Ozone Intraperitoneal Injection Prevents The Depression By Ameliorating Microglia Re-activation In Depressed Mice

Objective:Depression is a common psychological and psychiatric disease that affects not only the normal life health of patients but also caused the heavy economic and psychological burden on the patients' families.In the past,people have made a great deal of exploration on molecular,cell and signal pathways related to depression,but the pathogenesis of depression is still not clear.Numerous studies have confirmed that neuroinflammation caused by microglial activation plays an important role in depression.At present,drugs are the main treatment for depression.In addition to drugs,psychotherapy,electroshock and vagal nerve stimulation therapy have been shown to be effective in relieving depression.However,drugs with varying degrees of side effects,psychological therapy takes time,electric shock and vagus nerve stimulation therapy will produce different results for different patients.Therefore,there is a need to find a way to reduce side effects and to treat depression effectively.Ozone(O3)has anti-inflammatory,anti-infective,enhance immunity,oxygen supply to the hypoxic tissue and other functions.In recent years,ozone therapy has been widely used in clinical medicine,studies have showed that ozone therapy can be limited treatment of scapulohumeral periarthritis,post-herpetic neuralgia,femoral head necrosis,diabetic foot,viral hepatitis and other diseases.So far,there is no report of the ozone prevention and treatment of depression.Therefore,this study mainly explore the changes of microglial cells and the level of IL-1?,IL-6 and TNF-?,and clear whether the pathogenesis of depression induced by neuroinflammation by activied microglia.In addition,ozone were used to depression mice in order to analyze the behavioral changes and the number of microglia in thehippocampus,prefrontal cortex and amygdale and the levels of inflammatory cytokines IL-1?,IL-6 and TNF-?.Methods:Forty mice were randomly divided into four groups,stress+ saline group,stress+ozone group,control + saline group and control +ozone group.The stress+ saline group and the stress +ozone group mice were restrained for 7 days and restrained for one hour every day to prepare the depression model.The stress+ ozone group and the control+ozone group were treated with ozone(80?g / ml)intraperitoneal injection.Ozone intervention was given three days before the depression model as an ozone preventive intervention,ozone were given after the depression model as an ozone therapeutic intervention.Tail suspension test(TST),forced swimming test(FST),Novelty suppressed feeding test(NSFT)and open field test(OFT)were used to test the behavioral changes in each group.The microglial marker IBA1 immunohistochemistry was used to detect the changes of microglia in the hippocampus,prefrontal cortex and amygdala.PT-PCR was used to detect the levels of IL-1?,IL-6 and TNF-? in the hippocampus,prefrontal cortex and amygdala.Results:In the ozone preventive intervention,ozone can improve the behavior of depression mice,reduce the number of activated microglial cells in the prefrontal cortex and hippocampus,and decrease the levels of inflammatory cytokines IL-1? and TNF-?.In the ozone therapeutic interventions,the ozone did not improve the behaviors in depression mice.There was no difference in the number of microglia activated in the prefrontal cortex,hippocampus and amygdala between stress +saline group and model+ozone group(P <0.05).The therapeutic intervention failed to reduce the levels of IL-1?and TNF-? in the prefrontal cortex and hippocampus.Conclusion:Ozone preventive intervention can effectively alleviate the depression-like behavior of depression mice,reduce the number of activated microglia of hippocampus,prefrontal cortex and amygdala,and decrease the levels of inflammatory cytokines IL-1?,IL-6 and TNF-?.While the therapeutic intervention of ozone did not.