2%超分子水杨酸对UVB所致小鼠光老化损伤的修复研究

Repair of 2%supramolecular salicylic acid on UVB induced photoaging in mice

目的 探究2%超分子水杨酸对中波紫外线(UVB)所致小鼠光老化损伤的修复作用。方法 选择30只6~8周龄昆明雌鼠,随机分为空白对照组、UVB组、UVB+2%超分子水杨酸组,各10只。空白对照组小鼠正常日光照射饲养, UVB组、UVB+2%超分子水杨酸组隔日用UVB照射1次,辐照12周,其中UVB+2%超分子水杨酸组小鼠在UVB照射后涂抹1次2%超分子水杨酸,非照射日每日涂抹1次;最后1次辐照结束后48 h观察三组小鼠皮肤组织形态变化情况,应用苏木精-伊红(HE)染色观察小鼠背部皮肤显微结构改变情况,测定表皮、真皮厚度,应用Masson染色观察真皮胶原纤维排列情况,测定胶原纤维含量,用免疫组化染色观察皮肤组织p21、p53表达情况。比较三组小鼠背部皮肤外形情况、皮肤显微结构改变情况及皮肤组织p21、p53阳性表达情况。结果 与空白对照组相比,UVB组小鼠皮肤粗糙,有深皱纹毛孔扩大,缺乏弹性,皮肤呈褐黄色斑,皮革样外观,镜下见毛细血管扩张,结痂,为典型光老化特征;UVB+2%超分子水杨酸组皮肤外观有隐约褐色斑,镜下见皮肤有散在、不规则褐色斑片,光老化症状较轻。三组背部皮肤损伤程度比较有明显差异性(P<0.05);UVB组背部皮肤损伤程度明显大于空白对照组和UVB+2%超分子水杨酸组,有明显差异性(P<0.05);空白对照组与UVB+2%超分子水杨酸组皮损程度比较也有明显差异性(P<0.05)。空白对照组表皮厚度、真皮厚度、真皮胶原纤维含量分别为(18.55±1.80)μm、(350.08±35.16)μm、(0.46±0.05)OD, UVB组分别为(79.68±21.37)μm、(611.62±16.37)μm、(0.15±0.30)OD, UVB+2%超分子水杨酸组分别为(60.99±11.49)μm、(467.94±20.71)μm、(0.32±0.03)OD。三组表皮厚度、真皮厚度及真皮胶原纤维含量比较有明显差异性(P<0.05);UVB+2%超分子水杨酸组和UVB组表皮厚度、真皮厚度明显多于空白对照组,真皮胶原纤维含量显著少于空白对照组,有明显差异性(P<0.05);UVB+2%超分子水杨酸组表皮厚度、真皮厚度明显少于UVB组,真皮胶原纤维含量多于UVB组,有明显差异性(P<0.05)。免疫组化显示空白对照组未见有p21、p53阳性表达。UVB+2%超分子水杨酸组皮肤组织p21、p53阳性表达率分别为30.00%、10.00%,低于UVB组的80.00%、60.00%,有明显差异性(P<0.05)。结论 2%超分子水杨酸对UVB所致小鼠光老化皮肤有修护保护作用,其机制与抑制凋亡相关基因p21、p53表达有关。

Objective To explore the repair of 2%supramolecular salicylic acid on ultraviolet B(UVB)induced photoaging in mice.Methods 30 Kunming female rats aged 6-8 weeks were selected and randomly divided into a blank control group,a UVB group,and a UVB+2%supramolecular salicylic acid group,each with 10 rats.The blank control group was fed under normal sunlight irradiation,the UVB group and the UVB+2%supramolecular salicylic acid group were irradiated with UVB once every other day for 12 weeks,in which the UVB+2%supramolecular salicylic acid group was applied with 2%supramolecular salicylic acid once after irradiation and once daily on non irradiation days.48 h after the end of the last irradiation,the morphological changes of the skin tissue of each group of mice were observed,hematoxylin-eosin(HE)staining was used to observe the structural changes of the dorsal skin,and measure the thickness of the epidermis and dermis.Masson staining was used to observe the arrangement of collagen fibers in the dermis,and measure the content of collagen fibers;immunohistochemical staining was used to observe the expression of p21 and p53 in the skin tissue.The dorsal skin appearance,skin microstructural changes and positive expression of p21 and p53 in skin tissues of three groups of mice were compared.Results Compared with the blank control group,the skin of mice in the UVB group was rough,with deep wrinkles,enlarged pores,and lack of elasticity;the skin presents brown yellow spots,with a leather like appearance.Microscopically,capillary dilation and crusting are seen,which were typical characteristics of photoaging.However,the skin of mice in the UVB+2%supramolecular salicylic acid group had faint brown spots,and under microscope,there were scattered and irregular brown patches on the skin,with less photoaging symptoms.There was significant difference in the degree of dorsal skin injury among the three groups(P<0.05).The degree of dorsal skin injury in UVB group was obviously greater than that of blank control group and UVB+2%supramolecular salicylic acid group,and there was a significant difference(P<0.05).There was also significant difference in degree of skin lesion between the blank control group and UVB+2%supramolecular salicylic acid group(P<0.05).The epidermal thickness,dermal thickness and dermal collagen fiber content of the blank control group were(18.55±1.80)μm,(350.08±35.16)μm and(0.46±0.05)OD,those of the UVB group were(79.68±21.37)μm,(611.62±16.37)μm and(0.15±0.30)OD,and those of UVB+2%supramolecular salicylic acid group were(60.99±11.49)μm,(467.94±20.71)μm and(0.32±0.03)OD.There was significant difference in epidermal thickness,dermal thickness and dermal collagen fiber content among the three groups(P<0.05).The epidermal thickness and dermal thickness in the VB+2%supramolecular salicylic acid group and UVB group were obviously more than those in the blank control group;the dermal collagen fiber content was significant less than that in the blank control group,and there was a significant difference(P<0.05).The epidermal thickness and dermal thickness in the VB+2%supramolecular salicylic acid group were obviously less than that in UVB group,and the dermal collagen fiber content was more than that in UVB group,and there was a significant difference(P<0.05).Immunohistochemistry showed no positive expression of p21 and p53 in the blank control group.The positive expression rates of p21 and p53 in UVB+2%supramolecular salicylic acid group were 30.00%and 10.00%,which were lower than 80.00%and 60.00%in UVB group,and there was a significant difference(P<0.05).Conclusion 2%supramolecular salicylic acid has a repairing and protective effect on UVB induced photoaging skin in mice,and its mechanism is related to inhibiting the expression of apoptosis related genes p21 and p53.