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Depletion Of Cd-Group Case Study

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The high MDA level mentioned in Cd-group our investigation was associated with a marked depletion of renal GSH by Cd exposure due to the direct binding of Cd to enzyme active sites, if it contains –SHgroups77. Significant decrease in the levels of these non-enzymatic antioxidants in Cd toxicity could lead to increased susceptibility of the renal tissue to free radical damage .GSH is a non-enzymatic antioxidant which acts as a first line of defense against oxidative stress78. The significant reduction in GSH levels that was recorded can be attributed to the increased use of GSH (by the renal tissues) to mop up excessive ROS that were generated during the process of Cd-induced renal injury 60. The depletion of GSH also seems to be a prime…show more content…
It was reported that oral exposure to Cd via drinking water (250 mg/L) during 10 and 30 days induced significant decreases in renal total SOD activity, as well as CAT70.
Different effects of Cd on the enzymatic antioxidant system observed in different studies are contradictor and could be explained not only by differences in duration of exposure and applied Cd doses, but also by the activation of nature of defense systems namely GPx via increased gene expression that is followed by the increase of antioxidant enzymes .In a study82, it has been reported that the influence of Cd on serum GPx activity depends on Cd dose, since exposure to 5 mg Cd/L for 6 months produced increase in GPx activity, while exposure to 50 mg Cd/L for the same period of time led to the decrease in GPx activity. Several mechanisms have been proposed to explain Cd-induced renal toxicity after both acute and prolonged exposure, with clear evidence of the apparent role of oxidative stress. Acute Cd intoxication generally inhibits the activity of antioxidative enzymes SOD, CAT and GPx. Many studies demonstrated decreased levels of enzymatic antioxidants in the kidney of animals exposed to prolonged Cd intoxication .These findings can be explained by direct Cd/enzyme interaction, displacement of metal cofactors from the active enzyme sites, while the decrease in GPx activity could be attributed to competition between GPx and metallothionein for S-aminoacids83,75. However, several
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