Flake Natasha M, Hermanstyne Tracey O, Gold Michael S
University of Maryland Dental School, Department of Biomedical Sciences, Rm. 5-A-12 HHH, 666 West Baltimore St., Baltimore, MD 21201, USA.
Am J Physiol Regul Integr Comp Physiol. 2006 Aug;291(2):R343-8. doi: 10.1152/ajpregu.00835.2005. Epub 2006 Feb 9.
The present study was designed to test the hypothesis that estrogen exacerbates inflammation of the temporomandibular joint (TMJ). Evans blue dye was used to quantify plasma extravasation (PE) around the rat TMJ. In an initial set of experiments, TMJ PE was compared in naïve intact male and female rats, as well as in both groups after complete Freund's adjuvant (CFA)-induced inflammation of the TMJ. In contrast to our hypothesis, TMJ PE was significantly greater in both naïve and CFA-inflamed male rats than in females. To determine whether these differences were due to gonadal hormones, four additional groups of rats were studied: gonadectomized (Gx) males and females, Gx males with chronic testosterone (T) replacement, and Gx females with chronic estrogen (E) replacement. The sex difference in baseline TMJ PE appeared to reflect the actions of T. However, in the presence of TMJ inflammation, T augmented TMJ PE in males, while E attenuated TMJ PE in females. Changes in PE were also assessed in the contralateral TMJ. Results from this analysis indicated that there is a transient contralateral increase in TMJ PE in females but not males. Given that there is an inverse relationship between PE and joint damage, our results suggest that testosterone may mitigate, but estrogen may exacerbate, TMJ damage, particularly in the presence of overt inflammation. Importantly, our results may help explain both the higher prevalence and severity of temporomandibular disorder pain in females than males.
本研究旨在验证雌激素会加剧颞下颌关节（TMJ）炎症这一假说。采用伊文思蓝染料对大鼠颞下颌关节周围的血浆外渗（PE）进行定量分析。在最初的一组实验中，比较了未处理的完整雄性和雌性大鼠的颞下颌关节血浆外渗情况，以及在两组大鼠经完全弗氏佐剂（CFA）诱导颞下颌关节炎症后的血浆外渗情况。与我们的假说相反，未处理的和CFA诱导炎症的雄性大鼠的颞下颌关节血浆外渗均显著高于雌性大鼠。为了确定这些差异是否归因于性腺激素，又对另外四组大鼠进行了研究：去势（Gx）雄性和雌性大鼠、接受慢性睾酮（T）替代治疗的去势雄性大鼠以及接受慢性雌激素（E）替代治疗的去势雌性大鼠。基线颞下颌关节血浆外渗的性别差异似乎反映了睾酮的作用。然而，在存在颞下颌关节炎症的情况下，睾酮会增加雄性大鼠的颞下颌关节血浆外渗，而雌激素会减轻雌性大鼠的颞下颌关节血浆外渗。还对另一侧颞下颌关节的血浆外渗变化进行了评估。该分析结果表明，雌性大鼠的另一侧颞下颌关节血浆外渗会出现短暂增加，而雄性大鼠则不会。鉴于血浆外渗与关节损伤呈负相关，我们的研究结果表明，睾酮可能减轻，但雌激素可能加剧颞下颌关节损伤，尤其是在存在明显炎症的情况下。重要的是，我们的研究结果可能有助于解释为什么女性颞下颌关节紊乱疼痛的患病率和严重程度高于男性。
