Study On The Neuroprotective Effects And Mechanisms Of Photic Stimulation In Mice Models Of Depression

Objective: In this paper,the neuroprotective effect of specific forms of photic stimulation(PS)on depression was the main research content,and the effects and possible mechanisms of PS with a frequency of 40 Hz,a duty cycle of 50%,and an illumination of 500 lux on depression-like behavior,synaptic plasticity,neuroinflammation,neuronal survival and apoptosis in mice in the depressed model were discussed.Methods: Male C57BL/6J mice underwent 5 days of forced swimming(FS)to establish a depression mouse model,and were treated with PS(frequency 40 Hz,duty cycle 50%,illumination 500 lux)for 4 weeks.Depression and anxiety-like behaviors in mice were evaluated by the following behavioral experimental observations: open field test(OFT),forced swimming test(FST)and tail suspension test(TST).Western blot was used to determine the expression levels of synapse-related proteins in the prefrontal cortex(PFC)and hippocampus,including synaptophysin(SYP),PSD95,NMDA-related receptors(NR1,NR2 A,NR2B),apoptosis-related proteins Bax and Bcl-2 levels and expression of possible signaling pathway protein BDNF/AKT/GSK3β.Immunofluorescence staining was used to detect the levels of microglia,astrocytes and the number of neurons in the CA1 and DG regions of the hippocampus.The levels of IL-1β,TNF-α and IL-6 proinflammatory cytokines in PFC and hippocampus were detected by enzyme-linked immunosorbent assay(ELISA).Results: A 5-day FS depression mouse model was successfully established;PS improved the depression and anxiety-like behaviors of FS depression model mice;PS can increase the levels of synapse-related proteins in the PFC and hippocampus of FS depression model mice,and promote synaptic plasticity;PS reduced the number of microglia in the hippocampus of FS depression model mice and improved the down-regulation of astrocyte levels;Moreover,PS reduced the levels of IL-1β,TNF-α and IL-6 in PFC and hippocampus;PS can inhibit apoptosis and promote neuronal survival.These results suggest that PS can exert neuroprotective effects on FS depression model mice in multiple ways.PS also significantly up-regulated BDNF expression,enhanced AKT activity and inhibited GSK3β activity,indicating that the neuroprotective effect of PS on FS depression model mice may be related to the BDNF/AKT/GSK3β pathway.Conclusion: PS can play a multi-level neuroprotective effect on depression model mice and promote the improvement of depression-like behavior,suggesting that PS may be an effective new antidepressant method,and also provides an experimental basis for the clinical antidepressant of PS and new ideas.