Li Yafei, Su Yunjie, Qu Yi, Mu Dezhi, Li Xihong
Pediatric Intensive Care Unit, West China Second University Hospital, Sichuan University, Chengdu 610041, China.
Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2016 Jun 28;41(6):571-7. doi: 10.11817/j.issn.1672-7347.2016.06.004.
To show evidence of the autophagy in hippocampal nerve cells from rats with sepsis-associated encephalopathy (SAE) in vivo and to investigate the expression of microtubule-associated protein 1 light chain 3 (LC3).
A rat model of sepsis was established by the cecal ligation and puncture (CLP). A total of 60 male Wistar rats (30 days old) were randomly divided into a sham group (n=10) and a CLP group (n=50). At 12 hours after CLP, the electroencephalogram (EEG) and somatosensory evoked potential (SEP) changes in rats were monitored and the neurobehavioral score was measured. According to the occurrence of SAE, the CLP group was further divided into an SAE(+) group and an SAE(-) group. Histopathological changes in hippocampus were observed by hematoxylin-eosin staining. An electron microscope was used to observe autophagosome formation and lysosome activation in the hippocampal nerve cells. Expressions of LC3-I and LC3-II protein were measured by Western blot.
Five of 50 rats in CLP group died in 12 hours after CLP. According to the low neurobehavioral score and abnormal EEG and SEP, 16 rats were diagnosed as SAE. The incidence of SAE was 35.56% (16/45). Compared with the sham group or the SAE(-) group, the frequency of α wave in SAE(+) group was significantly decreased at 12 hours after CLP, the δ wave increased, the P1 amplitude decreased, and the latency of SEP waves (P1 and N1) was prolonged (P<0.05). The morphology of hippocampal nerve cells was obvious in a status of edema. Pyramidal cells decreased significantly, even dissolved, and cell arrangement was in disorder in the SAE(+) group. But these cells were normal in the sham group and the SAE(-) group. The structure of hippocampal nerve cells was disordered, and the autophagy, granular matrix and square or rectangular crystals were found in the SAE(+) group. However, there was no autophagy both in the sham group and the SAE(-) group. LC3-II/LC3-I ratio in the hippocampal nerve cells was increased significantly at 12 hours after CLP in the SAE(+) group when compared with that in the sham or the SAE(-) group (P<0.05).
There is autophagy in hippocampal nerve cells from rats with SAE and the LC3-II/LC3-I ratio is increased significantly.
在体内证实脓毒症相关性脑病（SAE）大鼠海马神经细胞存在自噬现象，并研究微管相关蛋白1轻链3（LC3）的表达情况。
采用盲肠结扎穿孔术（CLP）建立大鼠脓毒症模型。将60只30日龄雄性Wistar大鼠随机分为假手术组（n = 10）和CLP组（n = 50）。CLP术后12小时，监测大鼠脑电图（EEG）和体感诱发电位（SEP）变化，并测量神经行为学评分。根据SAE的发生情况，将CLP组进一步分为SAE(+)组和SAE(-)组。采用苏木精-伊红染色观察海马组织病理学变化。用电子显微镜观察海马神经细胞自噬体形成及溶酶体激活情况。采用蛋白质免疫印迹法检测LC3-I和LC3-II蛋白表达。
CLP组50只大鼠中有5只在CLP术后12小时死亡。根据低神经行为学评分及EEG和SEP异常，16只大鼠被诊断为SAE。SAE发生率为35.56%（16/45）。与假手术组或SAE(-)组相比，SAE(+)组在CLP术后12小时α波频率显著降低，δ波增加，P1波幅降低，SEP波（P1和N1）潜伏期延长（P<0.05）。SAE(+)组海马神经细胞形态呈明显水肿状态。锥体细胞显著减少，甚至溶解，细胞排列紊乱。而假手术组和SAE(-)组细胞正常。SAE(+)组海马神经细胞结构紊乱，可见自噬、颗粒状基质及方形或长方形晶体。然而，假手术组和SAE(-)组均未发现自噬现象。与假手术组或SAE(-)组相比，SAE(+)组在CLP术后12小时海马神经细胞中LC3-II/LC3-I比值显著升高（P<0.05）。
SAE大鼠海马神经细胞存在自噬现象，且LC3-II/LC3-I比值显著升高。
