Oral Intake of Collagen and Collagen Hydrolysate From <i>Takifugu bimaculatus</i> Attenuates Ultraviolet‐Induced Skin Photoaging in Mice

With the rapid emergence of pufferfish aquaculture and processing industries, fish skin is underutilized as a byproduct of processing, leading to resource waste. In this study, <i>Takifugu bimaculatus</i> skin collagen (TBSC) was extracted by acetic acid solubilization and its physicochemical properties were analyzed. The effects of TBSC and the TBSC hydrolysate (TBSCH) on ultraviolet (UV) irradiation-induced photoaging were investigated using a mouse model. The purity of TBSC was 90.02%. Electrophoresis and Fourier infrared spectroscopy characterization of TBSC showed that the type of collagen in TBSC was typical standard type I. The degree of hydrolysis was selected to optimize the hydrolysis conditions for TBSC. The papain enzyme dosage, temperature, pH, and hydrolysis duration of 51,000 U/g, 48.03°C, 5.35, and 4 h have been demonstrated to be the optimum hydrolysis conditions for TBSCH. Oral administration of either TBSC or TBSCH ameliorated UV-induced skin erythema and hyperkeratosis. TBSC and TBSCH treatment increased collagen content and had an inhibitory effect on matrix metalloproteinase (MMP)-2 and MMP-3 expression, whereas MMP-9 expression was significantly reversed only in the TBSCH-treated groups. The expression of the c-Jun protein was much lower in these groups, suggesting that TBSCH had a greater alleviating effect on collagen degradation and extracellular matrix breakdown. Therefore, it is proposed that TBSCH has the potential to be used as a nutricosmetic agent with protective attributes against UV-induced skin damage and concurrent collagen depletion.