快速动眼睡眠剥夺对大鼠学习、记忆能力及海马组织自噬的影响

目的 探讨快速动眼(rapid eye movement,REM)睡眠剥夺后与大鼠认知相关的行为学变化及脑内海马组织中自噬相关蛋白的表达水平。方法 健康成年雄性大鼠经过筛选后分为空白对照组(CC组)、环境对照组(TC组)、睡眠剥夺组(SD组),每组各6只; 采用改良多平台睡眠剥夺法(modified multiple platform method,MMPM)建立睡眠剥夺模型,连续剥夺5 d后利用Morris水迷宫检测大鼠认知功能; 用蛋白质印记法(Western Blot,WB)检测自噬相关微管蛋白(LC3)及SQSTM1/P62的表达水平变化。结果 与CC组和TC组比较,SD组大鼠毛色无光泽、易激惹、体重下降(P<0.05)。SD组与其他2组比较,逃逸潜伏期延长、目标象限时间减少(P<0.05)。WB显示SD组与其他2组比较,大鼠脑内海马组织自噬相关蛋白LC3-II表达水平上升,P62水平下降(P<0.05)。CC组与TC组大鼠比较,体重、学习记忆能力、海马组织自噬蛋白表达水平均无明显差异(P>0.05)。结论 睡眠剥夺后可损害大鼠学习及记忆功能,海马组织中自噬水平上调提示自噬活动可能参与睡眠剥夺介导的认知功能障碍过程。     

神经节苷脂对脑外伤后脑线粒体呼吸功能和钙泵活性的保护作用

目的研究大鼠脑外伤后脑线粒体功能变化及神经节苷脂ＧＭ１保护作用。方法从牛脑组织中提取ＧＭ１治疗ＳＤ大白鼠自由落体脑外伤，测定脑线粒体呼吸功能变化和线粒体、微粒体质膜钙泵活性变化。结果发现脑外伤后８小时和１６小时脑线粒体Ⅲ态呼吸耗氧速率、呼吸控制率、磷氧比、氧化磷酸化效率及脑线粒体和微粒体质膜钙泵活性低于正常组，差异有显著性意义（Ｐ＜０．０５或０．０１）；经ＧＭ１治疗后上述指标多数有明显上升，并与正常组相近。结论提示脑外伤后脑线粒体呼吸功能有明显障碍，并与线粒体和内质网钙泵活性下降一致；ＧＭ１能显著改善线粒体呼吸功能和提高钙泵活性。     

间歇缺氧及睡眠剥夺大鼠血管内皮细胞相关指标的变化***☆

背景：血管内皮功能损坏是睡眠呼吸暂停的病理基础。 目的：观察间歇缺氧、睡眠剥夺对SD大鼠有创动脉收缩压及血浆一氧化氮、内皮素、降钙素基因相关肽水平的影响。 方法：将3月龄雄性SD大鼠16只随机等分为2组，模型组大鼠每天置入睡眠剥夺合并间歇性缺氧条件10 h (22：00-08：00)，单纯睡眠剥夺条件12 h(08：00-20：00)，剩余时间置大鼠笼饲养。对照组无睡眠剥夺、无缺氧条件饲养。 结果与结论：造模8周后，与对照组比较，模型组大鼠有创动脉压明显升高(P < 0.01)，血浆一氧化氮、降钙素基因相关肽水平显著降低(P < 0.01)，血浆内皮素水平显著升高(P < 0.01)。说明间歇性缺氧、睡眠剥夺可以引起SD大鼠血压增高，血管内皮功能受损。     

左归丸对大鼠慢性脑缺血线粒体呼吸链酶复合物活性的影响

目的探讨左归丸对慢性脑缺血线粒体呼吸链酶复合物活性的影响及其机制。方法将实验大鼠随机分为对照组、假手术组、慢性脑缺血组和左归丸治疗组,各8例。后两组大鼠采用双侧颈总动脉结扎法建立慢性脑缺血大鼠模型。左归丸治疗组于术后3周开始每天予以左归丸液灌胃,剂量为4.0 g/kg/d。术后6周,测试各组大鼠脑皮质线粒体活性氧(ROS)水平及线粒体呼吸链酶复合物活性测定。结果与对照组及假手术组比较,慢性脑缺血组大鼠的脑的线粒体ROS水平明显增高(P0.01),呼吸链酶复合物Ⅰ-Ⅳ活性均有不同程度的明显降低(P0.01);接受左归丸治疗组的大鼠的脑的线粒体ROS水平明显降低(P0.05),呼吸链酶复合物Ⅳ(COX)活性得到明显改善(P0.05)。结论左归丸可能通过修复线粒体COX的活性水平,改善线粒体功能,减少ROS的生成,从而起到对慢性缺血的保护作用。     

大鼠脑出血后血肿周围组织线粒体功能变化的研究

目的:研究大鼠脑出血后脑组织线粒体功能的变化。方法:以50 μL鼠尾血注入大鼠尾状核制作大鼠脑出血模型,注血后分别于12 h及1、3、7 d处死大鼠,断头,取血肿周围脑组织,测定不同时相点血肿周围组织线粒体功能(琥珀酸脱氢酶活性、呼吸控制率)。结果:出血后12 h线粒体呼吸控制率及琥珀酸脱氢酶活性无明显变化,1 d后呼吸控制率较对照组下降,3 d时线粒体呼吸控制率及琥珀酸脱氢酶活性均较对照组下降,出血后7 d线粒体琥珀酸脱氢酶活性、呼吸控制率则较对照组明显下降(P<0.01)。结论:脑出血早期(尤其在12 h之内)血肿周围组织线粒体功能无明显下降,晚期则明显受损。     

河北省老年人认知功能与睡眠质量关联分析北大核心CSCD

目的探讨河北省老年人认知功能与睡眠质量之间的关系。方法本研究为现况调查。通过分层、整群随机抽样纳入河北省老年人4427名,收集一般情况,评估匹兹堡睡眠质量指数量表(Pittsburgh sleep quality index,PSQI)、简易智能精神状态检查量表(mini-mental state examination,MMSE)。根据MMSE评分将老年人分为认知功能障碍组(n=2164)和认知功能正常组(n=2263)进行分析。结果认知功能障碍组和认知功能正常组间年龄、性别、婚姻状态、受教育程度、体质指数、吸烟、饮酒、睡眠质量[1.00(1.00,1.00)分vs.1.00(0.00,1.00)分]、入睡时间[1.00(1.00,3.00)分vs.1.00(0.00,3.00)分]、睡眠效率[0.00(0.00,1.00)分vs.0.00(0.00,1.00)分]、日间功能损害[0.00(0.00,0.00)分vs.0.00(0.00,0.00)分]差异具有统计学意义(P<0.05)。认知功能障碍组长睡眠(睡眠时长>9 h)者较认知功能正常组多(1.89%vs.0.93%,P=0.004)。校正混杂因素后,认知功能障碍与睡眠效率(OR=1.111)、日间功能损害(OR=1.165)、睡眠时长>9 h(以6~9 h为参照,OR=1.808)相关(P<0.05)。结论睡眠效率越差、日间功能损害越严重的老年人认知功能越差,睡眠时长>9 h较睡眠时长6~9 h的老年人认知功能差。     

脑外伤后脑线粒体功能和结构改变及神经节苷脂治疗作用

目的从牛脑组织中提取神经节苷脂ＧＭ１,研究其对脑外伤后脑细胞呼吸功能和结构保护作用。方法把ＳＤ大鼠分成正常组,生理盐水治疗的损伤对照组及ＧＭ１治疗的损伤治疗组。结果发现对照组伤后８小时和１６小时Ⅲ态呼吸耗氧速率（Ｒ３）,呼吸控制率（ＲＣＲ）,磷／氧比（Ｐ／Ｏ）及氧化磷酸化效率（ＯＰＲ）有明显降低,治疗组则明显增加,且与正常组相近。对照组皮层神经元细胞和线粒体超微结构有明显损害,治疗组损害明显减轻。结论其可能机制与ＧＭ１保护膜脂和膜酶活性,维持膜内外离子平衡,减轻水肿及减少自由基形成等有关     

睡眠剥夺对小鼠脑内细胞型朊蛋白表达水平的影响及可能的意义

目的 探讨小鼠正常昼夜节律下以及睡眠剥夺后大脑海马组织细胞型朊蛋白(PrP^C)和β-淀粉样前体蛋白(Aβ)表达水平的变化及PrP^C在睡眠剥夺诱导的认知损害中发挥的作用。方法 成年C57BL/6小鼠置于光照和黑暗交替环境中饲养2周后分别在开灯后4、8、12、16、20、24 h等6个时间点处死小鼠,每个时间点各8只,分别取海马、皮层2个部位的组织样本,采用酶联免疫吸附法检测PrP^C和Aβ的表达水平。成年小鼠按体重大小排序,完全随机分成3组,分别为正常对照组、环境对照组、睡眠剥夺组,采用改良水平台法对小鼠进行72h快速眼动睡眠剥夺,断头处死小鼠获取海马,分别采用Western Blot法和酶联免疫吸附法检测PrP^C和Aβ的表达水平变化。Halberg余弦分析PrP^C和Aβ在海马与皮层的昼夜节律变化特征。结果 单余弦分析显示PrP^C在皮层具有昼夜节律性(F=11.22,P<0.05)。Aβ在海马具有昼夜节律性(F=26.72,P<0.05); 睡眠剥夺后睡眠剥夺组海马PrP^C的表达水平(0.22±0.05)较正常对照组(0.64±0.16)和环境对照组(0.58±0.09)明显下调(F=4.366,P<0.05),睡眠剥夺组Aβ的表达水平(13.03±0.71)较正常对照组(8.22±0.8)和环境对照组(8.6±0.57)明显上调(F=14.511,P<0.05)。结论 正常小鼠大脑PrP^C和Aβ具有昼夜节律特征,快速眼动睡眠剥夺后PrP^C的表达水平下调,而Aβ表达水平上调,且这可能是睡眠剥夺后认知功能障碍的潜在机制之一。     

急性缺血性脑卒中后皮层及海马体积变化与认知功能的相关性研究

目的 探讨急性缺血性脑卒中后认知功能水平变化，并分析其影响因素。方法 纳入2020年2月-2022年6月收治入本院的86例急性缺血性脑卒中幸存者作为观察组，并选择34例无脑部疾病或创伤者作为对照组；急性缺血性脑卒中3个月与3年后比较2组患者一般资料、临床资料、全脑体积(Total brain volume, TBV)及海马体积(Hippocampus volume, HV)。结果 随访3个月时观察组与对照组高血压病的比例、Ⅱ型糖尿病的比例、发生房颤的比例、查尔森合并症指数(Charlson comorbidity index, CCI)、简易智能精神状态检查量表(Mini mental state examination, MMSE)评分以及HV比较有明显差异(P<0.05);认知功能正常组与认知功能受损组患者年龄、高血压病的比例、CCI,MMSE,TBV以及HV比较有明显差异(P<0.05),其余基础资料比较无明显差异(P>0.05)。随访3年后观察组与对照组患者房颤的比例、MMSE评分比较有明显差异；认知功能正常组与认知功能受损组年龄、高血压病的比例、CCI,MM...     

28h睡眠剥夺对脑内神经递质和脑功能的影响

目的 探索28 h睡眠剥夺对脑内神经递质的变化及脑功能的影响.方法 对9例健康被试在28 h睡眠剥夺前后进行脑电超慢涨落图检查,分析其在睡眠剥夺前后神经递质及脑功能的动态变化情况.结果 (1)被试在睡眠剥夺后脑内各种神经递质均有所变化,其中Glu、Ach和NE活动显著性减弱,GABA活动显著性增强,P均＜0.05;(2)被试在SD前后熵值均有一定的变化,其中O1和O2电极处在SD后熵值显著性增高,P均＜0.05;(3)被试缺血缺氧,疲劳状态程度在SD后均有加重.结论 脑电超慢涨落技术通过检测个体在28h睡眠剥夺前后的神经递质的动态变化,可以为脑力疲劳提供客观依据.     

Cerebral mitochondrial respiration in diabetic and chronically hypoglycemic rats

The respiratory function of cerebral mitochondria harvested from genetically diabetic (BB/W) and streptozotocin-diabetic rats deprived of insulin for 3-4 weeks was found to be unchanged from control values. Furthermore, insulin-deprived BB/W rats subjected to 30 min of insulin-induced hypoglycemic coma demonstrated a normal mitochondrial respiration following a 60 min period of glucose restitution, a finding consistent with earlier results in non-diabetic rats. However, in rats exposed to 1 week of moderate hypoglycemia (plasma glucose = 3.0 mumol.ml-1), both state 3 respiration and the respiratory control ratio (RCR) were reduced from control. In fact, when the chronic hypoglycemia was imposed following a 3-4 week period of diabetic hyperglycemia, the state 3 rate and RCR were found to be reduced to a greater degree than in chronically hypoglycemic, non-diabetic, previously normoglycemic rats. Finally, when 1 week of moderate hypoglycemia preceded a 30 min period of insulin-induced hypoglycemic coma, a disturbed pattern of mitochondrial respiration (i.e. increased state 4, decreased RCR) was found at 60 min of recovery following coma. These results indicate that chronic increases in glucose (and insulin deprivation) have no effect on cerebral mitochondrial respiratory function, whereas prolonged, albeit moderate, reductions in cerebral glucose supply result in perturbations in mitochondrial respiration. These results demonstrate the importance of an adequate glucose supply for normal mitochondrial activity.     

No evidence of brain cell degeneration after long-term sleep deprivation in rats

Sleep deprivation leads to cognitive impairments in humans and, if sustained for 2–3 weeks in rats, it is invariably fatal. It has been suggested that neural activity associated with waking, if it is not interrupted by periods of sleep, may damage brain cells through excitotoxic or oxidative mechanisms and eventually lead to cell death. To determine whether sustained waking causes brain cell degeneration, three parallel strategies were used. The presence and extent of DNA fragmentation was analyzed with the TUNEL technique on brain sections from rats sleep deprived for various periods of time (from 8 h to 14 days) and from their respective controls. Adjacent sections from the same animals were stained with a newly developed fluorochrome (Fluoro-Jade) specific for degenerating neurons. Finally, total RNA from the cerebral cortex of the same animals was used to determine whether the expression of several stress response genes and apoptosis-related genes is modified after sustained waking. In most long-term sleep deprived rats only a few scattered TUNEL positive nuclei (1–3) were found in any given brain section. The overall number, distribution, and morphology of TUNEL positive cells in long-term sleep deprived rats did not differ significantly from yoked controls, short-term sleep deprived rats, and sleep controls. No evidence of degenerating neurons as detected by Fluoro-Jade was found in any experimental group. mRNA levels of all the stress response genes and apoptosis-related genes tested did not differ between long-term sleep deprived rats and their yoked controls. These results argue against the hypothesis that sustained waking can significantly damage brain cells through excitotoxic or oxidative mechanisms and that massive cell death may explain the fatal consequences of sleep deprivation.     

The beneficial effects of regular exercise on cognition in REM sleep deprivation: behavioral, electrophysiological and molecular evidence

Inadequate sleep is prevalent in modern societies and is known to profoundly impair cognitive function. We examined the impact of 4 weeks of regular treadmill exercise on sleep deprivation induced spatial learning and memory, synaptic plasticity and related signaling molecules in area CA1 of the rat hippocampus. Rats were exercised on a treadmill and subsequently sleep-deprived for 24h using the modified multiple platform technique. Testing of learning and short-term memory performance in the radial arm water maze showed that although sedentary sleep deprived rats were severely impaired, exercised sleep deprived rats' performance was normal. Extracellular recording from area CA1 of anesthetized rats revealed that early phase LTP (E-LTP) was markedly impaired in the sedentary sleep deprived animals, but was normal in the exercised sleep deprived group. Additionally, immunoblot analysis of CA1 area before (basal) and after expression of E-LTP indicated that the significant down-regulation of the brain derived neurotrophic factor (BDNF) and phosphorylated calcium-calmodulin dependent protein kinase II (P-CaMKII) levels in sleep deprived animals was prevented by the regular exercise regimen. The results suggest that the regular exercise protocol prevents the sleep deprivation induced impairments in short-term memory and E-LTP by preventing deleterious changes in the basal and post-stimulation levels of P-CaMKII and BDNF associated with sleep deprivation.     

Impairment of mitochondrial respiration after cerebral hypoxia-ischemia in immature rats: relationship to activation of caspase-3 and neuronal injury

Mitochondrial damage may play a key role in the development of necrotic and apoptotic hypoxic-ischemic (HI) brain damage. It has previously been shown that mitochondrial respiration is depressed in the cerebral cortex after HI in neonatal animals. The aim of the present study was to further characterize the time course of the mitochondrial impairment during reperfusion and the correlation between the respiratory control ratio and brain injury and activation of caspase-3. Rat pups were subjected to unilateral carotid artery ligation and exposed to hypoxia (7.7% oxygen). Mitochondrial respiration was measured 0-72 h after HI in a mitochondrial fraction isolated from cerebral cortex. Microtubule associated protein-2 (MAP2) and caspase-3 were analyzed with immunoblotting in cerebral cortex homogenates. In addition, the time course of caspase-3 activation was measured as DEVD cleavage. The mitochondrial respiratory control ratio in cerebral cortex decreased immediately after HI followed by a partial recovery at 3-8 h. Thereafter, a secondary drop occurred with a minimum reached at 24 h of reperfusion. The secondary loss of respiratory function was accompanied by depletion of MAP2, cleavage of caspase-3 and an increased caspase-3 -like activity at 3-24 h after the insult. In conclusion, the primary phase of mitochondrial dysfunction was paralleled by a moderate decrease of MAP2 and a limited activation of caspase-3. The secondary mitochondrial impairment was associated with neuronal injury and pronounced activation of caspase-3.     

Sleep deprivation induced by the modified multiple platform technique: quantification of sleep loss and recovery

Vigilance status was continually monitored in socially stable groups of rats exposed to the modified multiple platform (MMP) technique for sleep deprivation. For comparison, sleep parameters were also monitored in socially isolated rats deprived of sleep by the single platform (SP) method. In all cases, sleep was continuously recorded during baseline, during 96 h of sleep deprivation and during 4 days of recovery. Both multiple- and single-platform techniques completely abolished paradoxical sleep (PS) during the deprivation period, but also resulted in significant decreases in slow wave sleep (SWS) (-31% and -37%, respectively). Unexpectedly, animals on large platforms, which are normally intended as controls, also showed significant reductions in PS and SWS, and these effects were more pronounced in rats deprived in groups than in animals deprived in isolation. Another control preparation, rats placed on wire-mesh grids in the deprivation tank, also showed PS reduction (-39%) but no loss of SWS during the 4 test days. Paradoxical sleep rebound was observed in the first 24 h in all groups, except for grid controls. Overall, no significant differences were found between single- and multiple-platform procedures during the 4 days of deprivation. However, sleep rebound was more pronounced in MMP-deprived rats than in SP-deprived rats. Sleep loss in both control groups may reflect residual effect of stress that remain in the platform technique. These findings indicate that the MMP technique is effective in inducing PS deprivation (PSD). However, the fact that SWS is also affected may have implications for conclusions on paradoxical sleep function based upon paradoxical sleep deprivation.     

Platform sleep deprivation affects deep slow wave sleep in addition to REM sleep

Rats were sleep deprived by the platform method to look for differential effects on light and deep slow wave sleep depending on platform size. Diameters of large and small platforms were 15 cm and 5.1 cm respectively. Sleep was recorded during a baseline light period (09.00-19.00 h), continuously during 48 h of sleep deprivation and during the first lights on recovery period (09.00-19.00 h). In both platform conditions REM sleep was virtually abolished during the first light period (hours 0-10 of sleep deprivation), while NREM sleep was reduced to approximately half of control values. During the second light period (hours 22-34 of sleep deprivation) REM sleep recovered somewhat in the large platform group. Light slow wave sleep (SWS-1) was comparable to baseline while deep slow wave sleep (SWS-2) was still significantly reduced. In the small platform group both SWS-2 and REM sleep was considerably reduced on day 2. Over the whole deprivation period there was an effect of platform size on SWS-1 (higher in the small platform group), and on SWS-2 and REM sleep (lower in the small platform group). During the 9 h light-time recovery sleep there was an REM sleep rebound in both groups. SWS-1 was reduced in both groups while SWS-2 was not significantly increased. The ratio SWS-2/SWS-1 was, however, significantly increased only in the small platform group recovery sleep. The results suggest that platform sleep deprivation deprives the animals of deep slow wave sleep in addition to REM sleep. This has implications for conclusions on REM sleep function based upon REM sleep deprivation.