Enzyme activity in the digestion of reactive oxygen decreased.

Reactive oxygen (ROS) includes oxygen free substrates such as superoxygen anions, hydroxy free substrates and hydrogen peroxide and monoline oxygen, these substances have a strong oxidation capacity, has a more active chemical reaction than molecular oxygen, oxygen-needing cells in the metabolic reaction and external environmental factors stimulated to produce ROS.
cell level, Cr(VI) enters the cell and is reduced to low-cost chromium within the cell, producing a large amount of ROS in the process.
the accumulation of ROS in cells is a key factor in the toxicological effects of Cr (VI) cells.
recent studies have shown that Cr (VI) can lead to in-cell ROS accumulation by reducing the activity of antioxidant enzymes in cells, promoting the expression of ROS synthesis-related enzymes, and interfering with mitochondrial energy transfer.
1, the enzyme activity of the elimination of ROS decreased cells in the antioxidant system, a variety of enzymes and peptides have the effect of eliminating ROS, Such as superoxide dismutase( SOD), hydrogen peroxide enzyme (catalase, CAT), and prototype glutathione (reduced glutathione, GSH), thiooxygenic protein and its reductase (thioredoxin/thioredoxintase, Trx/TrxR), etc., can lead to increased levels of INROS only when the reduction system within the cell is not sufficient to remove the newly produced ROS.
physiological studies showed that Cr(VI) entered the animal body can lead to SOD, CAT activity in a variety of tissues, including liver tissue, epiderm tissue, GSH/GSSH ratio significantly decreased.
at the cellular level, TrxR activity was inhibited and Trx oxidation levels increased in the human bronchoder epiderm beAS-2B after Cr(VI) was infected.
above results show that Cr(VI) consumes a large number of in-cell reductases during the reduction process, breaking the body's oxide reduction balance, resulting in damage to the in-cell antioxidant system, resulting in a cumulative effect of ROS.
Wang and others found that in colorectal cancer cells associated with colorectalitis in mice, Cr(VI) also led to a decrease in SOD and CAT protein expression levels, indicating that Cr (VI) not only consumes mature antioxidant enzymes in cells, but also interferes with the expression of such enzymes.
2, ROS synthesis-related enzyme expression level increases ROS in addition to aerobic metabolism as a by-product, but also as a second messenger, regulating normal physiological activity of cells, a variety of signals in the body can stimulate the production of ROS, such as growth factors, cytokines and so on.
cells are found in the enzyme line that synthesizes ROS, NADPH oxidase (NADPH oxidase, NOX).
NOX is located on a variety of cytokine membranes, with cytochrome C and FAD groups, consisting of gp91phox, p22phox, p47phox, p67phox, p40phox and Rac six sub-groups.
in BEAS-2B cells, Cr(VI) poisoning can lead to a significant increase in the expression level of several sub-kilos of NOX, while the level of p47phox phosphorylation increases and transfers to the membrane.
that Cr(VI) promotes cell synthesis of new ROS in addition to producing ROS directly during the reduction process.
3, interference with mitochondrial energy transfer mitochondria is the center of in-cell oxidation reaction, mitochondria through the electron transmission chain to pass electrons to oxygen, and manufacture ATP.
Yuan, etc. and Xiao, etc., systematically studied the mitochondrial energy metabolism mechanisms of cr(VI) affecting human embryonic liver cell L-02, and the results showed that Cr(VI) could cause ROS accumulation by blocking the electron transfer of mitochondrial cell respiratory chain I (mitochondrial respiratory chain I, MRCC I), and interestingly, in L-02 cells, soD, CAT and other antioxidant expression levels did not change significantly.
the mechanism by which Cr(VI) causes ROS accumulation to vary in different cells.
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