表达,EGCG可干预UVB辐射诱导的上述作用。

Objective To investigate the effects of topical application of (-)-epigallocatechin-3-gallate (EGCG) on TNF-α mRNA and p53 protein expression levels in the skin of BALB/c mice irradiated by ultraviolet B (UVB). Methods BALB/c mice were pretreated with 30 mg/mL EGCG daily then irradiated with different dosages of UVB for consecutive 30 d. The skin samples were obtained after one month. TNF-α mRNA Expression was measured by RT-PCR and immunohistochemical method was used to detect p53 protein expression level. Results Compared with the control group, TNF-α mRNA expression in the skin of irradiated BALB/c mice was statistically increased after chronic UVB irradiation, but there was no definite dose-dependent effect. p53 Protein expression level in the skin of BALB/c mice irradiated by different dosages of UVB increased gradually and there was a dose-dependent effect. The pretreatment of EGCG could down regulate TNF-α mRNA and p53 protein expression levels induced by UVB irradiation. Conclusion TNF-α mRNA and p53 protein expression levels in BALB/c mouse skin are increased after UVB irradiation and topical application of EGCG can down-regulate TNF-α mRNA and p53 expression, which may play a major role in its photoprotection mechanism.

国家自然科学基金资助项目(编号30371294)