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Objective Apply modified bilateral carotid artery ligation to establish a VD rat model to observe changes in cerebral blood flow and expression of angiogenic proteins.Methods Thirty-six SD male rats were randomly divided into a sham group(n = 18)and model group(n = 18).In the sham group,only the bilateral carotid artery was isolated without ligation,whereas in the model group,the bilateral carotid artery was ligated to establish the VD model.The Morris water maze behavior test was applied before and 14 days after modeling.Variation in cerebral blood flow was detected by laser speckle contrast imaging.Protein expression of HIF-1α,VEGF,and HO-1 was detected by Western Blot.IL-4 and IL-10 contents were measured by ELISA.Results At 14 days after modeling,escape latency was significantly prolonged and the frequency of crossing the platform had significantly decreased in the model group compared with the sham group(P<0.05).At 2 hours,3 days,and 7 days after modeling,cerebral blood flow in the model group was significantly lower than that in the sham group(P<0.05).At 14 and 21 days after modeling,no significant difference was found in cerebral blood flow between sham and model groups(P>0.05).In the model group,cerebral blood flow was decreased to a minimum at 2 hours after modeling(P<0.05)and then began to recover.The peak of recovery occurred at 3～7 days after modeling and returned to the level before modeling on day 14 after modeling.At postoperative day 21,expression of HIF-1α,VEGF,and HO-1 proteins in the hippocampus of the model group was increased remarkably(P<0.05)and the serum contents of IL-4 and IL-10 in the model group were significantly increased compared with those in the sham group(P<0.05).Conclusions The variation in cerebral blood flow in the VD rat model established by the modified bilateral carotid artery ligation was dependent on time.At postoperative day 21,HIF-1α,VEGF,and HO-1 in the hippocampus were increased significantly,which was accompanied by increased levels of IL-4 and IL-10.
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Objective:To evaluate the role of silent information regulator 1 (SIRT1)/nuclear factor E2 related factor 2 (Nrf2) signaling pathway in sleep deprivation-induced cognitive dysfunction in rats.Methods:Thirty-six adult male Sprague-Dawley rats, aged 54-56 weeks, weighing 600-750 g, were divided into 3 groups ( n=12 each) using a random number table method: control group (group C), sleep deprivation group (group SD) and sleep deprivation+ SIRT1 agonist Srt1720 group (group SD+ Srt). Sleep deprivation model was established by modified multi-platform water environment method.Srt1720 10 mg/kg was injected intraperitoneally every 12 h starting from 24 h before establishing the model in group SD+ Srt, while the equal volume of 0.9% normal saline was injected intraperitoneally in C and SD groups.After the end of sleep deprivation, Morris water maze test was performed to evaluate the cognitive function.Animals were then sacrificed, and their hippocampi were removed for determination of neuronal degeneration rate in hippocampal CA1 region (using HE staining), the apoptosis rate in hippocampal CA1 (using TUNEL assay ), the expression of SIRT1 and Nrf2 in hippocampal CA1 (by immunohistochemistry) and the contents of reactive oxygen species (ROS) and superoxide dismutase (SOD) (by microplate method). Results:Compared with group C, the escape latency was significantly prolonged, the time of staying at the platform quadrant was shortened, and the frequency of crossing the platform was decreased on 2-4 days, the apoptotic rate and neuronal degeneration rate were increased, the expression of SIRT1 and Nrf2 was down-regulated, ROC content was increased, and SOD content was decreased in SD and SD+ Srt groups ( P<0.05). Compared with group SD, the escape latency was significantly shortened, the time of staying at the platform quadrant was prolonged, and the frequency of crossing the platform was increased on 3 and 4 days, the apoptotic rate and neuronal degeneration rate were decreased, the expression of SIRT1 and Nrf2 was up-regulated, ROC content was decreased, and SOD content was increased in group SD+ Srt ( P<0.05). Conclusions:Sleep deprivation can induce oxidative stress response in hippocampus by inhibiting the activation of SIRT1/Nrf2 signaling pathway, leading to cognitive dysfunction in rats.