Effect Of Sleep Apnea Intermittent Hypoxia On Avtivity And Apoptosis Of Primary Cultured Rat Cortical Neurons In Vitro

Backgrounds and Obsjectives:Sleep Apnea Hypopnea Syndrome is one of commonest sleep breathing disorders, and the typical pathophysiologic hallmarks are intermittent hypoxia and sleep fragmentation. SAHS can cause multiple systems diseases, such as:cardiovascular, endocrine, genitourinary, blood and neuropsychiatric systems. Currently, the cognitive dysfunction caused by SAHS takes more and more attention as a common complication in the nervous systerm,especially in pediatric patients with SAHS.Intermittent hypoxia was always considered as an intervention factor in research on SAHS.The research was simplified whereas most of aims can be achieved. In this study,research were done on effect of intermittent hypoxia on neuronal avtivity and apoptosis of primary cultured rat embryo in vitro.The aim of this study was surmise the role of intermittent hypoxia in pathogenesis of sleep apnea syndrome with cognitive impairent, and investigate the pathogenesis of cognitive impairment in sleep apnea hypopnea syndrome.Meheods:1.Primary rat embryo cortical neurons were cultured in vitro.TubulinB monoclonal antibodies were made as an neuronal marker in identified neurons by immunizing fluorescence staining when cortical neurons were cultured at 6 days.2.Cultured neurons were randomly divided into7 groups,simulate intermittent hypoxic exposure mode is:hypoxia-oxygen cycle. A, B, C, D group per cycle hypoxia (1.5% O2) was 15s, normal oxygen (21% O2) were 1min45s,3min45s,5min45s and 8min45s, exposed to 60 cycles; E group per cycle hypoxia (1.5% O2) 30s, normal oxygen (21% O2) 3min45s, exposed to 60 cycles; F group received continuous hypoxia (1.5% O2) 15min; H group was setted in the incubator 6 hours standard, as on control.3.Tetrazolium salt (MTT) assay and 4,6-diamidino-2-phenylindole hydrochloride (DAPI) staining were used to test neuronal activity and apoptosis after being exposed. In addition,compare the difference between survival and apoptosis rate of each group and analyze the correlation with exposure conditions.Results:1.There were significant difference of effects between all subgroups of intermittent hypoxia with the continued hypoxia group on neuronal activity and apoptosis(P<0.01).2.The effects of intermittent hypoxia groups with different frequency and time were no difference on neuronal activity and apoptosis (P> 0.05).Conclusion:1. Under the same conditions of hypoxia extent and hypoxia cumulative time, the way of intermittent hypoxia is moer likely to cause neuronal activity decreasing and apoptosis than sustained hypoxia.2.Intermittent hypoxia can cause neuronal activity decreasing and apoptosis significantly, which that may be an important reason for cognitive impairment in sleep apnea syndrome.