Role of autophagy in electroacupuncture-induced improvement in sepsis-associated encephalopathy in mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of autophagy in electroacupuncture (EA)-induced improvement in sepsis-associated encephalopathy (SAE) in mice.Methods:A total of 135 healthy adult male mice, aged 8-12 weeks, weighing 22-25 g, were used in this study. Ten mice were randomly selected to prepare caecal slurry after anesthesia. The remaining 125 mice were divided into 5 groups ( n=25 each) using a random number table method: sham operation group (group Sham), SAE group, SAE+ EA group (group EA), SEA+ EA+ autophagy agonist rapamycin group (group SAE+ EA+ R), and SAE+ EA+ autophagy inhibitor 3-methyladenine group (group SAE+ EA+ MA). SAE was induced by intraperitoneal injection of cecal slurry 200 μl. Bilateral Zusanli (ST36) acupoints were stimulated at 2, 24, 48 and 72 h after surgery in group SAE+ EA, group SAE+ EA+ R and group SAE+ EA+ MA. Autophagy agonist rapamycin 10 mg/kg and autophagy inhibitor 3-methyladenine 15 mg/kg were intraperitoneally injected at 30 min before EA in SAE+ EA+ R group and SAE+ EA+ MA group, respectively. The survival of mice was recorded at 7 days after developing the model. Ten mice were selected from each group at 8-12 days after developing the model, and the learning and memory ability was assessed by Morris water maze test. Five mice from each group were sacrificed after anesthesia, brains were removed, and hippocampal tissues were obtained for determination of contents of interleukin-1beta (IL-1β), IL-18 and tumor necrosis factor-α (TNF-α) (by enzyme-linked immunosorbent assay) and expression of p62, autophagy-related protein 16 like protein 1 (ATG16L1), and nucleotide like receptor protein 3 (NLRP3) (by Western blot). Results:Compared with Sham group, the survival rate at 7 days after developing the model was significantly decreased in the other 4 groups ( P<0.01). There was no significant difference in the survival rate at 7 days after developing the model among SAE group, SAE+ EA group, SAE+ EA+ R group and SAE+ EA+ MA group ( P>0.05). Compared with Sham group, the activity time at the target quadrant was significantly shortened, the escape latency was prolonged, the number of crossing the original platform was reduced, the contents of TNF-α, IL-1β and IL-18 were increased, the expression of ATG16L1 was down-regulated, and the expression of p62 and NLRP3 was up-regulated in SAE group ( P<0.05). Compared with SAE group, the escape latency was significantly shortened, the activity time at the target quadrant was prolonged, the number of crossing the original platform was increased, the contents of TNF-α, IL-1β and IL-18 were decreased, the expression of ATG16L1 was up-regulated, and the expression of p62 and NLRP3 was down-regulated in SAE+ EA group ( P<0.05). Compared with SAE+ EA group, no significant change was found in the parameters of Morris water maze test ( P>0.05), the contents of TNF-α, IL-1β and IL-18 were significantly decreased, the expression of ATG16L1 was up-regulated, and the expression of NLRP3 and P62 was down-regulated in SAE+ EA+ R group, and the expression of ATG16L1 was significantly down-regulated, and the expression of p62 and NLRP3 was up-regulated in SAE+ EA+ MA group ( P<0.05). Conclusions:The mechanism by which EA improves SAE is related to promotion of autophagy in hippocampal neurons, inhibition of NLRP3 inflammasome activation, and alleviation of neuroinflammatory responses in mice.