A betaine-contained solution ameliorates cold ischemia reperfusion injury by suppressing ferroptosis in porcine kidney

• The present paper demonstrates the following: • Ferroptosis, a novel form of cell death characterized by iron accumulation and lipid peroxidation, plays a pivotal role in renal cold ischemia/reperfusion (I/R) injury during kidney transplantation. • Betaine in solution ameliorates cold ischemia/reperfusion injury by suppressing ferroptosis. • The modified MS solution exhibits a superior ability to preserve kidney function compared to the Hypertonic Citrate Adenine (HCA) solution, demonstrating similar efficacy to the UW solution. Intracellular iron-mediated lipid oxidative damage, referred to as ferroptosis, plays a crucial role in renal ischemia-reperfusion (I/R) injury. This study aims to investigate the effects of a betaine-contained organ preservation solution on renal ferroptosis using the normothermic machine perfusion (NMP) system. Healthy adult Bama miniature pigs were utilized in this study. Both kidneys were harvested and stored at 4°C using three organ preservation solutions: Hypertonic Citrate Adenine (HCA) solution, University of Wisconsin (UW) solution, and modified multiple-saccharide (MS2) solution, for a duration of 24 hours. The kidneys were subsequently divided into HCA, UW, and MS groups. The kidneys stored in cold for 2 hours were used as a control. All kidneys were reperfused using the NMP system for 2 hours. Biochemical indicators and ferroptosis-related markers, including iron levels, oxidative stress, and Acyl-CoA synthetase long-chain family member 4 (ACSL4), were measured. During the 2-hour NMP, prolonged cold storage and reperfusion significantly induced ferroptosis-mediated renal I/R injury, resulting in severe renal tubular damage. Notably, levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), ACSL4, and iron were significantly elevated in the HCA group compared to the control group (P<0.05), while these levels were significantly reduced in the UW and MS groups. Additionally, the MS group exhibited results similar to those of the UW group in preventing renal I/R injury. This study indicates that the betaine-containing MS solution attenuates ferroptosis-mediated renal cold I/R injury by inhibiting oxidative stress.