The Mechanism Of Toxicity And Cell Energy Metabolism Disorder Caused By Reactive Carbonyl Species Induced Oxidative Stress

Reactive carbonyl species(RCS) include a large number of biological compounds with one or more carbonyl groups that are continuously produced in metabolism of sugar, lipid peroxidation(LPO) and food processing. RCS are electrophilic and therefore highly reactive toward different cellular constituents majority of which are nucleophiles, and can lead to cell damage. Methylglyoxal(MG) and glyoxal(GO) are two kinds of dicarbonyl compounds of RCS with high activity. MG and GO can alter protein structure and function by inducing oxidative stress and carbonyl stress, leading to inflammation and diabetes, non-alcoholic steatohepatitis(NASH) and so on. At present, the mechanism of cytotoxicity of RCS include inducing oxidative stress, carbonyl stress, crosslinking of protein and protein or nucleic acid, gene mutation and cell apoptosis. RCS can cause apoptosis through the mitochondrial pathway, but the mechanism of mitochondrial damage needs to be further explored. Therefore, the article investigated the mechanism of cytotoxicity of two kinds of RCS from oxidative stress, mitochondrial membrane potential(MMP) change, fatty acid β-oxidation(FAO) and so on aspects.1. To research the mechanism of oxidative stress induced by RCS lead to the cytotoxicity, cytotixic test detection and reactive oxygen species(ROS), LPO, concentration of H2O2 of oxidative stress index and MMP were detected. The results showed that the vitality of hepatocytes(BRL 3A) and embryonic fibroblasts(3T3-L1) decreased, the cytotoxicity enhanced, the formation of ROS increased and the MMP decreased when RCS concentration was increased. The RCS capture agent aminoguanidine(AG), superoxide anion scavenger Trolox, catalase, hydroxyl scavenger mannitol can significantly inhibited the effects of GO.2. To research oxidative stress induced by RCS can lead to cellular energy metabolism disorder, ATP level detected by HPLC, fatty acid transport related proteins by western blot and enzyme activity detection was studied. The results showed that GO significantly decreased the ATP content of BRL 3A cells, while AG, catalase and Trolox could restored the level of ATP. The expression of fatty acid binding protein(FABP) and fatty acid transport protein(CD36) were decreased significantly, when the concentration of RCS were increased in BRL 3A and 3T3-L1 cells. And these may be the mechanism of NASH induced by RCS. The carnitine palmitoyltransferase-1(CPT1) activity was inhibited by RCS with time selectively. It was proved that the intake of fatty acids into mitochondrial may be one of the mechanisms of FAO dysfunction. And the expression of insulin receptor substrate-1(IRS-1) was decreased induced by GO in BRL 3A and 3T3-L1 cell. The expression of IRS-1 was decreased and serine 307 phosphorylation of IRS-1(p-IRS-1 Ser307) was increased induced by MG in 3T3-L1 cell, and resulted to resulin resistance(IR), which can further confirmed FAO dysfunction.In summary, two kinds of RCS lead to cell mitochondrial energy metabolism disorder was through induction of oxidative stress. And the mechanism of mitochondrial energy metabolism disorder probably was:(1) through inhibiting the expression of fatty acid transport protein;(2) through inhibiting the activity of CPT1 in a certain time period. RCS can inhibited the accumulation of lipid and may be the mechanism of NASH. And the cytotoxic mechanisms of two kinds of RCS was:(1) cell energy metabolism disorder induced by oxidative stress;(2) oxidative stress;(3) MMP decreased;.