ABSTRACT
Objective To observe the changes on the neurogenic inflammation-related factors in the dura mater of the rat model of migraine and investigate the possible mechanism of the pain of migraine.Methods SD rats were randomly divided into stimulation group ( n = 32 ) and sham group ( n = 32 ).Unilateral trigeminal ganglion was stimulated to induce migraine for rats in the stimulation group. Rats in the sham group were subjected to sham surgery. The levels of calcitonin gene-related peptide (CGRP) in the blood of jugular vein in the stimulation side were measured by radioimmunoassay. The levels of histamine in peripheral blood and prostaglandin E2 (PGE2 ) in the dura mater were determined by enzyme-linked immunosorbent assay (ELISA). The number of mast cells and percentage of their degranulation in the dura mater were determined under a microscope after toluidine blue staining. Cyclooxygenase 2 (COX-2)expression in the dura mater was evaluated by immunohistochemical staining and western blot analysis. Results In the stimulation group, the level of CGRP in the ipsilateral jugular vein was (82. 84 ± 16. 24)pg/ml and in the sham group was (59. 20 ±11.66) pg/ml (t = -3.34, P ＜ 0. 05 ). The level of histamine in the ipsilateral jugular vein was ( 11.59 ± 1.20) ng/ml and in the sham group was (9. 87 ±0. 88) ng/ml (t = - 3. 27, P ＜ 0. 05). The number of mast cells in the dura mater decreased from 15.46 ± 2. 40 in the stimulation group to 11.63 ± 1.67 in the sham group ( t = 3.71, P ＜ 0. 05 ). Degranulation of mast cells in the dura mater significantly increased from 14. 09% ±4. 53% in the sham group to 29. 10% ±9. 39% in the stimulation group (t = - 4. 07, P ＜ 0. 05 ). The level of PGE2 in the stimulation group was ( 382. 30 ±20. 90) pg/ml and in the sham group was (80. 70 ± 10. 60) pg/ml (t = - 16. 674, P ＜0. 05). The number of COX-2 positive cells significantly increased from 42. 00 ± 18.40 in the sham group to 139.00 ±20. 50 in the stimulation group (t = -7. 994, P ＜0. 05). Also the COX-2 protein level was elevated from 19. 50 ±9. 20 in the sham group to 359. 20 ±21.90 in the stimulation group (t = -5. 190, P ＜0. 05). Conclusions Electrical stimulation on the unilateral trigeminal ganglion induces neurogenic inflammation in the dura mater. Changes on the neurogenic inflammation-related factors are probably the essential pathophysiological mechanism underlying the pain in migraine.