Serum albumin oxidation and inter-alpha-trypsin-inhibitor heavy chain-4 abundance correlates with the dystropathology in the rat model of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a fatal X‑linked genetic disease caused by the absence of functional dystrophin, resulting in muscle membrane fragility, chronic inflammation, and progressive muscle wasting. The lack of effective treatments is further compounded by the slow onset of measurable changes in clinical outcomes, such as muscle strength, which often take a year or longer to become evident. Blood‑based biomarkers that can predict treatment efficacy and monitor disease progression would significantly accelerate therapeutic development. We propose that oxidative modifications to proteins in blood, a consequence of muscle inflammation, could be used to monitor disease progression in DMD. Using the DMDmdx rat, a model with more severe dystropathology than the mouse model of dystrophy (mdx), we assessed inflammation and oxidative stress in muscle and blood across disease stages. DMDmdx rats aged 1.5–12 months showed sustained immune activation, as indicated by elevated circulating leukocytes and increased myeloperoxidase content in dystrophic muscle compared with wild type. Oxidative protein modifications, including carbonylation, tyrosine chlorination, and thiol oxidation, were significantly elevated in serum and tissues of dystrophic rats. Two proteins showed distinct disease‑associated oxidative changes: albumin, which exhibited consistently increased thiol oxidation across ages, and inter‑alpha trypsin inhibitor 4 (ITIH4), which showed elevated chlorination between 1.5–4.5 months. Notably, serum ITIH4 abundance correlated with markers of muscle inflammation and oxidative stress. These findings identify serum albumin thiol oxidation and serum ITIH4 abundance as promising blood‑based biomarkers for monitoring inflammation‑associated dystropathology in DMD.