目的 探討牡荊素對大鼠大腦中動脈缺血再灌注損傷的保護(hù)作用及可能機(jī)制。方法 60只雄性SD大鼠隨機(jī)分為假手術(shù)組、模型組及牡荊素40、80 mg/（kg·d）組，每組15只。制作大鼠大腦中動脈缺血（90 min）/再灌注（24 h）損傷模型。術(shù)前1周及模型制作前30 min，各組分別ip相應(yīng)藥物，假手術(shù)組和模型組給予等量生理鹽水。觀察牡荊素對神經(jīng)功能缺損評分、腦指數(shù)及梗死體積的影響，采用激光多普勒血流儀監(jiān)測再灌注后大鼠缺血側(cè)局部腦血流量的動態(tài)變化，測定缺血側(cè)腦組織活性氧（ROS）水平、超氧化物歧化酶（SOD）活力、丙二醛（MDA）含量、Caspase-3活性及12羥二十烷四烯酸（12-HETE）、15羥二十烷四烯酸（15-HETE）含量；實(shí)時熒光定量PCR檢測Bcl-2、Bax、ALOX15 mRNA的表達(dá)，Western blotting檢測ALOX15蛋白、p38MAPK及p-p38MAPK蛋白表達(dá)。結(jié)果 與假手術(shù)組相比，模型組大鼠神經(jīng)缺失癥狀評分、腦指數(shù)及梗死體積顯著升高（P<0.01），ALOX15 mRNA和蛋白的表達(dá)及p38MAPK和p-p38MAPK蛋白表達(dá)顯著增加（P<0.01），同時Caspase-3活性、Bax mRNA表達(dá)明顯升高（P<0.01），而Bcl-2 mRNA表達(dá)顯著下降（P<0.01）。與模型組比較，牡荊素預(yù)處理能能顯著改善模型大鼠神經(jīng)功能缺損癥狀，降低腦指數(shù)，減少梗死體積，增加缺血側(cè)大腦局部血流量，明顯增加缺血側(cè)腦組織Bcl-2 mRNA表達(dá)（P<0.05、0.01），提高SOD活性（P<0.05、0.01），降低ALOX15 mRNA、Bax mRNA和ALOX15、p38MAPK和p-p38MAPK蛋白表達(dá)（P<0.05、0.01），下調(diào)Caspase-3活性、15-HETE、12-HETE的表達(dá)和MDA水平（P<0.05、0.01）及減少ROS的生成（P<0.05、0.01）。結(jié)論 牡荊素對局灶性缺血大腦具有神經(jīng)保護(hù)作用，并可改善缺血側(cè)大腦血流供應(yīng)。其作用機(jī)制可能為通過12/15-LOX信號抑制p38MAPK介導(dǎo)的細(xì)胞凋亡，同時降低氧化應(yīng)激和炎癥，從而減輕腦I/R損傷。

Objective To investigate the protective effect and possible mechanism of vitexin on middle cerebral artery ischemia-reperfusion injury in rats. Methods Sixty male SD rats were randomly divided into sham operation group, model group and vitexin [40, 80 mg/(kg·d) ] treatment groups. The middle cerebral artery ischemia (90 min) /reperfusion (24 h) injury model was established. One week before operation and 30 minutes before model making, rats in each group were administrated the corresponding drugs by intraperitoneally injected. Rats in the sham operation group and the model group were given the same amount of normal saline. The effect of vitexin on neurological deficit score, brain index and infarct volume were observed. The dynamic changes of cerebral blood flow in the ischemic side were monitored by laser Doppler flowmetry. The levels of ROS, SOD, MDA, Caspase-3, 12-HETE and 15-HETE were measured. The expression of Bcl-2, Bax, ALOX15 mRNA was detected by real-time fluorescence quantitative analysis. The expression of ALOX15, p38MAPK and p-p38MAPK protein were detected by Western blotting. Results Compared with the sham operation group, the neurological deficit symptom score, brain index and infarct volume of rats in the model group were significantly increased (P<0.01), the expression of ALOX15 mRNA and protein and the expression of p38MAPK and phospho-p38mapk protein were significantly increased (P<0.01), the activity of Caspase-3 and the expression of Bax mRNA were significantly increased (P<0.01), while the expression of bcl-2 mRNA was significantly decreased (P<0.01). Compared with the model group, vitexin pretreatment could significantly improve the symptoms of neurological deficit, reduce brain index and infarct volume, increase regional cerebral blood flow, increase Bcl-2 mRNA expression (P<0.05, 0.01), increase SOD activity (P<0.05, 0.01), and reduce ALOX15 mRNA and Bax MRNA and protein expressions of ALOX15, p38MAPK and phospho-p38mapk (P<0.05, 0.01), caspase-3 activity, 15-HETE, 12-HETE expression and MDA level were down regulated (P<0.05, 0.01), and ROS production was reduced (P<0.05, 0.01). Conclusion Vitexin has neuroprotective effect on focal cerebral ischemia and can improve the blood supply of ischemic side. The mechanism may be that Vitexin may inhibit p38MAPK mediated apoptosis through 12/15-LOX signal, and reduce oxidative stress and inflammation, thereby reducing brain I/R injury.

R285.5

新鄉(xiāng)醫(yī)學(xué)院海外博士科研啟動基金資助項(xiàng)目（505018）；新鄉(xiāng)醫(yī)學(xué)院科研培育基金資助項(xiàng)目（2014QN120）