摘要目的 探讨不同剂量紫外线对光化性角化病(AK)与正常皮肤组织中增殖与凋亡、及p53、基质金属蛋白酶(MMP)2和MMP9表达的影响.方法 AK与正常皮肤组织分别分为4个组,对照组(照射剂量为0 J/cm2)、5 J/cm2组、10 J/cm2组、20J/cm2组.每块组织连续照射4d,继续培养24 h后取材.TUNEL检测细胞凋亡、Ki-67检测细胞增殖情况,定量PCR及免疫组化法检测p53、MMP2及MMP9表达.结果 紫外线照射后,与对照组相比,凋亡细胞百分比在正常皮肤组织10、20J/cm2组(46.8±2.1,56.7±2.4)增加,在AK 20 J/cm2(43.5±1.5)组增加,正常皮肤组织10、20J/cm2组比AK同剂量组增加(P＜0.05);Ki-67阳性细胞百分比在正常皮肤组织20J/cm2组(3.34±0.76)表达减少(P＜0.05),在AK中无明显变化(P＞ 0.05);p53 mRNA(5 J/cm2:1.106±0.025;10 J/cm2:1.259±0.045;20 J/cm2:1.425±0.053)及蛋白(10J/cm2:0.1169±0.0032;20J/cm2:0.1454±0.0047)在正常皮肤组织中表达增加,在AK中,mRNA(10 J/cm2:0.611±0.050;20J/cm2:0.578±0.070)及蛋白(20J/cm2:0.0404±0.0027)表达减少(P＜0.05);正常皮肤组织中MMP2 mRNA及蛋白(10J/cm2:1.086±0.013,0.0843±0.0024;20 J/cm2:1.417±0.036,0.1236±0.0042)、MMP9 mRNA及蛋白(20J/cm2:1.395±0.026,0.3065±0.0162)表达增加,AK中MMP2 mRNA及蛋白(20J/cm2:1.296±0.028,0.0744±0.0032)、MMP9mRNA及蛋白(10J/cm2:1.298±0.035,0.0992±0.0053;20J/cm2:1.286±0.032,0.1010±0.0063)表达增加(P＜0.05).结论 紫外线促进AK进展可能与其下调p53表达,上调MMP2和MMP9有关.

abstractsObjective To estimate the effect of different doses of ultraviolet (UV) radiation on the proliferation of and apoptosis in kertatinocytes,as well as on the expression of p53,matrix metalloproteinase-2 (MMP2) and-9 (MMP9) in actinic keratosis (AK) lesions and normal human skin.Methods Tissue specimens were obtained from the lesions of 20 patients with AK and sun-exposed normal skin of 20 healthy human subjects,and subjected to an air-exposed culture.Each of the specimens was divided into 4 areas to remain untreated (control area) or be irradiated with UV of 5,10 and 20 J/cm2 (irradiated areas) for 4 consecutive days.After another 24-hour culture,the tissue cultures were collected followed by the evaluation of apoptosis in and proliferation of keratinocytes by using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and Ki-67 staining,and determination of mRNA and protein expressions of p53,MMP2 and MMP9 by using real time PCR and immunohistochemistry respectively.Results A statistical increase was observed in the percentage of apoptotic cells in the normal skin irradiated with UV of 10 and 20 J/cm2 (46.8％ ± 2.1％ and 56.7％± 2.4％,both P ＜ 0.05) and in the AK lesions irradiated with UV of 20 J/cm2 (43.5％ ± 1.5％,P ＜ 0.05)compared with the corresponding unirradiated tissues.The normal skin showed a higher percentage of apoptotic cells than the lesional skin after irradiation with UV of 10 and 20 J/cm2 (both P ＜ 0.05).The percentage of Ki67-positive cells was significantly decreased in the normal skin after irradiation with UV of 20 J/cm2 (3.34％ ±0.76％,P ＜ 0.05),but experienced no statistical changes in the lesional skin after different doses of UV irradiation (all P ＞ 0.05).There was a statistical elevation in the expression of p53 mRNA (5 J/cm2:1.106 ± 0.025,10 J/cm2: 1.259 ± 0.045,20 J/cm2:1.425 ± 0.053,all P ＜ 0.05) and protein(10 J/cm2:0.1169 ± 0.0032,20 J/cm2:0.1454 ± 0.0047,both P＜ 0.05) in the normal skin,but a statistical reduction in the expression of p53 mRNA(10 J/cm2.0.611 ± 0.050,20 J/cm2:0.578 ± 0.070,both P ＜ 0.05) and protein (20 J/cm2:0.0404 ± 0.0027,P＜ 0.05) in the lesional skin after irradiation compared with the corresponding unirradiated skin tissues.Further more,a statistical increment was observed in MMP2 mRNA and protein expression in normal skin irradiated with UV of 10 J/cm2 (1.086 ± 0.013,0.0843 ± 0.0024,respectively,both P ＜ 0.05) and 20 J/cm2 (1.417 ± 0.036,0.1236 ±0.0042,respectively,both P ＜ 0.05) and in lesional skin irradiated with UV of 20 J/cm2 (1.296 ± 0.028,0.0744± 0.0032,respectively,both P ＜ 0.05),as well as in MMP9 mRNA and protein expression in normal skin irradiated with UV of 20 J/cm2 (1.395 ± 0.026,0.3065 ± 0.0162,respectively,both P ＜ 0.05) and in lesional skin irradiated with UV of 10 J/cm2 (1.298 ± 0.035,0.0992 ± 0.0053,respectively,both P ＜ 0.05) and 20 J/cm2(1.286 ± 0.032,0.1010 ± 0.0063,respectively,both P ＜ 0.05) compared with the corresponding unirradiated tissues.Conclusion Ultraviolet may accelerate the progression of AK by down-regulating p53 expression but up-regulating MMP2 and MMP9 expression.