纳洛酮干预对大鼠弥漫性轴索损伤后突触素表达的影响

The effects of naloxone intervention on the expression of synaptophysin after diffuse axonal injury in rats

目的探讨弥漫性轴索损伤(diffuse axonal injury,DAI)后纳洛酮干预对突触素表达的影响。方法 99只Wistar雄性大鼠随机分为对照组、损伤组、纳洛酮干预组,对照组为假损伤,后两组采用改良的Marmarou大鼠颅脑DAI模型。伤后分别检测突触素表达变化情况,同时评价行为学功能和观察病理变化。结果伤后6 h、24 h,对照组行为学评分显著高于纳洛酮干预组(均P<0.01),同时纳洛酮干预组显著高于损伤组(均P<0.05)。大鼠致伤后,损伤组及纳洛酮干预组基底池、颅底可见轻度蛛网膜下腔出血,但无大面积或局灶性挫裂伤。光镜下见损伤组伤后24 h病理损害最严重,尼氏体数目显著减少、体积变小,甚至溶解消失,纳洛酮干预组上述改变有不同程度减轻。DAI后,突触素免疫阳性反应产物平均积分光密度(IOD)值分析表明:对照组IOD值高于损伤组(P<0.01)及纳洛酮干预组(P<0.05);损伤组DAI后突触素表达下降,24 h表现最为明显(P<0.01);纳洛酮干预组表达下降程度减轻,伤后6～72 h突触素表达显著高于损伤组(P<0.05),且24 h差异最明显(P<0.01)。结论早期纳洛酮干预对DAI后大鼠有一定保护作用,可能通过调节突触素表达而实现的。

Objective To explore the effect of naloxone intervention on the expression of synaptophysin（Syn） after diffuse axonal injury（DAI） in rats.Methods Ninety-nine male Wistar rats were randomly divided into control,injury and naloxone intervention groups.The rats were sham-operated in control group.The DAI models were established by modified Marmarou method in the latter two groups.The neurological scores（NS）,pathological changes and expression of Syn in the brain tissue were observed after DAI.Results NS was significantly higher in control group than in naloxone intervention group（P0.01） where NS was significantly higher than in injury group 6 and 24 hours after the injury（P0.05）.Mild subarachnoid hemorrhage was observed in the basal cistern and skull base both in injury group and intervention group without extensive or focal contusion.The pathological damages were found to be the most serious 24 h after injury in injury group under light microscope in which the number and volume of Nissl bodies significantly reduced,or Nissl bodies even dissolved and disappeared.These changes were alleviated in naloxone intervention group.Mean integrated optical density（IOD） value analysis of Syn immunoreactive product showed that IOD in control group was higher than that in injury（P0.01） and naloxone intervention groups（P0.05）.The expression of Syn in injury group decreased after DAI and was lowest 24 h after DAI（P0.01）.The down-regulation extent of Syn expression was reduced in naloxone intervention group and the expression of Syn was significantly higher than that in injury group from 6 h to 72 h after DAI（P0.05） and the difference became most obvious 24 h after DAI（P0.01）.Conclusions Early naloxone intervention can protect rat from DAI,which may be partly accomplished through regulating the expression of Syn.