Université de Montréal, Faculté de Médecine Vétérinaire, Département de Biomédecine Vétérinaire, Saint-Hyacinthe, QC, Canada.
Phytother Res. 2010 Nov;24(11):1645-53. doi: 10.1002/ptr.3174.
The main objective of this study was to determine the central effect of eugenol on neuropathic pain when injected intrathecally at the level of the lumbar spinal cord. In a preliminary study the penetrability of eugenol was evaluated in the CNS of rats. Blood, brain and spinal cord samples were collected at selected time points following eugenol administration and concentrations were determined by tandem liquid chromatography-mass spectrometry. Brain-to-plasma and spinal cord-to-plasma ratios (3.3 and 6.7, respectively) suggest that eugenol penetrates relatively well the CNS of rats, with a preferential distribution in the spinal cord. Following the induction of neuropathic pain in rats using the sciatic nerve ligation model, intrathecal injections of eugenol were done to evaluate the central effect of eugenol. Treatment with 50 μg of eugenol significantly decreased secondary mechanical allodynia after 15 min, 2 h and 4 h (p < 0.05; <0.005; <0.05, respectively) and improved thermal hyperalgesia after 2 h and 4 h (p < 0.001 and p < 0.05). The results support the hypothesis that eugenol may alleviate neuropathic pain, both allodynia and hyperalgesia, by acting centrally most probably at the level of the dorsal horn of the spinal cord where vanilloid receptors can be found.
本研究的主要目的是确定 Eugenol 在鞘内注射到腰椎脊髓水平时对神经性疼痛的中枢作用。在初步研究中，评估了 Eugenol 在大鼠中枢神经系统中的穿透性。在 Eugenol 给药后选择时间点采集血液、脑和脊髓样本，并通过串联液质联用测定浓度。脑-血浆和脊髓-血浆比值（分别为 3.3 和 6.7）表明 Eugenol 相对较好地穿透大鼠中枢神经系统，在脊髓中具有优先分布。使用坐骨神经结扎模型在大鼠中诱导神经性疼痛后，进行鞘内注射 Eugenol 以评估 Eugenol 的中枢作用。50 μg Eugenol 的治疗可显著降低 15 分钟、2 小时和 4 小时后的继发性机械性痛觉过敏（p < 0.05；<0.005；<0.05），并改善 2 小时和 4 小时后的热痛觉过敏（p < 0.001 和 p < 0.05）。结果支持 Eugenol 可能通过作用于脊髓背角来缓解神经性疼痛（包括痛觉过敏和痛觉过度）的假设，而脊髓背角可以发现香草素受体。
