脂氧素A4对大鼠局灶性脑缺血再灌注损伤时炎性反应的影响

Effects of lipoxin A4 on inflammatory response to focal cerebral ischemia-reperfusion injury in rats

目的 探讨脂氧素A4对大鼠局灶性脑缺血再灌注损伤时炎性反应的影响.方法 雄性健康SD大鼠56只,体重200～250 g,随机分为3组：假手术组（S组,n=8）,缺血再灌注组（I/R组,n=24）,脂氧素A4组（LXA4组,n=24）.采用线栓法阻塞大鼠右侧大脑中动脉制备局灶性脑缺血再灌注模型,LXA4组脑缺血后5 min经侧脑室注射脂氧素A4 0.03 nmol/5 μl,S组和I/R组注射等容量生理盐水,缺血2 h后拔出线栓行再灌注.再灌注24 h时行神经功能缺陷评分,然后断头取脑,光镜下观察病理学,采用比色法检测髓过氧化物酶活性,免疫组织化学方法检测星形胶质细胞和小胶质细胞的活化,ELISA法检测再灌注1、6、12、24和48 h时TNF-α、IL-β、转化生长因子β（TGF-β1）及IL-10的含量.结果 与S组比较,I/R组大鼠神经功能缺陷评分、髓过氧化物酶活性、TNF-α、IL-1β、TGF-β1和IL-10的含量升高,星形胶质细胞和小胶质细胞的活化数目增多（P〈0.05）;与I/R组比较,LXA4组神经功能缺陷评分、髓过氧化物酶活性、TNF-α和IL-1β含量降低,TGF-β1,和IL-10含量升高,星形胶质细胞和小胶质细胞的活化数目减少（P〈0.05）.病理结果显示：LXA4组脑缺血再灌注损伤程度较I/R组减轻.结论 脂氧素A4可通过抑制炎性反应减轻大鼠局灶性脑缺血再灌注损伤.

Objective To investigate the effects of lipoxin A4 （LXA4） on the inflammatory response to focal cerebral ischemia-reperfusion（I/R） inmy in rats.Methods Fifty-six healthy male SD rats weighing 200-250 g were randomly divided into 3 groups：group Ⅰ sham operation（group S,n=8）;group Ⅱ cerebral I/R（n=24）and group Ⅲ lipoxin A4＋I/R（group LXA4,n=24）.Right mid-cerebral artery was occluded for 2 h by inserting cranially a nylon thread with rounded tip into internal carotid artery.LXA4 0.03 nmol/5 μl was injected into cerebral ventricle at 5 min after cerebral ischemia.Neurological deficit was scored at 24 h of reperfusion.Then four animals in each group were killed and their brains were removed for microscopic examination and expression of MPO at 24 h of reperfusion.Meantime,content of IL-1β,TNF-α,TGF-β1,and IL-10 in the brain tissue were measured at 1,6,12,24 and 48 h of reperfusion by ELISA.Glial cell activity was examined at 24 h of reperfusion by immuno-histochemistry.Results Intra-cerebroventricular administrated LXA4 0.03 nmol/5 μl provided mild neuroprotection against focal cerebral I/R injury,improved neurological deficits,and reduced morphological brain damages and PMN infiltration.LXA4 also decreased the content of TNF-α and IL-1β,and increased the content of IL-10 and TGF-β1.The numbers of activated astroglia and microglia were decreased in group LXA4 compared with group I/R.Conclusion LXA4 protects the brain against I/R injury by inhibiting inflammatory response.