The Effect Of Astrocyte Neuroligin-2 On The Trigeminal Root Entry Zone Chronic Compression Injury Of Rats

ObjectiveTrigeminal neuralgia(TN)is a chronic oral and facial pain syndrome characterized by paroxysmal,shock-like pain.The pathogenesis of TN is not yet clear,and there is currently no effective intervention for the pathogenesis of TN.Neuroligin-2(NL2)is a type of cell adhesion molecule distributed in the nervous system that controls the shape and synapse of astrocytes.Astrocytes play an important role in the pathogenesis of TN,but the expression and function of NL2 in astrocytes in TN have not been studied.In this study,we first observed the expression of NL2 in astrocytes of rat trigeminal root entry zone(TREZ).In addition,we established TN animal model,analyzed the correlation between NL2 and TN pathogenesis.Furthermore,by silencing the expression of NL2 in vivo,the effect of NL2 on the occurrence and development of TN was discussed to provide a theoretical and scientific basis for TN target therapy.Methods1.A chronic trigeminal neuralgia animal model was established by chronically compressing TREZ area in rats.Adult male SD rats were randomly divided into 5groups: sham operation group,trigeminal nerve root compression TN group,TN +NL2-sh RNA group(TN + NL2-specific sh RNA),TN + Ctl-sh RNA group(TN +negative control sh RNA group),TN + PBS group(TN + drug solvent control group).Von Frey wire was used to determine the mechanical and mechanical pain threshold of rats before and after operation.2.Immunohistochemistry and Western blotting methods were used to detect astrocyte-specific markers glial fibrillary acidic protein(GFAP),NL2 protein,and EGFP in rat TREZ at 7,14,21,and 28 days after surgery.The expression situation and change trend in the district.3.Primary astrocytes in the TREZ region of the TN animal model were cultured.Using GFAP immunohistochemical staining and DAPI for nuclear counterstaining,the purity of primary cultured astrocytes was counted.4.The NL2-sh RNA interference lentiviral vector was constructed to stably silence NL2 in astrocytes in the TREZ region of rats.5.The change of mechanical pain threshold analyzed in TN2 silenced TN animal model,to explore the effect of NL2 on the pathogenesis of TN.Results1.Compared with sham operation,rats in the TN group were sensitive to mechanical pain from 14 to 28 days after surgery(p <0.05).2.In the TN group,GFAP immunopositive astrocytes in the TREZ region of rats increased significantly.NL2 immunopositive co-localized with GFAP,and the protein expression level was consistent with GFAP.3.The result of primary culture of astrocytes in TREZ area showed that the purity of astrocytes was above 95%.4.Construction and identification of rat NL2-sh RNA interference lentiviral vector.5.After shRNA interference in the TN group,the threshold of oral and mechanical pain increased(p <0.05).ConclusionsIn the TN rat model,astrocytes in the TREZ region are activated and astrocyte NL2 expression increases after trigeminal nerve chronic compression injury.Local blocking of NL2 expression in the TREZ region up-regulate the oro-facial mechanical pain threshold in the TN group.Our results suggests that astrocyte NL2 activation was involved in the progress of peripheral hypersensitivity in the TN animal model of rats.