The present study investigated the effects of circadian rhythm disorder (CRD) on the hippocampus of SHR and WKY rats. Male SHR rats (n = 27) and WKY rats (n = 27) were randomly divided into six groups: SHR and WKY normal (N)CR, SHR and WKY CRD 16/8 (CRD16/8), and SHR and WKY CRD 12/12 (CRD12/12). Activity patterns were adjusted using different photoperiods over 90 days and any changes were recorded. Rats were tested in the Morris water maze and in a novel object recognition experiment; serologic analysis, magnetic resonance imaging (diffusion tensor imaging + arterial spin labeling), hippocampal Nissl staining, Fluoro-Jade B staining, and immunohistochemistry were also performed. The results showed that both types of inverted photoperiod reduced CR amplitude and prolonged the circadian period. CRD and hypertension reduced memory performance and novel object recognition and preference. The decreases in memory and preference indices were greater in rats in the CRD12/12 group compared to the CRD16/8 group. CRD and hypertension decreased fractional anisotropy values, the number of neurons and astrocytes in the hippocampus, and the expression of brain-derived neurotrophic factor and synapsin 1; it also enhanced the degeneration of neurons and microglia and reduced blood flow in the hippocampus, and increased nuclear factor κB, caspase, neuron-specific enolase, and interleukin-6 levels. These findings reveal a biological basis for the link between CRD and cognitive decline, which has implications for CRD caused by shift work and other factors.

中文翻译：

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昼夜节律紊乱对SHR和WKY大鼠海马的影响。

本研究调查了昼夜节律障碍（CRD）对SHR和WKY大鼠海马的影响。将雄性SHR大鼠（n = 27）和WKY大鼠（n = 27）随机分为六组：SHR和WKY正常（N）CR，SHR和WKY CRD 16/8（CRD16 / 8），以及SHR和WKY CRD 12/12（CRD12 / 12）。在90天内使用不同的光周期调整了活动模式，并记录了任何变化。在莫里斯水迷宫和新颖的物体识别实验中对大鼠进行了测试；还进行了血清学分析，磁共振成像（扩散张量成像+动脉旋转标记），海马Nissl染色，Fluoro-Jade B染色和免疫组织化学。结果表明，两种类型的倒置光周期均会降低CR幅度并延长昼夜周期。CRD和高血压会降低记忆力，并降低新物体的识别和偏好。与CRD16 / 8组相比，CRD12 / 12组的大鼠记忆力和偏好指数的下降更大。CRD和高血压降低了分数各向异性值，海马中神经元和星形胶质细胞的数量以及脑源性神经营养因子和突触蛋白1的表达；它也增强了神经元和小胶质细胞的变性，减少了海马的血流量，并增加了核因子κB，胱天蛋白酶，神经元特异性烯醇化酶和白介素6的水平。这些发现揭示了CRD与认知能力下降之间联系的生物学基础，这对轮班工作和其他因素导致的CRD产生了影响。与CRD16 / 8组相比，CRD12 / 12组的大鼠记忆力和偏好指数的下降更大。CRD和高血压降低了分数各向异性值，海马中神经元和星形胶质细胞的数量以及脑源性神经营养因子和突触蛋白1的表达；它也促进了神经元和小胶质细胞的变性，减少了海马的血流量，并增加了核因子κB，胱天蛋白酶，神经元特异性烯醇化酶和白介素6的水平。这些发现揭示了CRD与认知能力下降之间联系的生物学基础，这对轮班工作和其他因素导致的CRD产生了影响。与CRD16 / 8组相比，CRD12 / 12组的大鼠记忆力和偏好指数的下降更大。CRD和高血压降低了分数各向异性值，海马中神经元和星形胶质细胞的数量以及脑源性神经营养因子和突触蛋白1的表达；它也增强了神经元和小胶质细胞的变性，减少了海马的血流量，并增加了核因子κB，胱天蛋白酶，神经元特异性烯醇化酶和白介素6的水平。这些发现揭示了CRD与认知能力下降之间联系的生物学基础，这对轮班工作和其他因素导致的CRD产生了影响。脑源性神经营养因子和突触蛋白1的表达；它也增强了神经元和小胶质细胞的变性，减少了海马的血流量，并增加了核因子κB，胱天蛋白酶，神经元特异性烯醇化酶和白介素6的水平。这些发现揭示了CRD与认知能力下降之间联系的生物学基础，这对轮班工作和其他因素导致的CRD产生了影响。脑源性神经营养因子和突触蛋白1的表达；它也增强了神经元和小胶质细胞的变性，减少了海马的血流量，并增加了核因子κB，胱天蛋白酶，神经元特异性烯醇化酶和白介素6的水平。这些发现揭示了CRD与认知能力下降之间联系的生物学基础，这对轮班工作和其他因素导致的CRD产生了影响。