Dative injury that significantly contributes to ischemia/reperfusion (I/ R) injury
Dative injury that significantly contributes to ischemia/reperfusion (I/ R) injury [24-26], we considered in this work the question of whether DOR activation can enhance Mangafodipir (trisodium) site antioxidant ability and thus attenuate oxidative injury in the brain exposed to I/R stress. For the purpose of comparison, we also determined whether DADLE affects the expression of some inflammatory cytokines such as interleukin (IL)1 and tumor necrosis factor (TNF), which are known to play a role in I/R injury [25-27].group, which could be largely reduced by DOR activation with DADLE. Next, we investigated if DOR activation preserves the antioxidant mechanism because the brain is extremely vulnerable to free radical attack that occurs in ischemia/ reperfusion [24,25,30-32]. Since superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) are the most important enzymes to protect against oxidative stress in the brain [24,25], we measured their activities in the cortex among three groups. As shown in Figure 2B, I/R largely decreased SOD activity from 204.3 ?5.39 U/mg protein in the control to 162.2 ?5.91 U/mg protein in the I/R group (P < 0.0001), while DOR activation with DADLE significantly increased SOD activity by 22.5 U/mg protein (P < 0.0001) in the ischemic cortex. By contrast, GSH-Px activity showed a similar change in response to I/R and DADLE treatment. I/R stress significantly decreased GSHPx activity by 23 (18.72 ?0.89 U/mg protein in the I/R group vs 24.31 ?0.78 U/mg protein in the control, P < 0.0001), which was markedly reversed by DADLE (+ 3.50 U/mg protein over the level of the I/R group, P < 0.0001) (Figure 2B). These data suggest that I/R stress impairs the antioxidant mechanism, while DOR activation partially restores it. Since a reduction of antioxidant enzymes leads to an increase in free radical products[24,25,30-32], especially malondialdehyde (MDA) that damages membrane integrity, we compared the changes in cortical MDA in all groups. The results showed that I/R induced a 40 increase in MDA (8.99 ?0.41 nmol/mg protein in the I/R group vs. 6.43 ?0.44 nmol/mg protein in the sham control group, P < 0.0001), while DADLE treatment resulted in a significant decrease in the content of MDA (-15.6 vs. I/R alone, P < 0.05) (Figure 3A). These results were well consistent with those of antioxidant enzymes, SOD and GSH-Px. To further ascertain the effect of DOR activation on the antioxidant mechanism, we examined the changes in NO, another critical free radical that causes brain injury in ischemia/reperfusion [24,25]. The data showed that I/R almost doubled the level of NO (2.07 ?0.27 mol/g protein in the I/R group vs. 1.16 ?0.16 mol/g protein in the control, P < 0.0001). This large increase was greatly inhibited by the treatment with DADLE (-29.8 , P < 0.0001), lending further support PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/27488460 for the DOR-mediated inhibition of free radical production (Figure 3B). In addition to oxidant free radicals, inflammatory cytokines have been shown to play a role in ischemic injury [25-27]. Therefore, we examined, by quantitative real-time PCR, whether DADLE affects the expression of IL1 and TNF that are known to be involved in neuronalResultsOur previous work and those of others have clearly demonstrated that DOR activation with DADLE or other DOR agonists attenuates hypoxic/ischemic injury in cortical neurons and reduces ischemic infarction in the cortex [323]. Since caspase activity plays a key role in apoptotic signal transduction and is a crucial indicator of isc.