The Protective Effects of Long‐Term Oral Administration of Marine Collagen Hydrolysate from Chum Salmon on Collagen Matrix Homeostasis in the Chronological Aged Skin of Sprague‐Dawley Male Rats

<jats:p><jats:bold>Abstract: </jats:bold> To investigate the long‐term effects of marine collagen hydrolysate (MCH) from Chum Salmon skin on the aberrant collagen matrix homeostasis in chronological aged skin, Sprague‐Dawley male rats of 4‐wk‐old were orally administrated with MCH at the diet concentrations of 2.25% and 4.5% for 24 mo. Histological and biochemical analysis revealed that MCH had the potential to inhibit the collagen loss and collagen fragmentation in chronological aged skin. Based on immunohistochemistry and western blot analysis, collagen type I and III protein expression levels in MCH‐treated groups significantly increased as compared with the aged control group. Furthermore, quantitative real‐time polymerase chain reaction and western blot analysis showed MCH was able to increase the expressions of procollagen type I and III mRNA (COL1A2 and COL3A1) through activating Smad signaling pathway with up‐regulated TGF‐βRII (TβRII) expression level. Meanwhile, MCH was shown to inhibit the age‐related increased collagen degradation through attenuating MMP‐1 expression and increasing tissue inhibitor of metalloproteinases‐1 expression in a dose‐dependent manner. Moreover, MCH could alleviate the oxidative stress in chronological aged skin, which was revealed from the data of superoxide dismutase activity and the thiobarbituric acid reactive substances level in skin homogenates. Therefore, MCH was demonstrated to have the protective effects on chronological skin aging due to the influence on collagen matrix homeostasis. And the antioxidative property of MCH might play an important role in the process.</jats:p>