Role of NLRP3 in sepsis-associated encephalopathy and the relationship with pyroptosis in microglia of mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) in sepsis-associated encephalopathy (SAE) and the relationship with pyroptosis in microglia of mice.Methods:Twenty-four SPF healthy male C57BL/6J mice, aged 6-8 weeks, weighing 18-22 g, were divided into 3 groups ( n=6 each) using a random number table method: sham operation group (Sham group), SAE group and SAE plus an NLRP3 inhibitor MCC950 group (SAE+ MCC950 group). The mouse model of SAE was prepared by cecal ligation and puncture after anesthesia. MCC950 20 mg/kg was intraperitoneally injected at 1 h after developing the model in SAE+ MCC950 group, and the equal volume of normal saline was given instead in the other groups. Open field tests were conducted at 1 day after developing the model to record the number of rearing and time spent in the central area. Novel object recognition tests were conducted at 2-3 days after developing the model to record the recognition index. After the behavioral experiment on 3 day after developing the model, mice were sacrificed and hippocampal tissues were collected for determination of the expression of NLRP3 (by Western blot), count of cells co-expressing NLRP3 and microglia-specific ionized calcium-binding adaptor molecule 1 (Iba-1) (by immunofluorescence), activity of caspase-1, and contents of interleukin-1beta(IL-1β) and IL-18 (by enzyme-linked immunosorbent assay). Results:Compared with Sham group, the number of rearing was significantly reduced, the time spent in the central area was shortened, the recognition index was decreased, the expression of NLRP3 was up-regulated, the count of NLRP3 + -Iba-1 + cells was increased, and the activity of caspase-1 and contents of IL-1β and IL-18 were increased in SAE and SAE+ MCC950 groups ( P<0.05). Compared with SAE group, the number of rearing was significantly increased, the time spent in the central area was prolonged, the recognition index was increased, the expression of NLRP3 was down-regulated, the count of NLRP3 + -Iba-1 + cells was decreased, and the activity of caspase-1 and contents of IL-1β and IL-18 were decreased in SAE+ MCC950 group ( P<0.05). Conclusions:NLRP3 is involved in the development of SAE, which may be related to the mediation in microglial pyroptosis in mice.