The Effect Of P2X7 Receptor In Trigeminal Ganglion Satellite Glia Of Acute Migraine Rat Model

ObjectiveWe established a rat model of acute migraine by intraperitoneal nitroglycerin(GTN).After intraperitoneal GTN,We used Western blot to investigated the expression of P2X7 receptor and c-fos in trigeminal ganglion. Immunofluorescent staining technique was used to demonstrate the expression of P2X7 receptors and glial fibrillary acidic protein(GFAP).At last, we investigated the effect of P2X7 receptor antagonist on the expression of c-fos and CGRP in spinal trigeminal nucleus,to explore whether P2X7 receptor is involve in the pathogenesis of migraine and the potential mechanism.Materials and methods1.Ten male rats were randomly assigned into two groups. One group was treated by intraperitoneal normal saline(NS,n=5,2ml/Kg),the other group was treated by intraperitoneal GTN( n = 5,10mg/Kg).Before treatment, the hindpaw withdrawal threshold was measured by Von Frey. Then the PWT was measured at 1h、2h and 4h after treatment in each group. At last, We used immunofluorescent staining technique to demonstrate the expression of P2X7 receptors and GFAP.2.Twenty male rats were randomly divided into four groups.Normal group: without any treatment(n=5).1h group:1h after intraperitoneal GTN(n=5,10mg/Kg).2h group:2h after intraperitoneal GTN(n=5,10mg/Kg).4h group:4h after intraperitoneal GTN(n=5,10mg/Kg).Western blot was used to investigated the expression of P2X7 receptor and c-fos in trigeminal ganglion.3. Twenty male rats were randomly divided into four groups.NS group:2h after intraperitoneal NS.GTN group: 2h after intraperitoneal GTN.GTN+NS group: 2h after intraperitoneal GTN+NS.GTN+BBG group: 2h after intraperitoneal GTN+BBG.Western blot was used to investigated the expression of CGRP and c-fos in spinal trigeminal nucleus.Result1.Afert intraperitoneal GTN, the PWT was reduced and was notable at 2h,The PWT of GTN group was also lower than NS group at 2h(p<0.05).2.Immunofluorescent staining technique was used to demonstrate the expression of P2X7 receptors and GFAP.The result showed that P2X7 receptor and GFAP were co-expressed in satellite cells.3.After intraperitoneal GTN, the expression of P2X7 receptor was reduced in trigeminal ganglion, whereas the expression of c-fos and CGRP was increased in spinal trigeminal nucleus. With the addition of BBG, c-fos and CGRP were increased more significant in spinal trigeminal nucleus(p<0.05). Conclusion1.P2X7 receptor and GFAP were co-expressed in satellite cells.2.After intraperitoneal GTN, the expression of P2X7 receptor was reduced in trigeminal ganglion, which may participate the pathogenesis of migraine.3.The P2X7 receptor antagonist BBG can increase the expression of c-fos and CGRP in spinal trigeminal nucleus, thus the P2X7 receptor in satellite cells may have antinociceptive role in migraine.