Melatonin activates Nrf2 to inhibit ferroptosis and improves the survival of random skin flaps
LOUChenghao 1, 2, 3, LU Yingfeng 1, 2, 3, WANG Jian 1, 2, 3.
1.Department of Wound Repair, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, China; 2.Department of Hand Surgery and Peripheral
Neurosurgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, China; 3.School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou 325035, China
LOUChenghao,LU Yingfeng,WANG Jian.. Melatonin activates Nrf2 to inhibit ferroptosis and improves the survival of random skin flaps[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2023, 53(7): 526-531，539.
Abstract：Objective: To investigated whether melatonin (MLT) can promote the survival of random flaps ，by reducing ferroptosis in random flaps. Methods: Twenty male C57BL/6 mice aged 6-8 weeks were randomly divided as the control group and MLT group. The flap survival and hemodynamics after 3 and 7 days in both groups were observed. The flap tissue was taken to evaluate edema, and the effect of melatonin on the survival of random flaps and the regulation of ferroptosis was investigated by pathological staining, transmission electron microscope and immunoblotting. In order to explore the role of nuclear factor erythroid 2-related factor 2 (Nrf2) in the inhibition of ferroptosis by melatonin, 45 male C57BL/6 mice aged 6-8 weeks were randomly divided into control group, MLT group, and MLT+ml385 group. Morphological changes were observed and changes in relevant biochemical indicators were detected. Results: Distal flap necrosis occurred in all groups on day 3 and day 7. Compared with the control group, MLT group had the increased flap survival area (P<0.05) and flap blood perfusion (P<0.05). HE staining showed that MLT group had more small blood vessels in the flap, and Masson staining showed that fibres in the dermis were regularly arranged in MLT group. Immunohistochemical stainingshowed that MLT group had more CD34-positive vessels (P<0.05), reduced apoptosis-related proteins (P<0.05) and increased content of antioxidant protein (P<0.05), compared with the control group. Characteristic changes of ferroptosis in the flap tissue were observed by transmission electron microscopy. Tissue lipid peroxide detection, tissue iron content detection, glutathione level and western blot results showed that MLT group up-regulated GSH (P<0.05), decreased tissue iron accumulation (P<0.01), and reduced lipid oxidation level (P<0.05). After the combined use of ml385, the results of western blot showed that compared with the MLT group, Nrf2 (P<0.05),the antioxidant protein HO-1 (P<0.05), the anti-lipid peroxidation protein GPX4 (P<0.05), and the iron-binding protein light chain FTL (P<0.05) were down-regulated in the MLT+ml385 group. Conclusion: This study demonstrates that MLT treatment favors the survival of random skin flaps in mice. Ferroptosis is one of the factors affecting the survival of random skin flaps, and inhibition of ferroptosis can promote the survival of random skin flaps; MLT’s inhibition of ferroptosis depends on the activation of Nrf2 to improve antioxidant capacity, reducelipid peroxidation and promote iron metabolism.
