论文部分内容阅读
目的探讨地塞米松对脓毒症相关性脑病(SAE)大鼠海马区星形胶质细胞哺乳动物雷帕霉素靶蛋白(m TOR)表达的影响。方法 90只30日龄健康雄性Wistar大鼠被随机分为假手术组(10只)和盲肠结扎穿孔术(CLP)组(80只)。CLP组采用CLP建立脓毒症大鼠模型。CLP后12 h时如大鼠出现神经行为学评分降低、脑电图和体感诱发电位(SEP)异常,则诊断为SAE。再将SAE大鼠随机分为脑病未治疗组和地塞米松组。地塞米松组行尾静脉注射地塞米松(1 mg/kg),隔天1次,共3次;脑病未治疗组注射同剂量的生理盐水。大鼠40日龄时再次行神经行为学评分、脑电图和SEP检查,然后统一处死大鼠,取大鼠海马组织,蛋白质印迹法检测海马区神经细胞m TOR蛋白的表达,免疫荧光检测海马区星形胶质细胞胶质纤维酸性蛋白(GFAP)和m TOR的表达,图像分析系统软件统计阳性表达的细胞数量。结果 80只CLP大鼠在术后12 h内死亡6只,CLP后12 h时检查发现存活74只大鼠中有28只出现神经行为学评分降低,脑电图和SEP异常,诊断为SAE,其发病率为37.84%(28/74)。大鼠40日龄时,与脑病未治疗组比较,地塞米松组大鼠神经行为学评分降低,脑电图的α波明显减少、δ波增加,SEP的P1振幅下降、P1和N1潜伏期延长(P<0.05)。GFAP免疫荧光染色提示:假手术组大鼠海马区星形胶质细胞胞体小,突起细;而脑病未治疗组星形胶质细胞胞体和突起肥大,与假手术组比较,细胞数量明显增多(P<0.05);与脑病未治疗组比较,地塞米松组星形胶质细胞胞体小,突起细,细胞数量也明显减少(P<0.05)。与假手术组比较,脑病未治疗组表达m TOR的星形胶质细胞数量明显增多(P<0.05),与脑病未治疗组比较,地塞米松组表达m TOR的星形胶质细胞数量明显减少(P<0.05)。结论 SAE时大鼠海马区星形胶质细胞被激活,存在反应性增生,m TOR表达上调,而地塞米松对其具有抑制作用。
Objective To investigate the effect of dexamethasone on the expression of rapamycin target protein (m TOR) in astrocyte mammalian cells in the hippocampus of septic-encephalopathy (SAE) rats. Methods Ninety healthy male Wistar rats aged 30 days were randomly divided into sham operation group (n = 10) and cecal ligation and puncture (CLP) group (n = 80). CLP group was established by CLP CLP model of sepsis. Serum SAE was diagnosed at 12 h after CLP as evidenced by decreased neurobehavioral scores, abnormal EEG and somatosensory evoked potentials (SEP). Then SAE rats were randomly divided into encephalopathy untreated group and dexamethasone group. Dexamethasone group tail vein injection of dexamethasone (1 mg / kg), another day, a total of 3 times; encephalopathy untreated group with the same dose of saline. At 40 days of age, neurobehavioral score, electroencephalogram and SEP were performed again. Rats were sacrificed at the same time. The expression of mTOR protein in hippocampal neurons was detected by Western blotting. The expression of hippocampus Astrocyte glial fibrillary acidic protein (GFAP) and mTOR expression, image analysis system software to count the number of positive cells. Results Eighty CLP rats died within 12 h after operation. Neurological deficit score, EEG and SEP abnormalities were found in 28 of 74 surviving rats at 12 h after CLP. The EEG and SEP were diagnosed as SAE, The incidence rate was 37.84% (28/74). On the 40th day of age, compared with the untreated group, the neurobehavioral scores of dexamethasone group were decreased, the α wave of EEG was decreased, the δ wave was increased, the amplitude of P1 of SEP was decreased and the latency of P1 and N1 were prolonged (P <0.05). GFAP immunofluorescence staining showed that astrocytes in the sham operation group had small somatic cell bodies and prominent processes; while astrocytes in the sham-operated group did not have significant enlargement of the astrocyte cytoplasm and protrusions, compared with the sham-operated group, P <0.05). Compared with the untreated encephalopathy group, the number of astrocytes in the dexamethasone group was small, and the number of the cells was significantly decreased (P <0.05). Compared with the sham-operation group, the number of mTOR-expressing astrocytes in encephalopathy untreated group was significantly increased (P <0.05). Compared with the untreated group, the number of mTOR-expressing astrocytes was significantly lower in the dexamethasone group Decrease (P <0.05). Conclusion Astrocytes in the hippocampus of SAE rats are activated, with reactive hyperplasia and up-regulation of m TOR, while dexamethasone can inhibit it.