Departamento de Medicina, Universidad Europea de Madrid, Spain.
Departamento de Fisiología, Facultad de Medicina, Universidad Complutense de Madrid, Spain.
Biomed Pharmacother. 2022 Jun;150:112961. doi: 10.1016/j.biopha.2022.112961. Epub 2022 Apr 19.
Shikonin is an ointment produced from Lithospermun erythrorhizon which has been used in traditional medicine both in Europe and Asia for wound healing and is associated with anti-inflammatory properties. The goal of this work is to assess the analgesic properties of Shikonin in the CFA-induced inflammation model of pain. Rats were subjected to inflammation of the hind paw by CFA injection with a preventive injection of Shikonin and compared to either a control group or to a CFA-inflamed group with the vehicle drug solution. Inflammation of the hind paw by CFA was assessed by measurement of the dorsal to plantar diameter. Mechanical thresholds were established by means of the Von Frey filaments which are calibrated filaments that exert a defined force. Finally, the spinal cord of the studied animals was extracted to analyse the microglia population through immunohistochemistry using the specific marker Iba-1. Our results show that Shikonin reduces the paw oedema caused by CFA inflammation. Subsequently, there is a concomitant restoration of the mechanical thresholds reduced by CFA hind paw injection. Additionally, spinal microglia is activated after CFA-induced inflammation. Our results show that microglia is inhibited by Shikonin and has concomitant restoration of the mechanical thresholds. Our findings demonstrate for the first time that Shikonin inhibits microglia morphological changes and thereby ameliorates pain-like behaviour elicited by mechanical stimulation.
紫草素是一种从紫草中提取的软膏，在欧洲和亚洲的传统医学中都被用于伤口愈合，并具有抗炎特性。本研究的目的是评估紫草素在 CFA 诱导的炎症疼痛模型中的镇痛作用。通过 CFA 注射使大鼠后爪产生炎症，并进行预防性紫草素注射，然后与对照组或仅用载体药物溶液处理的 CFA 炎症组进行比较。通过测量背跖直径来评估后爪的炎症。通过 Von Frey 纤维来确定机械阈值，Von Frey 纤维是一种校准纤维，可施加特定的力。最后，提取研究动物的脊髓，通过使用特异性标志物 Iba-1 进行免疫组织化学分析，来研究小胶质细胞群体。我们的结果表明，紫草素可减轻 CFA 炎症引起的爪肿胀。随后，CFA 后爪注射引起的机械阈值降低得到了相应的恢复。此外，CFA 诱导的炎症会激活脊髓小胶质细胞。我们的结果表明，紫草素抑制小胶质细胞形态变化，并同时恢复机械阈值。我们的研究结果首次表明，紫草素抑制小胶质细胞形态变化，从而改善机械刺激引起的疼痛样行为。
