Sapkota Arjun, Gaire Bhakta Prasad, Cho Kyu Suk, Jeon Se Jin, Kwon Oh Wook, Jang Dae Sik, Kim Sun Yeou, Ryu Jong Hoon, Choi Ji Woong
College of Pharmacy and Gachon Institute of Pharmaceutical Sciences, Gachon University, Incheon, Republic of Korea.
Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, Republic of Korea.
PLoS One. 2017 Feb 8;12(2):e0171479. doi: 10.1371/journal.pone.0171479. eCollection 2017.
Microglial activation and its-driven neuroinflammation are characteristic pathogenetic features of neurodiseases, including focal cerebral ischemia. The Artemisia asiatica (Asteraceae) extract and its active component, eupatilin, are well-known to reduce inflammatory responses. But the therapeutic potential of eupatilin against focal cerebral ischemia is not known, along with its anti-inflammatory activities on activated microglia. In this study, we investigated the neuroprotective effect of eupatilin on focal cerebral ischemia through its anti-inflammation, particularly on activated microglia, employing a transient middle cerebral artery occlusion/reperfusion (tMCAO), combined with lipopolysaccharide-stimulated BV2 microglia. Eupatilin exerted anti-inflammatory responses in activated BV2 microglia, in which it reduced secretion of well-known inflammatory markers, including nitrite, IL-6, TNF-α, and PGE2, in a concentration-dependent manner. These observed in vitro effects of eupatilin led to in vivo neuroprotection against focal cerebral ischemia. Oral administration of eupatilin (10 mg/kg) in a therapeutic paradigm significantly reduced brain infarction and improved neurological functions in tMCAO-challenged mice. The same benefit was also observed when eupatilin was given even within 5 hours after MCAO induction. In addition, the neuroprotective effects of a single administration of eupatilin (10 mg/kg) immediately after tMCAO challenge persisted up to 3 days after tMCAO. Eupatilin administration reduced the number of Iba1-immunopositive cells across ischemic brain and induced their morphological changes from amoeboid into ramified in the ischemic core, which was accompanied with reduced microglial proliferation in ischemic brain. Eupatilin suppressed NF-κB signaling activities in ischemic brain by reducing IKKα/β phosphorylation, IκBα phosphorylation, and IκBα degradation. Overall, these data indicate that eupatilin is a neuroprotective agent against focal cerebral ischemia through the reduction of microglial activation.
小胶质细胞激活及其引发的神经炎症是包括局灶性脑缺血在内的神经疾病的典型致病特征。众所周知，亚洲蒿（菊科）提取物及其活性成分灯盏乙素可减轻炎症反应。但灯盏乙素对局灶性脑缺血的治疗潜力及其对活化小胶质细胞的抗炎活性尚不清楚。在本研究中，我们通过采用短暂性大脑中动脉闭塞/再灌注（tMCAO）联合脂多糖刺激的BV2小胶质细胞，研究了灯盏乙素通过其抗炎作用，特别是对活化小胶质细胞的抗炎作用，对局灶性脑缺血的神经保护作用。灯盏乙素在活化的BV2小胶质细胞中发挥抗炎反应，以浓度依赖的方式减少包括亚硝酸盐、IL-6、TNF-α和PGE2在内的知名炎症标志物的分泌。这些在体外观察到的灯盏乙素的作用导致了对局灶性脑缺血的体内神经保护。在治疗模式下口服灯盏乙素（10 mg/kg）可显著减少tMCAO诱导的小鼠脑梗死并改善神经功能。即使在MCAO诱导后5小时内给予灯盏乙素，也观察到了同样的益处。此外，在tMCAO攻击后立即单次给予灯盏乙素（10 mg/kg）的神经保护作用在tMCAO后持续长达3天。给予灯盏乙素可减少缺血脑区Iba1免疫阳性细胞的数量，并诱导其形态从阿米巴样变为分支状，同时伴有缺血脑区小胶质细胞增殖减少。灯盏乙素通过降低IKKα/β磷酸化、IκBα磷酸化和IκBα降解来抑制缺血脑区的NF-κB信号活性。总体而言，这些数据表明灯盏乙素是一种通过减少小胶质细胞激活来对抗局灶性脑缺血的神经保护剂。
