Differences between Orofacial Inflammation and Cancer Pain

• Published in: Journal of dental research Vol. 89; no. 6; pp. 615 - 620
• Main Authors: Harano, N., Ono, K., Hidaka, K., Kai, A., Nakanishi, O., Inenaga, K.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.06.2010; International Association for Dental Research; SAGE PUBLICATIONS, INC
• Subjects: Animals; Anti-Inflammatory Agents, Non-Steroidal - administration & dosage; Anti-Inflammatory Agents, Non-Steroidal - therapeutic use; Biological and medical sciences; Calcitonin Gene-Related Peptide - analysis; Calcitonin Gene-Related Peptide - drug effects; Carcinoma 256, Walker - physiopathology; Dentistry; Disease Models, Animal; Facial Neoplasms - drug therapy; Facial Neoplasms - physiopathology; Facial Pain - drug therapy; Facial Pain - physiopathology; Galanin - analysis; Galanin - drug effects; Hot Temperature; Hyperalgesia - drug therapy; Hyperalgesia - physiopathology; Indomethacin - administration & dosage; Indomethacin - therapeutic use; Inflammation - physiopathology; Injections, Intraperitoneal; Male; Medical sciences; Neuropeptides - analysis; Neuropeptides - drug effects; Neurotransmitter Agents - analysis; Otorhinolaryngology. Stomatology; Pain Threshold - drug effects; Pain Threshold - physiology; Physical Stimulation; Rats; Rats, Wistar; Reaction Time - drug effects; Reaction Time - physiology; Substance P - analysis; Substance P - drug effects; Touch; Trigeminal Caudal Nucleus - drug effects; Trigeminal Caudal Nucleus - physiopathology; Tumors; Upper respiratory tract, upper alimentary tract, paranasal sinuses, salivary glands: diseases, semeiology; Vibrissae; neuropathic pain; immunohistochemistry; orofacial cancer model; orofacial inflammation model; indomethacin; Immunohistochemistry; Oral cancer; Rat; Pathogenesis; Indometacin; Tocolytic; Neuropathic pain; Complication; Neurological disorder; Face; Nervous system diseases; Stomatology; Rodentia; Inflammation; Malignant tumor; Non steroidal antiinflammatory agent; Oral cavity; Anatomic pathology; Vertebrata; Mammalia; Animal; Oral cavity disease; Neuralgia; Comparative study; Cancer
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/0022034510363095

Rat models of orofacial cancer exhibit both allodynia and hyperalgesia; however, it is unclear whether cancer-induced pain is secondary to cancer-induced inflammation. To address this question, we compared the effects of an anti-inflammatory drug, indomethacin, on pain and neurochemical changes in the medullary dorsal horn in orofacial inflammation and cancer models. Daily peripheral administration of indomethacin largely suppressed mechanical allodynia and thermal hyperalgesia in the inflammation model. The same procedure suppressed allodynia and hyperalgesia in the cancer model, but the suppression was weak when compared with that in the inflammation model. In the medullary dorsal horn, calcitonin gene-related peptide and substance P levels were significantly increased in the inflammation model, but did not change in the cancer model. These results suggest that pain in the orofacial cancer model is not significantly mediated by cancer-induced peripheral inflammation, although it may have some involvement.