L-theanine alleviates muscle oxidative damage by improving mitochondrial function, maintaining calcium homeostasis,...

Oxidative stress represents a critical driver of impaired muscle integrity and compromised meat quality. This study investigates the protective effects and underlying mechanisms of l-theanine against oxidative stress-induced muscle damage. Our results DEMONSTRATED that diquat exposure triggered significant histopathological lesions, oxidative stress (elevated reactive oxygen species and malondialdehyde, decreased muscle antioxidant capacity), mitochondrial dysfunction (reduced adenosine triphosphate levels, mitochondrial membrane potential and gene expression related to mitochondrial biogenesis and function), calcium dyshomeostasis (cytosolic and mitochondrial Ca²⁺ overload), iron accumulation (increased free Fe²⁺), increased acyl-CoA synthetase long chain family member 4 expression and decreased glutathione peroxidase 4 expression. l-theanine pretreatment effectively reversed these pathological alterations. Collectively, l-theanine alleviated oxidative stress-induced muscle damage by enhancing antioxidant capacity, improving mitochondrial function, maintaining calcium homeostasis, and inhibiting ferroptosis. These findings provide a novel theoretical foundation for developing l-theanine-based nutritional strategies to enhance muscle health.