신경섬유 말단에서의 유해자극 인지과정에는 신경성장인자 (nerve growth factor [NGF])와 감각성 신경펩티드가 관여하고, 또한 이들은 중추신경계에도 광범위하게 분포되어 있다. 본 연구는 인체 혈액과 타액에서 NGF와 감각성 신경펩티드(substance P [SP], calcitonin gene-related peptide [CGRP])의 농도를 조사하여 다양한 구강안면통증 증상들과의 관계를 알아보고자 시행되었다. 67명의 구강안면통증 환자 (관절 통증, 치아 혹은 치주 통증, 점막 통증)와 36명의 건강한 성인에서 혈장과 안정시 전타액을 채취하여 효소면역분석법 (enzyme immunoassay)을 이용하여 NGF, SP, CGRP의 농도를 측정하였다. 만성통증척도 (Graded Chronic Pain Scale) 설문지를 이용하여 각 피실험자들의 통증강도를 조사하였으며 안정시 전타액의 타액분비율 또한 측정하였다. 관절 통증 환자군은 치아 통증 환자군, 점막 통증 환자군, 대조군 각각에 비하여 유의하게 높은 혈장 내 NGF 농도를 나타내었다. 치아 통증 환자군의 혈장 내 NGF 농도는 대조군에 비하여 유의하게 높았다. 치아 통증 환자군의 타액 내 SP 농도와 점막 통증 환자군의 타액 내 CGRP 농도 또한 대조군에 비하여 유의하게 높았다. 관절 통증 환자군의 혈장 및 타액 내 SP 농도는 통증 강도와 유의한 상관관계를 보였다. 치아 통증 환자군과 점막 통증 환자군에서, 혈장 내 SP 농도, 타액 내 SP 농도, 타액 내 CGRP 농도는 연령에 따라 증가하였다. 혈장과 타액에서의 신경성장인자와 신경펩티드 검사는 다양한 구강안면통증의 특성과 예후를 평가하는데 도움을 줄 수 있으리라 생각된다.
Nerve growth factor (NGF) and sensory neuropeptides are involved in the process of nociception at peripheral nerve fibers and wide spread in central nervous system. The aims of this study were to investigate NGF and sensory neuropeptides (substance P [SP] and calcitonin gene-related peptide [CGRP]) levels in human plasma and saliva, and the associations between these sensory neuropeptides levels and chronic orofacial pain symptoms. NGF, SP, and CGRP levels in plasma and resting whole saliva samples collected from 67 orofacial pain patients (joint pain, dental or periodontal pain, mucosal pain) and 36 pain free control subjects were measured by enzyme immunoassay. The characteristic pain intensity of each subject was measured using the Graded Chronic Pain Scale and the flow rate of resting whole saliva was measured. Joint pain patients group showed significantly higher plasma NGF level compared to each of dental pain patients (p<0.01), mucosal pain patients (p<0.01), and control group (p<0.01). Plasma NGF level of dental pain patients group was significantly higher than that of control group (p<0.01). Saliva SP level of dental pain patients group (p<0.05) and saliva CGRP level of mucosal pain group (p<0.05) were significantly higher than that of control group. Plasma and saliva SP levels of joint pain patients was significantly associated with pain intensity (plasma: standardized coefficient=0.599, p<0.01, saliva: standardized coefficient=0.504, p=0.05). In dental pain patients group, plasma SP (standardized coefficient=0.559, p<0.01), saliva SP (standardized coefficient=0.520, p<0.01) and saliva CGRP (standardized coefficient=0.599, p<0.01) levels were significantly associated with age. In mucosal pain patients group, plasma SP (standardized coefficient=0.495, p<0.05), saliva SP (standardized coefficient=0.500, p<0.05), and saliva CGRP (standardized coefficient=0.717, p<0.01) levels were significantly associated with age. NGF and neuropeptides may play a role in the maintenance of various orofacial pain symptoms. The examination of those levels in plasma and saliva helps understanding the mechanism of orofacial pain, and furthermore, can be applied to the diagnosis and therapy of orofacial pain.
