辣椒素对大鼠面部皮肤降钙素基因相关肽和一氧化氮合酶阳性神经纤维的影响

背景辣椒素外敷治疗浅表性疼痛已为人们接受,但能否直接作用于皮下或深层组织中的神经末梢或神经治疗三叉神经痛?目的观察皮下注射辣椒素对大鼠面部皮肤降钙素基因相关肽、一氧化氮合酶阳性神经纤维的影响.设计随机对照实验.单位咸宁学院医学院解剖学教研室,华中科技大学同济医学院神经生物学研究室.材料实验于2003-10/12于华中科技大学同济医学院神经生物学研究室完成.健康Wistar大鼠20只,雌雄不拘,体质量120～170 g.方法辣椒素皮下注射处理大鼠三叉神经眶下支,大鼠左侧面区为对照侧,右侧面区为实验侧,按用量将动物分为辣椒素20μL组,辣椒素30μL组,辣椒素50μL组,辣椒素100μL组4组,每组5只.24 h取材后切片镜检,降钙素基因相关肽和一氧化氮合酶免疫组化染色.主要观察指标[1]镜检实验侧各组染色标本中降钙素基因相关肽和一氧化氮合酶阳性神经纤维的变化;图像分析降钙素基因相关肽和一氧化氮合酶的平均吸光度.[2]大鼠的特征性行为和体征改变.结果20只大鼠均进入结果分析.[1]行为变化皮下注射辣椒素溶液数分钟后,大鼠出现一系列特征性的行为和体征改变,但随着用药次数的增加,则逐渐减轻或消失.[2]镜检结果实验侧各组标本中降钙素基因相关肽和一氧化氮合酶阳性神经纤维有明显差别.[3]图像分析各组大鼠面部皮肤降钙素基因相关肽平均吸光度对照侧为0.984±0.056,辣椒素20μL组为0.947±0.025,辣椒素30 μL组为0.852±0.042,辣椒素50 μL组为0.756±0.028,辣椒素100 μL组为0.730±0.016;各组大鼠面部皮肤一氧化氮合酶平均吸光度对照侧为0.151±0.009,辣椒素20μL组为0.148±0.007,辣椒素30μL组为0.132±0.012,辣椒素50μL组为0.111±0.067,辣椒素100μL组为0.107±0.006.方差分析组间差异有显著性意义(P＜0.01).结论降钙素基因相关肽、一氧化氮合酶参与了伤害性信息处理和调控痛与镇痛的过程,辣椒素通过耗竭大量的神经递质而发挥镇痛作用.

Effect of capsaicin on calcitonin gene-related peptide and nitric oxide synthase-positive nerve fiber in rat facial skin

BACKGROUND: The effect of external application of capsaicin in the treatment of superficial pain has been recognized, but its effect against trigeminal neuralgia by direct action on the nerve ending or nerves in the hypodermis or deep tissues awaits intensive investigation.OBJECTIVE: To observes the effect of subcutaneous injection of capsaicin on calcitonin gene-related peptide (CGRP) and nitric oxide synthase(NOS)-positive nerve fibers in rat facial skin.SETTING: Teaching and Research Division of Anatomy, Xianning Medical College, and Department of Neurobiology, Tongji Medical College of Huazhong University of Science and Technology.MATERIALS: This experiment was conducted in the Laboratory of Neurobiology, Tongji Medical College, between October and December 2003.Twenty healthy Wistar rats of either sex with body mass of 120-170 g were used.METHODS: The rats received subcutaneous injection of capsaicin for treatment of the suborbital branch of the trigeminal nerve on the right side,with the left side serving as the control side. According to the doses of capsaicin applied, the rats were divided into 4 groups, namely 20, 30, 50and 100 μL capsaicin groups with 5 rats in each group. Twenty-four hours after the injections, samples were obtained and cut into slices for microscopic observation and the expressions of CGRP and NOS were examined immunohistochemically.MAIN OUTCOME MEASURES: [1] Changes of CGRP and NOS-positive nerve fibers on the experimental side and image analysis of the mean absorbance of CGRP and NOS; [2] changes of characteristic behaviors and body signs of the rats.RESULTS: Totally 20 rats entered the result analysis. [1] Behavioral change: A few minutes after subcutaneous injection of capsaicin, the rats exhibited a series of characteristic behavioral and symptomatic changes,which gradually diminished or even vanished with the increase of the doses. [2] Microscopic changes: On the experimental side, no obvious difference was noted in the expression of CGRP and NOS-positive nerve fibers between the groups. [3] Imaging analysis of the mean absorbance of CGRP and NOS: For CGRP, the mean absorbance was 0.984±0.056 on the control side and 0.947±0.025, 0.852±0.042, 0.756±0.028 and 0.730±0.016 in 20,30, 50 μL and 100 μL capsaicin groups, respectively. As for NOS, the mean absorbance was 0.151±0.009 on the control side, and was 0.148±0.007,0.132±0.012, 0.111±0.067 and 0.107±0.006 in 20, 30, 50 μL and 100 μL capsaicin groups. Analysis of variance revealed significant differences between the groups (P ＜ 0.01).CONCLUSION: CGRP and NOS participate in the processing of nociceptive information and modulate pain and analgesia. Capsaicin executes analgesic effect by exhausting massive neurotransmitters.