The Study Of Pathogenesis Of Trigeminal Neuralgia Induced By Chronic Compression Of The Trigeminal Nerve Root

Objective: To observe the morphological changes of glial cells and expression of Fyn and myelin injury in the trigeminal neuralgia?TN?animal model of rats induced by chronic compression of the trigeminal nerve root?CCT?,according to the observation of orofacial pain threshold,combined with the immunofluorescence,Western blot and electron microscopy techniques.Methods:?1?The TN animal model of rats was built by CCT as the SD male rats for the experimental subjects,and the orofacial mechanical allodynia of the rats was assessed with von Frey filament on day of-1,1,3,5,7,14,21 and 28 after operation.?2?To explore the pathological changes of the astrocytes,oligodendrocytes,schwann cells and microglia in the TREZ after the CCT surgery,according to the expression of the kinds of GFAP,IBA-1,MBP and P75^NTR by using the immunofluorescence techniques.?3?To explore the pathological changes in the TREZ by use of the transmission electron microscopy technique,and the correlations were discussed in combination with immunofluorescence and the behavior of rats.?4?To observe the Fyn protein expression after the CCT surgery by use of the immunofluorescence and western blot techniques,together with the changes of glial cells to study the correlation in the process of the damage and regeneration.Results:?1?Behavioral test showed that the threshold of orofacial mechanical allodynia of the CCT TN group rats significantly reduced from day 14 after operation,compared with the sham group?P < 0.05?.?2?The immunohistochemistry for GFAP,IBA-1,MBP and P75^NTR showed that the immunoreactive protein was changed and migrated in the TREZ.We showed that the up-regulation of IBA-1 and P75^NTR positive cells in the TREZ area on post-operation day 7,and the IBA-1 positive cell in the CNS area was reduced;the fluorescence intensity of the P75^NTR and IBA-1 positive cells is reduced on post-operation day 14,while significantly higher than the sham group;we observed that there was no obvious difference between 21 days with 28 days after CCT for the expression of IBA-1 and p75 NTR protein,and however,the fluorescence intensity of MBP increasing on the 21 days after CCT,until the mature oligodendrocytes marked with MBP form the fornix shape boundary as the same with marker of GFAP in the border area on the 28 days after CCT.?3?The transmission electron microscopy for the TREZ showed that degenerative and demyelination of the fibers;there were the loose of myelin sheath and the amounts of vacuoles in the myelin cells.?4?Western blot and the immunohistochemistry showed that the Fyn expression in TN group,which reduced from day 7 after CCT operation?P < 0.05?,and the lowest level on post-operation day 14,up-regulated on post-operation day 21 and lasted for day 28;however,there were no changes for the Fyn of the sham group?P < 0.05?.Conclusions:?1?The change of schwann cells,astrocytes,oligodendrocytes and microglia influenced each other,while involved in the process of damage and regeneration.?2?The expression of Fyn was reduced in the early phase of TN animal model after CCT,and increased in the late phase of TN animal model,which suggested that the Fyn may participate in the pathogenetic process of the TN animal model.?3?The change of the glial cells plays an important role in the pathogenesis of TN induced by chronic compression of the trigeminal nerve root.