薄荷酮通过减轻神经炎症来保护缺血性脑卒中模型小鼠的神经功能

Menthone protects neurological function in ischemic stroke mice by alleviating neuroinflammation

目的探究薄荷酮对缺血性脑卒中模型小鼠神经炎症的影响及其潜在机制。方法取雄性C57BL/6小鼠100只,根据体重随机划分为5组,每组各20只;假手术(Sham)组和模型(Middle cerebral artery occlusion,MCAO)组给予生理盐水治疗,低、中、高剂量薄荷酮组分别给予100、200、500 mg/kg薄荷酮治疗;除假手术组外,各组小鼠通过实施左侧大脑中动脉阻塞手术构建缺血性脑卒中模型;缺血性脑卒中后3 d进行神经功能缺损评分,并利用2,3,5-三苯基氯化四氮唑(Triphenyltetrazolium chloride,TTC)染色评估小鼠脑梗死体积;通过酶联免疫吸附试验(Enzyme linked immunosorbent assay,ELISA)测定梗死侧脑组织白介素-1β(Interleukin-1β,IL-1β)、白介素-6(Interleukin-6,IL-6)、肿瘤坏死因子-α(Tumor necrosis factor-α,TNF-α)水平;利用蛋白质免疫印迹实验分析Toll样受体4(Toll-like receptor 4,TLR4)/核转录因子-κB(Nuclear transciption factor-kappa B,NF-κB)通路蛋白的表达水平。结果与Sham组比较,MCAO组小鼠脑梗死明显,神经功能缺损评分升高,IL-1β,IL-6,TNF-α水平增高,TLR4/NF-κB通路相关蛋白表达水平上调(P<0.05);与MCAO组比较,低、中、高剂量的薄荷酮均能减小小鼠的脑梗死体积,降低神经功能缺损评分,降低IL-1β,IL-6,TNF-α水平以及下调TLR4/NF-κB通路相关蛋白表达水平(P<0.05),并且薄荷酮剂量越高,作用效果越明显(P<0.05)。结论薄荷酮可能通过抑制TLR4/NF-κB信号通路来减轻缺血性脑卒中后的神经炎症,以改善小鼠的神经功能。

Objective To investigate the effect and potential mechanism of menthone on neuroinflammation in mice with ischemic stroke.Methods 100 male C57BL/6 mice were randomly divided into 5 groups,with 20 mice in each group.The sham group and the experimental(middle cerebral artery occlusion,MCAO)group were treated with normal saline,and the low,medium,and high dose menthone groups were treated with menthone at 100,200,and 500 mg/kg,respectively.Except for the sham group,the ischemic stroke model was established by occlusion of the left middle cerebral artery in each group.3 days after MCAO,cerebral infarct volume was analyzed by 2,3,5-triphenyltetrazolium chloride(TTC)staining,and neurological deficit scores were measured.The levels of Interleukin-1β(IL-1β),Interleukin-6(IL-6),and Tumor necrosis factor-α(TNF-α)were detected by enzyme-linked immunosorbent assay.Furthermore,we performed western blot analysis to detect the expression of toll-like receptor 4(TLR4)/nuclear transcription factor kappa B(NF-κB)pathway-related proteins.Results Compared with the Sham group,the MCAO group showed significantly higher brain infarcts,higher neurological deficit scores,higher levels of IL-1β,IL-6,and TNF-α,and up-regulated expression levels of TLR4/NF-κB pathway-related proteins(P<0.05);compared with the MCAO group,the low,medium,and high doses of menthone reduced the size of brain infarcts and lowered neurological deficit scores in mice(P<0.05).In comparison with the MCAO group,the low,medium,and high doses of menthone reduced the volume of cerebral infarction,lowered the neurological deficit score,decreased IL-1,IL-6,and TNF-αlevels,and down-regulated the expression of TLR4/NF-κB pathway-related proteins(P<0.05),while the higher the dose of menthone,the more obvious the effect was(P<0.05).Conclusion Menthone could alleviate neuroinflammation after ischemic stroke by inhibiting TLR4/NF-κB signaling pathway to play a neuroprotective role.