N-Acetylcysteine Attenuates Oxidative Stress and Preserves Red Blood Cell Quality During Whole Blood Storage

Whole blood (WB) storage induces biochemical and biomechanical alterations that may compromise red blood cell (RBC) quality. Since oxidative stress is a major driver of storage lesions, we investigated whether N-acetylcysteine (NAC) could attenuate these changes during refrigerated storage. WB from healthy donors was stored at 4 °C for 42 days with or without NAC, added either once at baseline or every 10 days. Plasma albumin proteoforms were assessed by liquid chromatography–mass spectrometry, free hemoglobin species by spectrophotometry, plasma proteomic changes by proximity extension assay, and RBC hemorheological properties by LORRCA analysis. Storage decreased reduced albumin (HSA-SH) and increased oxidized albumin (HSA-Cys), indicating plasma oxidation. Free oxyhemoglobin, deoxyhemoglobin, and methemoglobin increased, consistent with hemoglobin oxidation and hemolysis. Storage also induced plasma proteomic alterations and impaired RBC osmotic and deformability parameters. NAC preserved albumin redox status, limited free hemoglobin accumulation, and attenuated storage-induced proteomic changes. Moreover, NAC partially preserved RBC osmotic and rheological properties, particularly parameters related to osmotic fragility and hydration. No clear advantage of 20 mM over 10 mM NAC was observed. Overall, NAC attenuated oxidative and functional alterations associated with refrigerated whole blood storage, supporting further investigation of antioxidant supplementation as a strategy to mitigate storage lesions under ex vivo conditions.