Soleimani Mohsen, Sheikholeslami Mohammad Abbas, Ghafghazi Shiva, Pouriran Ramin, Parvardeh Siavash
Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Iran J Basic Med Sci. 2019 Dec;22(12):1445-1451. doi: 10.22038/IJBMS.2019.14028.
Neuropathic pain is a prevalent and debilitating neurological disorder. Ample evidence indicates that microglial cells and inflammatory cytokines are involved in the pathogenesis of neuropathic pain. Alpha-terpineol is a monoterpenoid alcohol with inhibitory effect on inflammatory cytokines. The main purpose of this study was to evaluate the effect of α-terpineol on neuropathic pain in rats.
Chronic constriction injury (CCI) model was utilized to induce neuropathic pain in male rats. The rats were randomly divided into control, sham, α-terpineol, and gabapentin groups. Normal saline, α-terpineol (25, 50, and 100 mg/kg), and gabapentin (100 mg/kg) were administered intraperitoneally in the above-mentioned groups once daily for 14 days post-CCI. Behavioral tests, including Von Frey, acetone, and Hargreaves were used to assess mechanical allodynia, cold allodynia, and hyperalgesia in rats. Iba1 immunostaining and ELISA procedures were used to assess the activation of microglial cells and inflammatory cytokines level.
The results showed that α-terpineol (50 and 100 mg/kg) significantly attenuated mechanical allodynia, cold allodynia, and hyperalgesia in the neuropathic rats. The analgesic effect of α-terpineol (100 mg/kg) was comparable with that of gabapentin as a standard antineuropathic pain drug. In addition, α-terpineol (25, 50 and 100 mg/kg) significantly decreased the number of Iba1-positive cells and diminished the concentration of IL-1β and TNF-α in the spinal tissue.
It was ultimately attained that α-terpineol attenuates neuropathic pain through the suppression of the microglial cells and reduction of inflammatory cytokine levels in the spinal cord of rats.
神经性疼痛是一种常见且使人衰弱的神经系统疾病。大量证据表明，小胶质细胞和炎性细胞因子参与了神经性疼痛的发病机制。α-松油醇是一种对炎性细胞因子具有抑制作用的单萜醇。本研究的主要目的是评估α-松油醇对大鼠神经性疼痛的影响。
采用慢性缩窄损伤（CCI）模型诱导雄性大鼠产生神经性疼痛。将大鼠随机分为对照组、假手术组、α-松油醇组和加巴喷丁组。在CCI术后14天，上述各组分别腹腔注射生理盐水、α-松油醇（25、50和100mg/kg）以及加巴喷丁（100mg/kg），每日一次。采用行为学测试，包括von Frey、丙酮和哈格里夫斯测试，来评估大鼠的机械性异常性疼痛、冷异常性疼痛和痛觉过敏。采用Iba1免疫染色和酶联免疫吸附测定（ELISA）方法来评估小胶质细胞的活化情况和炎性细胞因子水平。
结果显示，α-松油醇（50和100mg/kg）显著减轻了神经性大鼠的机械性异常性疼痛、冷异常性疼痛和痛觉过敏。α-松油醇（100mg/kg）的镇痛效果与作为标准抗神经性疼痛药物的加巴喷丁相当。此外，α-松油醇（25、50和100mg/kg）显著减少了Iba1阳性细胞的数量，并降低了脊髓组织中白细胞介素-1β（IL-1β）和肿瘤坏死因子-α（TNF-α）的浓度。
最终得出，α-松油醇通过抑制大鼠脊髓中的小胶质细胞和降低炎性细胞因子水平来减轻神经性疼痛。
