Department of Restorative Sciences, Division of Endodontics, University of Minnesota School of Dentistry, Minneapolis, Minnesota, USA.
J Endod. 2011 Aug;37(8):1098-101. doi: 10.1016/j.joen.2011.03.007. Epub 2011 Apr 23.
Studies to examine sex differences in response to pain have suggested that females exhibit lower threshold responses to painful stimuli and that threshold response varies greatly at different stages of the menstrual cycle. Additional studies suggest that sex differences may be caused by societal sex roles or differences in anxiety responses by men and women.
The purpose of this study was to evaluate biologically evident sex differences in male and female rats chronically treated with a systemic algogen, the nerve growth factor (NGF), by measuring neuropeptides (calcitonin gene-related peptide) content and release from isolated dental pulp.
Rats were injected subcutaneously every other day with either murine NGF (1 mg/kg) or vehicle for 7 or 13 days. Isolated incisor pulp tissue was evaluated from these male and female rats (n = 96). Capsaicin-evoked neurosecretion of CGRP and tissue content were measured using a previously validated radioimmunoassay.
Dental pulp from female rats at 7 days showed significantly increased capsaicin-evoked immunoreactive CGRP release (>50% increase) compared with tissue from male rats. After 13 days, this release was significantly increased only in NGF-treated female rats (3-fold increase) when compared with control females or both male groups. The CGRP content in tissue from both female groups was also significantly increased after 7 days of treatment (>3 fold), but after 13 days this content was only significantly increased in tissue from NGF-treated female rats (P = .0001).
These data suggest that sex differences affect the role of NGF in the modulation of inflammation through the regulation of peripheral neuropeptide release and content.
研究表明，在对疼痛的反应方面存在性别差异，女性对疼痛刺激的阈值反应较低，并且阈值反应在月经周期的不同阶段变化很大。其他研究表明，性别差异可能是由社会性别角色或男女焦虑反应的差异引起的。
本研究旨在通过测量分离的牙髓中神经肽（降钙素基因相关肽）的含量和释放，评估慢性给予全身性致痛剂神经生长因子（NGF）的雄性和雌性大鼠中生物学上明显的性别差异。
大鼠每隔一天皮下注射鼠源性 NGF（1mg/kg）或载体，共 7 或 13 天。从这些雄性和雌性大鼠（n=96）中评估离体切牙牙髓组织。使用先前验证的放射免疫测定法评估辣椒素诱导的 CGRP 神经分泌和组织含量。
与雄性大鼠的组织相比，7 天的雌性大鼠牙髓中的辣椒素诱导的免疫反应性 CGRP 释放明显增加（增加超过 50%）。13 天后，与对照雌性大鼠或两组雄性大鼠相比，仅 NGF 治疗的雌性大鼠的这种释放显著增加（增加 3 倍）。两组雌性大鼠的组织中 CGRP 含量在治疗 7 天后也显著增加（增加超过 3 倍），但 13 天后，仅 NGF 治疗的雌性大鼠的组织中 CGRP 含量显著增加（P=0.0001）。
这些数据表明，性别差异影响 NGF 在调节外周神经肽释放和含量方面对炎症的调节作用。
