中文摘要：

本文研究了大马哈鱼皮明胶（SG）对光老化小鼠皮肤的保护机制。采用热提法制备了SG并对其分子量和氨基酸组成进行分析。ICR小鼠随机分成5组（每组10只）：正常组（NC）、模型组（MC）、维生素C组（PC）、SG低剂量组（SG-L）和SG高剂量组（SG-H）。本文分析了皮肤组织中总超氧化物歧化酶（T-SOD）、谷胱甘肽过氧化物酶（GSH-Px）和过氧化氢酶（CAT）的活力,丙二醛（MDA）和羟脯氨酸（HYP）的含量,并利用HE、Masson染色来评价SG对光老化皮肤的保护作用。结果表明,SG平均分子量在81.31 ku,甘氨酸约占其氨基酸总量的1/3,疏水性氨基酸占49.67%,不含有半胱氨酸和色氨酸。SG可以改善紫外线对皮肤中胶原纤维的损伤,与模型组相比,SG高剂量组可以显著提高T-SOD的活力（p〈0.05）、HYP含量（p〈0.01）、降低MDA含量（p〈0.05）,使CAT和GSH-Px平均活力分别提高23.70%和28.30%。SG对紫外线引起的皮肤光老化有保护作用。

英文摘要：

The protective mechanism of gelatin against ultraviolet irradiation-induced photoaging of skin was investigated in this study. Gelatin derived from pacific-salmon skin（SG） was extracted using hot water and the molecular weight and amino acid composition analyzed. Institute of Cancer Research（ICR） mice were randomly divided into five groups, with ten mice per group： normal group（NC）, model group（MC）, vitamin C group（PC）, low dose SG treatment group（SG-L）, and high dose SG treatment group（SG-H）. The activities of total superoxide dismutase（T-SOD）, glutathione peroxidase（GSH-Px）, and catalase（CAT） were measured in skin tissues, as were the levels of malondialdehyde（MDA） and hydroxyproline（HYP）. The protective effects of SG on photoaging were evaluated by haematoxylin and eosin staining and Masson＇s trichrome staining. The results indicated that the average molecular weight of SG was 81.31 Ku. Glycine accounted for approximately one-third of the total amino acids in SG, and 49.57% of amino acids were hydrophobic. Cysteine and tryptophan were not detected in SG. SG could protect collagen fibers against UV irradiation-induced photodamage. Compared with the control group, the SG-H group exhibited significantly enhanced activity of T-SOD（p 0.05）, increased levels of HYP（p 0.01）, and reduced levels of MDA（p 0.05）. In addition, average activities of CAT and GSH-Px increased by 23.70% and 28.30%, respectively, in the SG-H group. This study shows that SG can effectively protect mouse skin from UV irradiation-caused photodamage.