Shimazu Yoshihito, Kobayashi Ayumu, Endo Shiori, Takemura Jin, Takeda Mamoru
Department of Life and Food Sciences, Laboratory of Food and Physiological Sciences, School of Life and Environmental Sciences, Azabu University, Sagamihara, Kanagawa, Japan.
Eur J Oral Sci. 2019 Oct;127(5):379-385. doi: 10.1111/eos.12650. Epub 2019 Sep 22.
Although lutein is known to inhibit chronic inflammation, its effect on acute inflammation-induced nociceptive processing in the trigeminal system remains to be determined. The aim of the present study was to investigate whether pretreatment with lutein attenuates acute inflammation-induced sensitization of nociceptive processing in rat spinal trigeminal nucleus caudalis (SpVc) and upper cervical (C1) dorsal horn neurons, via c-Fos immunoreactivity. Mustard oil, a transient receptor potential ankyrin-1 channel agonist, was injected into the whisker pads to induce inflammation. Pretreatment of rats with lutein resulted in significant decreases in the inflammation-induced mean times of face grooming and the thickness of inflammation-induced edema in whisker pads relative to those features in inflamed rats (i.e., rats with no lutein pretreatment). In both the ipsilateral superficial and deep laminae of the SpVc and C1 dorsal horn, there were significantly larger numbers of c-Fos-positive neurons in inflamed rats than in naïve rats, and lutein pretreatment significantly decreased that number relative to inflamed rats. These results suggest that systemic administration of lutein attenuates acute inflammation-induced nocifensive behavior and augmented nociceptive processing of SpVc and C1 neurons that send stimulus localization and intensity information to higher pain centers. These findings support lutein as a potential therapeutic agent for use as an alternative, complementary medicine to attenuate, or even prevent, acute inflammatory pain.
尽管已知叶黄素可抑制慢性炎症，但其对三叉神经系统中急性炎症诱导的伤害性处理的影响仍有待确定。本研究的目的是通过c-Fos免疫反应性，研究叶黄素预处理是否能减轻大鼠延髓三叉神经尾侧核（SpVc）和颈上（C1）背角神经元中急性炎症诱导的伤害性处理致敏。将芥末油（一种瞬时受体电位锚蛋白-1通道激动剂）注射到触须垫中以诱导炎症。与未进行叶黄素预处理的炎症大鼠（即发炎大鼠）相比，用叶黄素预处理大鼠可使炎症诱导的面部梳理平均时间和触须垫中炎症诱导的水肿厚度显著降低。在SpVc和C1背角的同侧浅层和深层中，发炎大鼠的c-Fos阳性神经元数量明显多于未发炎大鼠，且叶黄素预处理相对于发炎大鼠显著减少了该数量。这些结果表明，全身给予叶黄素可减轻急性炎症诱导的伤害性防御行为，并增强向更高疼痛中枢传递刺激定位和强度信息的SpVc和C1神经元的伤害性处理。这些发现支持叶黄素作为一种潜在的治疗剂，用作替代、补充药物来减轻甚至预防急性炎性疼痛。
