| Objective To explore the expression and role of NLRP3 inflammasome in spinal cord of chronic constriction injury rats and study the mechanism that glial cells and neurons promote the development of neuropathic pain by NLRP3 inflammasome.Methods Thirty-six male SD rats were randomly divided into 4 groups(n=9): Sham operation group(control group),chronic constriction injury group(CCI group),solvent group(CCI-vehicle group)and inhibitor group(CCI-MCC950 group).Pain behavior and mechanical pain threshold(MWT)was assessed on 1d before operation and the 1、4 and 7d after CCI operation.Rats in CCI-vehicle group were intrathecally injected with MCC950 10ul(1mg/mg)followed by 10 ul normal saline from day 4 to day 6 after surgery,while rats in CCI-vehicle group received equal volume of normal saline.After measurement of behavior and MWT on 7d after surgery,animals were sacrificed and the lumbar spinal cord(L4-6)was obtained.The protein and m RNA expressions of NLRP3,ASC,caspase-1 and IL-1β were detected by Western blotting and RT-PCR.Immunofluorescent double labeling was performed to identify the cell types of NLRP3-inflammasome’s expression.TUNEL staining was performed to detect cell apoptosis.Results Compared with control group,rats in CCI group,CCI-vehicle group and CCI-MCC950 group behaved limp,toe deformity,licking,biting and autophagy after surgery,the MWT was significantly decreased after operation(P<0.05),the protein and m RNA expressions of NLRP3,ASC,caspase-1 and IL-1β were obviously increased(P<0.05)and the level of apoptotic cells were up-regulated strikingly(P<0.05).Compared with CCI group and CCI-vehicle group,MWT was significantly up-regulated in CCI-MCC950 group on 7 d after surgery(P<0.05),the protein and m RNA expressions of NLRP3,ASC,caspase-1 and IL-1β were partly decreased(P<0.05)and the level of apoptotic cells were down-regulated(P<0.05).NLPR3 is mainly expressed in the cytoplasm of spinal dorsal horn astrocytes and neurons.Conclusion NLRP3 inflammasome has been activated in spinal cord of chronic constriction injury rats,and it may play a crucial role in promoting the development of neuropathic pain,which may be involved in neuroinflammation and apoptosis resulted by NLRP3 inflammasom. |
