长春碱(VCR)是一种著名的化疗药物，经常引起神经病理性疼痛。从马兜铃属梗菜(Ajuga Bracteosa)中分离出的Ajugarin-I (Aju-I)具有抗氧化、抗炎和神经保护特性。本研究旨在调查Aju-I对VCR诱导的神经病理性疼痛的改善潜力并探讨涉及的潜在机制。首先，通过针对过氧化氢(H2O2)诱发的PC12细胞毒性和氧化应激，确定了Aju-I的神经保护潜力。针对神经病理性疼痛诱导，将长春碱腹腔注射给同龄成年雄性白化小鼠(BALB/c)十天(1-10天)。神经病理性诱导术后在第11到21天期间经腹腔注射Aju-I(1和5mg/kg)。初始行为学测试如热性高觉、机械性异感和冷性异感，以探究Ajugarin-I(1和5mg/kg, b.w)的抗痛觉效能。通过免疫组化和western blot确定了核因子-红细胞因子2相关因子2(Nrf2)、核因子-κB(NF-κB)、BCL2相关×蛋白(Bax)和B细胞淋巴瘤-2(Bcl-2)信号蛋白。此外，还测量了脊髓和坐骨神经中的炎症因子、抗氧化剂和氧化应激参数。行为结果表明，Aju-I (5mg/kg)显著减轻了VCR诱导的神经病理性疼痛行为，包括高觉和异感。它逆转了VCR在坐骨神经、脊髓和大脑中引起的组织学改变。它通过调节Nrf2/NF-κB信号的免疫反应显著减轻了氧化应激和炎症。它通过调节Bcl-2/Bax和Caspase-3的免疫反应抑制了凋亡。流式细胞仪和彗星分析也证实了其抗凋亡潜力。它显著改善了抗氧化状态，并减轻了VCR诱导的炎症因子。高效液相色谱分析表明，Aju-I越过了血脑屏障(BBB)并渗透到了脑组织中。这些发现表明Aju-I治疗通过调节Nrf2/NF-κB和Bcl2信号抑制了长春碱引起的神经病变。版权所有©2023 Elsevier B.V.

Vincristine (VCR) is a well-known chemotherapeutic agent that frequently triggers neuropathic pain. Ajugarin-I (Aju-I) isolated from Ajuga bracteosa exerts antioxidant, anti-inflammatory, and neuroprotective properties. The present study was designed to investigate the ameliorative potential of Aju-I against VCR-induced neuropathic pain and explored the underlying mechanism involved. The neuroprotective potential of Aju-I was first confirmed against hydrogen peroxide (H2O2)-induced cytotoxicity and oxidative stress in PC12 cells. For neuropathic pain induction, vincristine was given intraperitoneally (i.p.) into adult male albino mice (BALB/c) of the same age (8-12 weeks old) for 10 days (days 1-10). Aju-I (1 and 5 mg/kg) doses were administered from day 11 to 21 intraperitoneally (i.p.) after the neuropathic induction. Initially, behavioral tests such as thermal hyperalgesia, mechanical allodynia, and cold allodynia were performed to investigate the antinociceptive potential of Ajugarin-I (1 and 5 mg/kg, b.w). The nuclear factor-erythroid factor 2-related factor 2(Nrf2), nuclear factor-κB (NF-κB), BCL2-associated × protein (Bax), and B-cell-lymphoma-2 (Bcl-2) signaling proteins were determined by immunohistochemistry and western blot. Additionally, inflammatory cytokines, antioxidant, and oxidative stress parameters were also measured in the spinal cord and sciatic nerve. The behavioral results demonstrated that Aju-I (5 mg/kg) markedly alleviated VCR-induced neuropathic pain behaviors including hyperalgesia and allodynia. It reversed the histological alterations caused by VCR in the sciatic nerve, spinal cord, and brain. It significantly alleviated oxidative stress and inflammation by regulating the immunoreactivity of Nrf2/NF-κB signaling. It suppressed apoptosis by regulating the immunoreactivity of Bcl-2/Bax and Caspase-3. The flow cytometry and comet analysis also confirmed its anti-apoptotic potential. It considerably improved the antioxidant status and mitigated VCR-induced inflammatory cytokines. High-performance liquid chromatography (HPLC) analysis indicated that Aju-I crosses the blood-brain barrier (BBB) and penetrated the brain tissue. These findings suggest that Aju-I treatment inhibited vincristine-induced neuropathy via regulation of Nrf2/NF-κB and Bcl2 signaling.Copyright © 2023 Elsevier B.V. All rights reserved.