TY - JOUR
T1 - A novel trigeminal neuropathic pain model
T2 - Compression of the trigeminal nerve root produces prolonged nociception in rats
AU - Jeon, Hye J.
AU - Han, Seung R.
AU - Park, Min K.
AU - Yang, Kui Y.
AU - Bae, Yong C.
AU - Ahn, Dong K.
PY - 2012/8/7
Y1 - 2012/8/7
N2 - We demonstrate the establishment of a novel animal model for trigeminal neuropathic pain following compression of the trigeminal nerve root, which produces prolonged nociceptive behavior and demyelination of the trigeminal nerve root. Under anesthesia, male Sprague-Dawley rats (200-230. g) were mounted onto a stereotaxic frame and injections of a 4% agar solution (10 μl) were given to achieve compression of the trigeminal nerve root. A sham operation was performed using identical procedures but without agar injections. Nociceptive behavior was examined 3. days before and then at 3, 7, 10, 14, 17, 21, 24, 30, 40, 55, and 70. days after the surgery. Compression of the trigeminal nerve root caused mechanical allodynia, hyperalgesia, and cold hypersensitivity. Mechanical allodynia was established within 3. days and recovered to preoperative levels on postoperative day (POD) 40. Mechanical hyperalgesia and cold hypersensitivity persisted until 55. days following compression. The compression produced focal demyelination in the trigeminal nerve root. In the medullary dorsal horn, phospho-p38 (p-p38) mitogen-activated protein kinase (MAPK) was found to be exclusively expressed in the microglia on POD 14. Furthermore, intraperitoneal administration of carbamazepine (50. mg/kg) significantly blocked mechanical allodynia and reduced p38 MAPK activation induced by the compression of the trigeminal nerve root. Our findings suggest that prolonged nociceptive behavior following compression of the trigeminal nerve root may mimic trigeminal neuralgia in this animal model and that the activation of p38 MAPK in the microglia contributes to pain hypersensitivity in rats that have undergone compression of the trigeminal nerve root.
AB - We demonstrate the establishment of a novel animal model for trigeminal neuropathic pain following compression of the trigeminal nerve root, which produces prolonged nociceptive behavior and demyelination of the trigeminal nerve root. Under anesthesia, male Sprague-Dawley rats (200-230. g) were mounted onto a stereotaxic frame and injections of a 4% agar solution (10 μl) were given to achieve compression of the trigeminal nerve root. A sham operation was performed using identical procedures but without agar injections. Nociceptive behavior was examined 3. days before and then at 3, 7, 10, 14, 17, 21, 24, 30, 40, 55, and 70. days after the surgery. Compression of the trigeminal nerve root caused mechanical allodynia, hyperalgesia, and cold hypersensitivity. Mechanical allodynia was established within 3. days and recovered to preoperative levels on postoperative day (POD) 40. Mechanical hyperalgesia and cold hypersensitivity persisted until 55. days following compression. The compression produced focal demyelination in the trigeminal nerve root. In the medullary dorsal horn, phospho-p38 (p-p38) mitogen-activated protein kinase (MAPK) was found to be exclusively expressed in the microglia on POD 14. Furthermore, intraperitoneal administration of carbamazepine (50. mg/kg) significantly blocked mechanical allodynia and reduced p38 MAPK activation induced by the compression of the trigeminal nerve root. Our findings suggest that prolonged nociceptive behavior following compression of the trigeminal nerve root may mimic trigeminal neuralgia in this animal model and that the activation of p38 MAPK in the microglia contributes to pain hypersensitivity in rats that have undergone compression of the trigeminal nerve root.
KW - Animal model
KW - Carbamazepine
KW - Hyperalgesia
KW - Neuropathic pain
KW - Trigeminal neuralgia
UR - http://www.scopus.com/inward/record.url?scp=84862848381&partnerID=8YFLogxK
U2 - 10.1016/j.pnpbp.2012.03.002
DO - 10.1016/j.pnpbp.2012.03.002
M3 - Article
C2 - 22449477
AN - SCOPUS:84862848381
SN - 0278-5846
VL - 38
SP - 149
EP - 158
JO - Progress in Neuro-Psychopharmacology and Biological Psychiatry
JF - Progress in Neuro-Psychopharmacology and Biological Psychiatry
IS - 2
ER -