Department of Orthopedic Surgery, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Shizuoka, Japan.
Department of Cellular and Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Shizuoka, Japan.
Cells. 2022 Dec 19;11(24):4130. doi: 10.3390/cells11244130.
The role of endogenous cannabinoids in neuropathic pain has been actively studied, among which 2-arachidonoyl glycerol (2-AG) has received the most attention. However, owing to its chemical properties, direct detection of 2-AG distribution in tissues is difficult. Moreover, although desorption electrospray ionization mass spectrometry imaging (DESI-MSI) has enabled the detection of 2-AG, its distribution in the brain and spinal cord of neuropathic pain models has not been reported. In this study, the expression and distribution of 2-AG in the brain and spinal cord of a spare nerve injury (SNI) mice model of neuropathic pain was examined using DESI-MSI. The brain and lumbar spinal cord were collected and analyzed on days 3, 7, and 21 after treatment. On days 3 and 7 after treatment, 2-AG expression in the SNI model was decreased in the hypothalamus, midbrain, and especially in the periaqueductal gray (PAG) region but increased in the lumbar spinal cord. On day 21, the SNI model showed decreased 2-AG expression in the hypothalamus, but the difference from the control was not significant. Furthermore, there were no differences in 2-AG expression between the lumbar spinal cord, midbrain, or PAG. These data suggest that 2-AG might be involved in pain control.
内源性大麻素在神经病理性疼痛中的作用一直受到积极研究，其中 2-花生四烯酸甘油（2-AG）受到了最多的关注。然而，由于其化学性质，直接检测组织中 2-AG 的分布较为困难。此外，尽管解吸电喷雾电离质谱成像（DESI-MSI）已经能够检测到 2-AG，但尚未报道其在神经病理性疼痛模型的大脑和脊髓中的分布。在这项研究中，使用 DESI-MSI 检查了神经病理性疼痛的 spared nerve injury（SNI）小鼠模型中大脑和脊髓中 2-AG 的表达和分布。在治疗后第 3、7 和 21 天收集并分析大脑和腰椎脊髓。在治疗后第 3 和 7 天，SNI 模型中下丘脑、中脑和特别是导水管周围灰质（PAG）区域的 2-AG 表达降低，但腰椎脊髓中的 2-AG 表达增加。在第 21 天，SNI 模型中下丘脑的 2-AG 表达降低，但与对照组相比差异不显著。此外，腰椎脊髓、中脑或 PAG 之间的 2-AG 表达没有差异。这些数据表明 2-AG 可能参与疼痛控制。
