Protective Effects Of Aldose Reductase Inhibitor On Microglia Mediated Neuronal Injury

BackgroundCentral nervous system disease is a serious hazard to human health.It’s a common disease that involves the interaction of a variety of cells and cytokines. As the immune effector cells in the brain,microglia plays an important role in the central nervous system damage and repair process.Microglia can both protect neurons and release large amounts of pro-inflammatory cytokines and toxins leading to neuronal injury and death. Lipopolysaccharide(LPS) as a main component of the cell wall of Gram-negative bacteria, is typical of microglia activator whitch can induce potent microglial inflammation. After activation of microglia proinflammatory gene transcription regulation translation and expression, the synthesis of a series of inflammatory mediators, including IL-1β, TNF-α and other proinflammatory cytokines such as ROS, NO and other cellular toxic substances. Aldose reductase(AR) is one of the key rate-limiting enzyme in the polyol pathway of glucose metabolism and the only enzyme conversion of glucose to Sorbitol in vivo. Studies have shown that aldose reductase can affect oxidative stress and inflammation processes, it is closely related to the inflammation process.ObjectiveThis experiment study on the inhibition of aldose reductase inhibitors(ARIs) on LPS-activated microglia inflammation and it’s protection effect on neurons and mechanism.Methods1.Microglial cells were cultured in vitro, purified, and the inflammation model was established by the cells stimulated with LPS. By Griess and ELISA method we detected the amount of NO, NF-α and IL-6 in each group to verify Anti-inflammatory effects of aldose reductase inhibitors.2.By Westernblot technology, we examined whether aldose reductase inhibitors inhibit the activation of NF-κB, to investigate the protective mechanism of aldose reductase inhibitors on LPS-activated microglia-mediated neuronal injury.3.Neurons were cultured in vitro, purified, activated microglia conditioned medium was added neuronal cell culture system.We used MTT method to detect the condition of the media on neuronal injury,and the protection of aldose reductase inhibitors to the injury.Results1.The amount of NO, TNF-αand IL-6 were significantly increased in LPS activated microglia cell culture medium.Added four kinds of different concentrations ARI(Zopolrest:5,10,50,100nmol/L), the amount of NO, TNF-α and IL-6 decreased significantly compared with LPS activation group(P<0.05) in microglial cell culture medium.As the concentration of ARI increased the amount of NO, TNF-α and IL-6 decreased,showing a concentration-dependent manner. But, the amount of TNF-α and IL-6 was no difference in 100 mmol/L and 50 mmol/L Zopolrest group.2.Compared with the control group, LPS stimulation activated microglia IκB and NF-κB protein phosphorylation levels were increased(P<0.05). Resulting in record factor NF-κB activation, aldose reductase inhibitors can reduce the stimulation of activated microglia IκB and NF-κB protein phosphorylation level(P<0.05), inhibitingthe activation of transcription factor NF-κB.3.LPS activated microglia cell culture supernatant acting on the neurons, neuronal viability decreased(P<0.05). ARIs added microglia cell conditioned culture supernatant acting on the neurons, neuronal viability increased significantly compared with activation group(P<0.05).Conclusion1.LPS could induce microglia inflammatory reaction, and secretion of NO, TNF-α and IL-6 was significantly increased in activated microglia,Causing injury to neurons.2.By inhibiting NF-κB inflammation pathway, aldose reductase inhibitors inhibiting microglial inflammatory response, showing protective effect on microglia-mediated neuronal damage.