ABSTRACT
Objective To investigate the effects of acetylated HMGB1 on cognitive function in rats with sepsis associated encephalopathy (SAE) and the effect of HMGB1 inhibitor.Methods Forty-eight males mice were randomly assigned to three groups (n=16): sham group (group S),cecal ligation puncture group (group C),cecal ligation puncture+sodium butyrate group (group B).Cecal ligation puncture was applied to establish the SAE model,and group S received sham operation.Rats in groups S and C were injected with normal saline 5 ml/kg 30 min and 4 h after CLP,respectively.The rats in group B were intraperitoneally injected with sodium butyrate 500 mg/kg 0.5 h and 4 h after CLP,respectively.All animals were performed Morris water maze test on 4th day after operation,and the exploring time of space exploration experiments were assessed on 7th day after CLP surgery.IL-6,BDNF,HMGB1 and acetylated HMGB1 expression in hippocampus of all rats were determined by Western Blot.Results Compared with group S,the latency of rats in group C was longer and the exploring time was shorter (P<0.05).Compared with group C,the latency of rats in group B was shorter and the exploring time was longer (P<0.05).Compared with group S,the expression of IL-6,HMGB1 and acetylated HMGB1 in group C increased (P<0.05) and the level of BDNF decreased (P<0.05).Compared with group C,the expression of IL-6,HMGB1 and acetylated HMGB1 in group B decreased (P<0.05) and the level of BDNF increased (P<0.05).Conclusion HMGB1 inhibitor sodium butyrate can inhibit the expression of acetylated HMGB1 in the hippocampus of SAE rats,and reduce the cognitive impairment induced by sepsis.
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Objective To investigate the role of hippocampal cyclophilin D (CypD) in sepsis-associated encephalopathy in rats.Methods A total of 36 adult male Sprague-Dawley rats,aged 3-4 months,weighing 300-400 g,were randomly divided into 3 groups (n =12 each) using a random number table:sham operation group (Sham group),sepsis group (S group),and sepsis + CypD inhibitor cyclosporin A group (CsA group).Sepsis was induced by cecal ligation and puncture (CLP).Cyclosporin A 6 mg/kg was injected intraperitoneally at 30 min before CLP in group CsA.All the animals underwent Morris water maze test on 4th day after CLP.The animals were sacrificed after the test,and the hippocampus was isolated for determination of the expression of cytochrome c (Cyt c),CypD,caspase-3,brain-derived neurotrophic factor (BDNF),phosphorylated protein kinase A (p-PKA),and phosphorylated cyclic adenosine monophosphate response element-binding protein (p-CREB).Results Compared with group Sham,the escape latency was significantly prolonged,the space exploration time was shortened,the expression of Cyt c,CypD,caspase-3,p-PKA and p-CREB was up-regulated,and the expression of BDNF was down-regulated in S and CsA groups (P＜0.05).Compared with group S,the escape latency was significantly shortened,the space exploration time was prolonged,the expression of Cyt c,CypD,caspase-3,p-PKA and p-CREB was down-regulated,and the expression of BDNF was up-regulated in group CsA (P＜0.05).Conclusion Hippocampal CypD may be involved in the pathophysiological mechanism of sepsis-associated encephalopathy,and the downstream mechanism is probably related to promotion of activation of PKA/CREB signaling pathway in rats.
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Objective To evaluate the effect of exogeneous adiponectin on hippocampal advanced glycation end products (AGEs)-reactive oxygen species (ROS)-endoplasmic reticulum stress (ERS) pathway in aged mice with postoperative cognitive dysfunction (POCD).Methods Thirty-two healthy male C57BL/6 mice, aged 18 months, weighing 20-25 g, were randomly divided into 4 groups (n=8 each) using a random number table: control group (group C), POCD group, exogeneous adiponectin group (group APN), and vehicle group (group Veh).Splenectomy was performed to establish the POCD model in aged mice anesthetized with intraperitoneal pentobarbital sodium.In group APN, adiponectin 0.1 μg/g (in 2 μl of phosphate buffer solution) was injected into the lateral cerebral ventricle at 30 min before establishing the model.Phosphate buffer solution 2 μl was given at 30 min before establishing the model in group Veh.Cognitive function was assessed on day 7 after surgery.The mice were then sacrificed, and the hippocampus was harvested for determination of the area of AGE deposition (by immunohistochemistry), levels of ROS (by flow cytometry), and levels of glucose-regulated protein 78 (GRP78), C/EBP-homologous protein (CHOP), caspase-12 and ROS (using Western blot).Results Compared with group S, the freezing time in the contextual fear conditioning test was significantly shortened, the area of AGE deposition and levels of ROS, CHOP and caspase-12 were increased, and the level of GRP78 was decreased in POCD, APN and Veh groups.Compared with POCD and Veh groups, the freezing time in the contextual fear conditioning test was significantly prolonged, the area of AGE deposition and levels of ROS, CHOP and caspase-12 were decreased, and the level of GRP78 was increased in group APN.Conclusion Exogeneous adiponectin decreases the occurrence of POCD probably by blocking hippocampal AGEs-ROS-ERS pathway in aged mice.