The Expression Of TRPV1in Dural And Trigeminal Ganglion Of Awake Recurrent Headache Rats

Object:The model of recurrent headache with peripheral sensitization in awake rats wasestablished by using inflammatory soup to activate dural nociceptors around superiorsagittal sinus, changes of periorbital pressure thresholds and the behaviour wereobserved, the expressions of TRPV1were detected during the process of peripheralsensitization and its mechanisms were explored in migraine rat model.Methods：Sixty healthy adult male Sprague-Dawley (SD) rats were randomly divided intofour groups (n=15):once IS infusion group (IS1d, B)、three times IS infusionsgroup(IS3d, C) six times IS infusions group (IS6, D) and six physiological saline(NS,A) infusions group.1,PE-10hoses were embedded upon the dura mater of the SD rat, then,rats weregiven compound proinflammatory agent with Hamilton micro-syringe via PE-10hosefor six days in a relatively fixed time (inflammatory soup of the IS)20ul or saline20ul.2, Von Frey monofilaments were applied to induce the pain behavior after eachinfusion for one hour and the periorbital pressure thresholds were determined.3, The dura mater and trigeminal ganglion were collected from catheterized ratsafter1.5hours of last infusion and PBS (Phosphate Buffered Saline) for western blotand real-time reverse transcription polymerase chain reaction and the expression ofTRPV1protein and mRNA were observed in dura mater and trigeminal ganglia. 4,TRPV1positive cells around the trigeminal ganglia were detected and countedusing a polyclonal rabbit antibody to TRPV1after1.5hours of last infusion.Result:1. The rats with the treatment of saline appeared behavior performance like shrinkinghead, without the behaviors such as sound, confining cage spinning, climbing cage,irritability. After one hour, Von Frey monofilaments were applied to test theperiorbital pressure thresholds, the results indicated that pressure thresholds weredecreased in the groups(IS1d、IS3d、IS6d) compared to the grop (NS), the eriorbitalpressure thresholds decreased gradually with the increased stimulating times,from the13g to4g,ther is statistics Significance between the group IS1d and group IS6d, butthere is no Significant difference within groups.2. Immunofluorescence staining showed visible TRPV1protein expressed in neuronalcell membrane and cytoplasm in trigeminal ganglion in all groups3. There is TRPV1expression in dural and trigeminal ganglion of each group.Compared with the control group, the expression of TRPV1protein and mRNA indura and trigeminal ganglion of experimental groups were significantly increased andthe expression of group D was the highest, the difference has statistically significance(P <0.05);Conclusion:Repeated episodes of headache can be successfully induced by given the ISthrough the PE-10hose embeddedupon the dura mater several times. IS infusionrepeatly can lead to rat periorbital pain threshold decreased and the phenomenon ofsensitization. The increased TRPV1expression maybe an important mechanism onthe peripheral sensitization in migraine. TRPV1is involved in the occurrence ofmigraine development and the peripheral sensitization formation. The amount ofTRPV1protein and mRNA upregulated during this period with headache increasing frequency. IS caused pain peripheral sensitization forming from gene transcriptionlevel of TRPV1protein. TRPV1protein expression in trigeminal ganglion and duramater upregulation may be one of the important mechanisms in migraine peripheralsensitization.