Evaluation of the in vivo antioxidative activity of redox nanoparticles by using a developing chicken egg as an alternative animal model

Abstract

Antioxidants have been demonstrated to exert beneficial effects as pharmacotherapies for cardiovascular diseases. The in vitro systems generally employed to evaluate antioxidants, however, are limited by having no appreciable in vivo redox status of the antioxidants. Therefore, we used our developing chicken egg model to evaluate the in vivo antioxidative activity of a redox nanoparticle possessing 2,2,6,6-tetramethylpiperidine-1-oxyl (RNP(O)). The 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH) elicited strong oxidative stress and its LD50 value for chick embryos was 3.5±0.9mg/egg. The low molecular weight nitroxide compound, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), which is known to have the highest level of antioxidant activity, showed no significant protective effect against AAPH-induced embryo lethality. On the contrary, RNP(O) had potent protective effects against AAPH-induced embryo lethality. Moreover, RNP(O) could significantly suppress the production of lipid peroxides in chick serum induced by hydrocortisone. Since RNP(O) has a longer retention time in blood than TEMPOL, RNP(O) may protect the embryo against lethal oxidative stress by suppressing lipid peroxidation. The validity of in vivo experiments using developing chicken eggs was supported by our data, where RNP(O) was determined to elicit strong antioxidative activity in vivo, irrespective of the lack of a significant difference in the in vitro activity between low-molecular weight TEMPOL and RNP(O). Our results support the use of the developing chicken egg model to evaluate the potential in vivo antioxidative activity of RNP(O).

Hydrogen Sulfide and Cellular Redox Homeostasis

“…In the late case, ROS may not only kill invading pathogens and microbes but also damage the components of the cell, including proteins, lipids, carbohydrates, and DNA [ 16 ]. Overwhelming evidence indicates that oxidative stress is involved in the pathophysiology of the wide array of human diseases, including cancer [ 17 ], cardiovascular disease [ 18 ], AIDS [ 19 ], diabetes mellitus [ 20 ], and neurodegenerative disorders such as aging, Parkinson's disease, and Alzheimer's disease [ 21 , 22 ].…”

Effect of heteroatom and functionality substitution on the oxidation potential of cyclic nitroxide radicals: role of electrostatics in electrochemistry

“…The persistent nature of these nitroxides originates from: (1) electron delocalization along the N-O bond and (2) the stabilization against combination and disproportionation by the four α-methyl groups adjacent to the N-O centre. Nitroxides have many applications, including as spin probes and spin labels, 1,2 superoxide dismutase mimics, 3,4 antioxidants [5][6][7] and control agents in 'living' radical polymerization. 8,9 Early work, as summarised by Rozantsev, 10 focussed on the comprehensive synthesis of functional nitroxides, including TEMPO, pyrrolidine (PROXYL) and pyrroline radicals as well as various derivatives, and their applications in biological systems.…”

Embryonated chicken eggs: An experimental model for Pythium insidiosum infection

“…Embryonated chicken eggs as an experimental model in fungal infection research have been shown to be effective for evaluating the virulence and pathogenicity of experimental infections by Aspergillus fumigatus and Candida albicans . Indeed, many studies have demonstrated that the developing chicken egg is a useful model for the in vivo evaluation of antioxidative, antiviral and anti‐angiogenic activities, as well as in drug toxicology studies …”