The Role of miR-144/Nrf2 Pathway in Muscle Oxidative Stress Induced by Oxidized Fish Oil in Megalobrama amblycephala, with an Emphasis on Protein Oxidation

This study investigated the role of <i>miR-144</i> in mitigating oxidized fish oil (OFO)-induced muscle oxidative stress and quality deterioration in <i>Megalobrama amblycephala</i>. The feeding trial was conducted for 5 weeks, and four experimental diets were formulated, namely NC (fresh fish oil), OF (OFO), OF + ago (OFO and <i>miR-144</i> agomir), and OF + anta (OFO and <i>miR-144</i> antagomir). Histological results showed that OFO significantly reduced myofiber density (from 758.00 ± 13.69 to 636.57 ± 13.44 N/mm²) and decreased the percentage of myofibers with diameters > 50 μm (from 53.45% to 38.52%). OFO intake significantly increased the content of malondialdehyde (MDA), protein carbonyl (PC), advanced oxidation protein product (AOPP), and 3-nitrotyrosine (3-NT), and significantly decreased superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity in muscle. OFO treatment significantly up-regulated the expression of inflammatory factors (<i>NF-κB</i>, <i>TNF-α</i>, <i>HO-1</i>, and <i>IL-6</i>), significantly down-regulated <i>NQO1</i>. Moreover, OFO reduced muscle differentiation and maturation by down-regulating the expression of <i>MyoG</i>, <i>MYHC1</i>, and protein synthesis genes (<i>AKT3</i>, <i>TOR</i>, and <i>S6K1</i>), and up-regulating the expression of protein hydrolysis genes (<i>FoxO3a</i>, <i>MuRF1</i>, <i>HSP70</i>, <i>Beclin-1</i>, <i>P62</i>, and <i>ATG8</i>). Moreover, miR-144 agomir exacerbated OFO-induced muscle damage by suppressing <i>Nrf2</i>, whereas miR-144 antagomir mitigated these effects. Silencing miR-144 re-activates <i>Nrf2</i>, alleviating oxidative damage, enhancing protein deposition, and improving muscle quality. These findings suggest that targeting the miR-144/Nrf2 axis could counteract OFO-induced muscle deterioration.