Chitosan-Based Taurine Nanoparticles Alleviate Dexamethasone-Induced Pulmonary–Thyroid Axis Dysfunction via Redox–Inflammatory Signaling Modulation in Rats

Dexamethasone induces systemic toxicity, including oxidative stress, inflammation, hematological disturbances, and organ damage, particularly in the lungs and thyroid. Taurine exhibits antioxidant and anti-inflammatory properties, but poor bioavailability limits its efficacy. Nanoparticle delivery may enhance stability and tissue targeting. This study aimed to evaluate the protective effects of taurine-loaded chitosan nanoparticles (Tau–CS NPs) against dexamethasone-induced tissue injury in rats. Forty-eight male Wistar rats were allocated into control, DEXA, DEXA + silymarin, DEXA + taurine, and DEXA + Tau–CS NPs groups. Tau–CS NPs were characterized by TEM, UV–vis, FTIR, encapsulation efficiency, and drug loading. Hematology, oxidative stress markers (CAT, SOD, GSH, MDA), thyroid hormones (T3, T4, TSH, calcitonin), protein profile, lung and thyroid histopathology, and MPO expression were assessed. Tau–CS NPs showed uniform spherical morphology (11–60 nm), high encapsulation (98.2%), and substantial loading (50.36%). Dexamethasone caused hematological, oxidative, thyroidal, and histological disturbances. Tau–CS NPs markedly restored hematological indices, antioxidant defenses, thyroid function, protein profile, and tissue architecture, outperforming free taurine and silymarin. MPO expression was significantly reduced, indicating decreased inflammation. Taurine nanoparticles effectively mitigate dexamethasone-induced systemic and organ-specific toxicity, offering improved bioavailability and targeted delivery, highlighting their therapeutic potential.