CAJ | 학술논문

目的应用Nogo-66受体拮抗剂(sNgR1-Fc)对脑梗死大鼠进行治疗,观察其对梗死灶区域细胞轴突的保护及再生作用,并探讨其发挥作用的机制.方法取SD大鼠15只,光化学法建立大脑皮层局灶缺血梗死(PCI)模型.设假手术组、PBS组和sNgR1-Fc治疗组,PBS组于侧脑室内注射PBS,sNgR1-Fc组则注射sNgR1-Fc.在PCI术后7d,利用电镜观察各组梗死灶区域神经细胞轴突的形态学变化；Western blot技术检测梗死区细胞中RhoA,JNK及其下游的c-JUN、ATF-2蛋白的表达情况.结果光化学法可以成功复制大脑皮层局灶缺血梗死模型.电镜下,在PCI后7d,与假手术组比较,脑梗死组可见到严重的病变,无鞘纤维方面可见广泛的轴浆水肿或溶解、基质变淡；有鞘纤维方面可见广泛的髓鞘增厚或皱缩、板层紊乱,应用sNgR1-Fc处理后,上述现象均有明显改善.Western blot实验表明,在PBS组中,GTP-RhoA、p-JNK1、p-JNK2、p-c-JUN及p-ATF-2在较假手术组显著升高(P＜0.05),sNgR1-Fc处理后各因子的表达水平显著下降(P＜0.05),而Total-RhoA及Total-JNK1、Total-JNK2水平差异无统计学意义(P＞0.05).结论脑梗死发生后在较长的一段时间内都存在着显著的轴突损伤,这可能与激活RhoA/ROCK/JNK/c-Jun信号通路有关,并导致了轴突的再生受抑.而sNgR1-Fc则能有效地抑制这一通路,从而在一定程度上减轻轴突的损伤,并可能对促进轴突的再生发挥一定的作用.
목적 응용Nogo-66수체길항제(sNgR1-Fc)대뇌경사대서진행치료,관찰기대경사조구역세포축돌적보호급재생작용,병탐토기발휘작용적궤제.방법 취SD대서15지,광화학법건립대뇌피층국조결혈경사(PCI)모형.설가수술조、PBS조화sNgR1-Fc치료조,PBS조우측뇌실내주사PBS,sNgR1-Fc조칙주사sNgR1-Fc.재PCI술후7d,이용전경관찰각조경사조구역신경세포축돌적형태학변화；Western blot기술검측경사구세포중RhoA,JNK급기하유적c-JUN、ATF-2단백적표체정황.결과 광화학법가이성공복제대뇌피층국조결혈경사모형.전경하,재PCI후7d,여가수술조비교,뇌경사조가견도엄중적병변,무초섬유방면가견엄범적축장수종혹용해、기질변담；유초섬유방면가견엄범적수초증후혹추축、판층문란,응용sNgR1-Fc처리후,상술현상균유명현개선.Western blot실험표명,재PBS조중,GTP-RhoA、p-JNK1、p-JNK2、p-c-JUN급p-ATF-2재교가수술조현저승고(P＜0.05),sNgR1-Fc처리후각인자적표체수평현저하강(P＜0.05),이Total-RhoA급Total-JNK1、Total-JNK2수평차이무통계학의의(P＞0.05).결론 뇌경사발생후재교장적일단시간내도존재착현저적축돌손상,저가능여격활RhoA/ROCK/JNK/c-Jun신호통로유관,병도치료축돌적재생수억.이sNgR1-Fc칙능유효지억제저일통로,종이재일정정도상감경축돌적손상,병가능대촉진축돌적재생발휘일정적작용.
Objective To observe the protective effects of soluble Nogo-66 receptor (NgR1 )antagonist (sNgR1-Fc) on cortical axons after cortical infarction in rats,and to study the phenomenon and molecular mechanism of its protective effects on and regeneration of axons.Methods The cortical infarction was induced by photochemistry,termed photothrombotic cortical injury (PCI).Fifteen Sprague Dawley rats were randomly divided into three groups:Sham-operated group,PBS (phosphate buffered solution) group,and s-NgR1-Fc group.In PBS group,PBS was injected into the lateral ventricle of rats; and in sNgR1-Fc group,sNgR1-Fc was injected instead of PBS. The ipsilateral cortex with lesion was harvested for histomorphometry and transmission electron microscope observation 7 days after PCI. Proteins including GTP-RhoA,p-JNK,p-c-JUN and p-ATF-2 were detected by Western blot,as well as Total-J and Total-RhoA.Results The cortical infarction in rats was successfully induced by photochemistry.Compared with sham-operated group,the pathological changes in PBS groups were more serious,including extensive edema or disappearance of axoplasm of fiber without medulla sheath involved and extensive thickening or layer derangement in axoplasm of fiber with medulla sheath involved.These changes were improved significantly after sNgR1-Fc treatment.The levels of GTP-RhoA,p-JNK1,p-JNK2,p-c-JUN and p-ATF-2 in the PBS group were significantly higher than those in the sham-operation group ( P ＜ 0.05 ),whereas the levels of Total-RhoA,Total-JNKl and Total-JNK2 were not different significantly between these two groups (P ＞0.05 ).The sNgR1-Fc treatment up-regulated the levels of these proteins ( P ＜ 0.05 ).Conclusions There is pathological change in axon induced by cerebral hypoxia-ischemia for a long period after cortical infarction.The mechanisms may be associated with RhoA/ROCK/JNK/c-Jun signal way,which is activated by ischemia injury and related to the inhibition of regeneration in axon.Our study shows that NgR1-Fc may inhibit this pathway significantly,and then promote the regeneration of axon partially.