Effects Of Sleep Deprivation On Learning,memory And Expression Of Autophagy-related Protein Of Hippocampus Of APP/PS1 Double Transgenic Mice

Objective: To investigate the effects of sleep deprivation on learning and memory in mice with Alzheimer's disease,and to determine the expression of autophagy-related proteins in the hippocampus of these mice.To elucidate the effect of sleep deprivation on the pathogenesis of Alzheimer's disease,and to indicate the significance of autophagy in this process.Methods:(1)24 APP/PS1 double transgenic mice were randomly divided into sleep deprivation group(SD group)and control group,12 in each group.The sleep deprivation model was established by modified multi-platform sleep deprivation,and the mice of SD group were continuously deprived sleep for 72 hours.(2)To observe the general situation of the two groups of mice,and to detect their behavioral changes with Morris water maze.(3)The mice in the two groups were anesthetized by the abdominal cavity,and the hippocampus was decapitated after left ventricular perfusion.To detect the morphological changes of hippocampal neurons in each group by HE staining.(4)Immunohistochemistry(IHC)method was used to detect the expression of ?-amyloid 42(A?42)both in the medial cortex and hippocampus of two groups.(5)The expression of autophagy-related protein LC3 in hippocampus were detected by IHC.(6)Western blot(Western Blot,WB)method was used to detect the expression level of LC3-II and p62 in hippocampus of two groups of mice.Results: After 72 hours of sleep experiment intervention,the changes of each index in the two groups of mice were compared.1.Changes of general conditions after sleep deprivation intervention: SD group was apathetic,loss of appetite,dull hair,and irritability.The control group had no significant changes compared to the previous period.2.Behavioral changes:(1)Comparison of the latency time of these mice in experimental group in positioning navigation,the results showed that the sleep deprivation group(41.87±16.65)s was longer than the control group(21.49±13.48)s.The difference was statistically significant(t =-3.13,P <0.05);(2)The number of mice crossing the platform in the experimental group was significantly different from the control group(t = 4.06,P <0.01),compared with the control group(40.21±12.58)s,the time of target quadrant of the experimental group(25.16±10.81)s was significantly shortened.The difference was statistically significant(t= 2.72,P<0.05).(3)The results of mice search strategies showed that the experimental group were mainly random and marginal,while in the control group was mainly linear and trending.The difference was statistically significant(Z=-2.237,P<0.05).3.Morphological changes of hippocampal neurons: The hippocampal neurons in the control group were well-organized,with clear boundaries and neatly arranged,but the sleep deprivation group had loosely arranged neurons in the hippocampus and the cell body was smaller than the control group by HE staining.The number of nucleolus shrinks,and the number is reduced compared with the normal control group,and the boundary line around the cells is unclear.4.Comparison of the expression of A?42positive reaction products in the medial cortex and hippocampus of the two groups of mice: A?42 immunoreactivity was extensively present in SD and control groups in the temporal cortex and hippocampal neurons,and accumulated in the extracellular matrix.The size of A? immunoreactive substances in SD mice was significantly increased.5.Changes of expression of autophagy-related proteins in hippocampus of mice after sleep deprivation intervention:(1)The expressed level of autophagy-related protein LC3 immunoreactivity in the hippocampus of the sleep deprived group was higher than that of the control group;(2)The expression of autophagy-related proteins LC3-II and p62 in mice were up-regulated in sleep-deprived group compared to the control group by western blotting,and there was a significant difference in the relative expression of LC3-II protein(t =-2.61,P <0.05).Conclusions:(1)Sleep deprivation can cause cognitive impairment and hippocampal neuronal damage in APP/PS1 double transgenic mice.(2)Sleep deprivation can cause increased expression of senile plaques aggregated of A?42 in the hippocampus and temporal cortex of APP/PS1 double transgenic mice.(3)Sleep deprivation can up-regulate autophagy activity in APP/PS1 double transgenic dementia mice,which may be the mechanism that mediates the onset and progression of Alzheimer's disease.