A new low molecular weight, MnII-containing scavenger of superoxide anion protects cardiac muscle cells from hypoxia/reoxygenation injury. (January 2015)

• Record Type: Journal Article
• Authors: Nistri, S.; Boccalini, G.; Bencini, A.; Becatti, M.; Valtancoli, B.; Conti, L.; Lucarini, L.; Bani, D.
• Is Part Of: Free radical research. Volume 49:Number 1(2015:Jan.)
• Page Start: 67
• Page End: 77
• Publication Date: 2015-01
• Subjects: Free radicals (Chemistry) -- Periodicals; Antioxidants -- Periodicals; Vitamin C -- Periodicals; Vitamin E -- Periodicals; 541.224
• Languages: English
• ISSNs: 1071-5762

Abstract

<abstract> <title>Abstract</title> <p>Reperfusion injury after oxygen starvation is a key pathogenic step in ischemic diseases. It mainly consists in oxidative stress, related to mitochondrial derangement and enhanced generation of reactive oxygen species (ROS), mainly superoxide anion (O<sub>2</sub><sup>2</sup>), and peroxynitrite by cells exposed to hypoxia. This <italic>in vitro</italic> study evaluates whether Mn<sup>II</sup>(4, 10-dimethyl-1, 4, 7, 10-tetraazacyclododecane-1, 7-diacetate).2H<sub>2</sub>O, or Mn<sup>II</sup>(Me<sub>2</sub>DO2A), a new low molecular weight, Mn<sup>II</sup>-containing O<sub>2</sub><sup></sup> scavenger, has a direct protective action on H9c2 rat cardiac muscle cells subjected to hypoxia and reoxygenation. Mn<sup>II</sup>(Me<sub>2</sub>DO2A) (1 and 10 μmol/l) was added to the culture medium at reoxygenation and maintained for 2 h. In parallel experiments, the inactive congener Zn<sup>II</sup>(Me<sub>2</sub>DO2A), in which Zn<sup>II</sup> replaced the functional Mn<sup>II</sup> center in the same organic scaffold, was used as negative control. Mn<sup>II</sup>(Me<sub>2</sub>DO2A) (10 μmol/l) significantly increased cardiac muscle cell viability (trypan blue assay), improved mitochondrial activity (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide test, membrane potential Δψ), reduced apoptosis (mitochondrial permeability transition pore opening, caspase-3, terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling assay), decreased intracellular ROS levels (2', 7'-dichlorodihydrofluorescein diacetate and MitoSOX assays), and decreased protein nitroxidation (nitrotyrosine [NT] expression) and DNA oxidation (8-hydroxy-deoxyguanosine levels). Of note, Zn<sup>II</sup>(Me<sub>2</sub>DO2A) had no protective effect. The mechanism of Mn<sup>II</sup>(Me<sub>2</sub>DO2A) relies on concentration-dependent removal of harmful O<sub>2</sub><sup></sup> generated at reoxygenation from dysfunctional mitochondria in hypoxia-induced cells, as indicated by the MitoSOX assay.</p> <p>This study suggests that Mn<sup>II</sup>(Me<sub>2</sub>DO2A) is a promising antioxidant drug capable of reducing O<sub>2</sub><sup></sup>-mediated cell oxidative stress which occurs at reoxygenation after hypoxia. In perspective, Mn<sup>II</sup>(Me<sub>2</sub>DO2A) might be used to reduce ischemia–reperfusion organ damage in acute vascular diseases, as well as to extend the viability of explanted organs before transplantation.</p> </abstract>