The Characteristic And Mechanism Of Autophagy During Sleep-wake Cycle And Sleep Deprivation In Medial Prefrontal Cortex In Mice

Objective To observe the characteristic and mechanism of autophagy during sleep-wake cycle and sleep deprivation in medial prefrontal cortex(m PFC)in miceMethods Male C57BL/6 mice(aged 8-10 weeks,weight: 23-26g)were used in this study.Total sleep deprivation for 6 hours(SD6 h)and 12 hours(SD12 h)were performed by gentle handing.Animals were randomly divided into SD6 h,SD12 h and their control group(n=10-12/group).Western blot was used to detect the levels of superoxide dismutase 2(SOD2),catalase,silent information regulator 3(Sirt3),microtubule associated protein1 light chain 3 –?(LC3-?),P62(also known as SQSTM1),AMP-activated protein kinase(AMPK),mammalian target of rapamycin(m TOR),p-AMPK,p-m TOR in m PFC.Immunofluorescence staining was used to observe the expression of lysosomal-associated membrane protein 1(LAMP-1)in m PFC.And Dihydroethidine(DHE)staining was applied to detect the level of O2-.Result1.The autophagic flux was increased,the expression of P62 was lower,and the expression of Beclin-1 was relatively higher in m PFC neurons during nighttime compared with that during the daytime.2.The expression levels of SOD2(P<0.05),catalase(P<0.05)and sirt3(P<0.05)were significantly increased in m PFC neurons after SD6 h(P<0.05).There was no significant change in the expression of SOD2,catalase and sirt3 after SD12 h in m PFC neurons.However,both SD6 h and SD12 h substantially increased the level of O2-in m PFC neurons(P<0.05).3.SD6 h and SD12 h lead to increased expression of LC3-?(P<0.05)and P62(P<0.05)level in m PFC neurons.Similarly,the expression of Beclin-1(P<0.05)and LAMP-1(P<0.05)were also dramatically increased in m PFC neurons.4.There was no significant difference between the SD group and control group in expression levels of AMPK and m TOR in m PFC neurons after SD6 h;After SD12 h,the expression level of m TOR protein was significantly decreased in m PFC neurons(P<0.05),but there was no significant difference in the expression of AMPK.Conclusion1.The autophagy activity is lower during sleep,but is higher during wakefulness in m PFC neurons.2.Sleep deprivation leads to increased oxidation activity in the m PFC while the level of antioxidant activity is transiently elevated.3.Both SD6 h and SD12 h induce the elevation of autophagy activity in m PFC.4.SD12 h inhibits the m TOR signaling pathway in m PFC neurons,which contributes to upregulating of autophagy.