Changes in expression of NLRP3 inflammasomes in spinal cord of rats with neuropathic pain / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the changes in the expression of NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasomes in the spinal cord of rats with neuropathic pain.Methods Fifty-four healthy adult male Sprague-Dawley rats,weighing 250-300 g,were divided into 2 groups (n=27 each) using a random number tablesham operation group (S group) and neuropathic pain group (NP group).Neuropathic pain was produced by chronic constriction injury in anesthetized rats.The sciatic nerve was exposed,and 4 loose ligatures were placed on the sciatic nerve at 1 mm intervals with 4.0 chromic catgut.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before operation and 1,4,7 and 14 days after operation.After measurement of MWT at each time point after operation,the animals were sacrificed,and the L4_6 segments of the spinal cord were removed for determination of the expression of NLRP3,apoptosis-associated speck-like protein containing a CARD (ASC),caspase-1 and interleukin-1beta (IL-1β) protein and mRNA (by Western blot or by fluorescent quantitative real-time polymerase chain reaction).After measurement of MWT at day 14 after operation,the L4-6 segments of the spinal cord were removed for determination of the co-expression of NLRP3 with glial fibrillary acidic protein (GFAP) (by double immunofluorescence staining).Results Compared with S group,the MWT was significantly decreased,and the expression of NLRP3,ASC,caspase-1 and IL-1β protein and mRNA was up-regulated at each time point after operation in NP group (P＜0.05).The expression of NLRP3 and ASC protein and mRNA peaked at day 4 after operation,the expression of caspase-1 and IL-1β protein and mR-NA peaked at day 7 after operation,and the MWT reached the lowest value at day 7 after operation (P＜0.05).NLPR3 inflammasomes were mainly expressed in the astrocytes and neurons.Conclusion The expression of NLPR3 inflammasomes in the spinal astrocytes and neurons is up-regulated in the rats with peripheral nerve damage,and the change may be involved in the development and maintenance of neuropathic pain.