小鼠创伤性脑损伤后PARP抑制剂PJ34对血脑屏障通透性及MMP-9表达的影响

Effect of PARP inhibitor PJ34 on blood-brain barrier permeability and MMP-9 expression following traumatic brain injury in mice

目的 探讨多聚腺苷二磷酸-核糖聚合酶[poly（ADP-ribose）polymerase,PARP]抑制剂PJ34对小鼠创伤性脑损伤（traumatic brain injury,TBI）后血脑屏障（blood-brain barrier,BBB）通透性及脑组织中基质金属蛋白酶-9（matrix metalloproteinases-9,MMP-9）表达变化的影响.方法 健康成年BALB/c雄性小鼠136只,按随机数字表法分为假手术组、损伤组和PARP抑制剂（PJ34）组,建立小鼠可控性皮质打击伤模型.在伤后6,24 h时,从运动、感觉、反射和平衡等方面评价小鼠的神经功能缺损;伊文思蓝法测定BBB通透性变化和干湿重法测定脑组织含水量;采用HE染色测定损伤体积,评价损伤脑区神经元的死亡;免疫印迹方法测定MMP-9的表达量.结果 （1）与损伤组[12.50±0.39、11.80±0.32、（25.37±1.75） mm^3、（28.24±1.51）mm^3]比较,P J34组[8.00±0.26、7.50±0.25、（11.25±0.91）mm^3、（13.55±1.06） mm^3]神经功能评分、脑挫裂伤体积在伤后6h和24 h均明显降低（P＜0.01）;（2）与损伤组[（936.96±4.71） μg/mg、（1 302.23-±5.89） μg/mg]比较,PJ34组[（440.08±3.10） μg/mg、（860.46±3.86） μg/mg] BBB通透性在伤后6h和24h明显降低（P＜0.01）,脑含水量PJ34组在伤后6h较损伤组显著降低[（82.55±0.73）％∶（80.77±0.76）％]（P＜0.01）,但在伤后24h无明显差异;（3）在伤后6h和24h,MMP-9的表达H34组均低于损伤组（P＜0.05或0.01） .结论 PARP抑制剂PJ34可下调小鼠TBI后MMP-9的高表达,减轻BBB通透性破坏,从而起到脑保护作用.

Objective To investigate the role of poly（ADP-ribose） polymerase （PARP） inhibitor PJ34 in regulating blood-brain barrier （BBB） permeability and matrix metalloproteinases-9 （MMP-9） expression in a mouse model of traumatic brain injury （TBI）.Methods A total of 136 adult male BALB/c mice were randomly divided into sham-operated group,injured group and PJ34-treated group according to the random number table.Controlled cortical impact in mice was established.At 6 and 24hours postinjury,neurological deficit was evaluated,including motor,sensory,reflex and beam balance tests ; BBB permeability and brain water content were detected using Evans blue test and gravimetric technique; brain contusion volume was measured using HE staining; levels of MMP-9 in cytosolic fractions were detected using Western blotting.Results At 6 and 24 hours postinjury,neurological severity score in PJ34-treated group （8.00 ± 0.26,7.50 ±0.25） were lower than those in injured group （12.50 ±0.39,11.80 ± 0.32） ; brain contusion volume in PJ34-treated group [（11.25 ± 0.91） mm3,（13.55 ±1.06） mm3] was lower than those in injured group [（25.37 ± 1.75） mm3,（28.24 ± 1.51） mm3] ; BBB permeability in PJ34-treated group [（440.08 ± 3.10） μg/mg,（860.46 ± 3.86） μg/mg] was lower than those in injured group [（936.96 ± 4.71） μg/mg,（1 302.23 ± 5.89） μg/mg] （all P 〈 0.01）.Brain water content lowered significantly in PJ34-treated group than in injured group at 6 hours postinjury [（80.77 ± 0.76） % vs （82.55 ± 0.73） %,P 〈 0.0l],but between-group difference was not significant at 24 hours postinjury.Lower levels in MMP-9 were also observed in PJ34-treated group compared with injured group at 6 and 24 hours postinjury（P 〈 0.05 or 0.01）.Conclusion PARP inhibitor PJ34 can attenuate MMP-9 up-regulation,inhibit BBB injury and hence protect the brain against TBI in mice.