脊神经节损伤所介导的脊髓背角兴奋性氨基酸和抑制性氨基酸变化的实验研究

The experimental study of the EAAs and IAAs contents changes in the dorsal horn of spinal cord induced by DRG injury

目的研究脊神经节 (DRG)炎性损伤时 ,脊髓背角兴奋性氨基酸 (EAAs)、抑制性氨基酸 (I AAs)含量和脊髓背角谷氨酸 (Glu)、天门冬氨酸 (Asp)免疫组织化学的变化 ,以及与实验动物神经行为异常变化之间的关系。方法健康家兔 5 4只 ,随机分为手术对照组 ( n =2 4) ;炎症损伤组 ( n =2 4)和正常对照组 (n =6)。采用组织氨基酸的含量分析仪测定脊髓背角Glu ,Asp ,GABA ,Tau ,Thr和Ser含量变化。采用免疫组化法观察脊髓背角Glu和Asp分布特点及变化。结果 1.术后 2～ 4周 ,伤侧的Glu ,Asp ,GABA ,Tau ,Ser含量较术前 ,非伤侧显著增高 (P <0 .0 5 )。 2 .术后 2～ 4周 ,其伤侧N 甲基 D 天 (门 )冬氨酸受体 (NMDAR1)免疫阳性纤维在脊髓背角浅层 (Ⅰ ,Ⅱ )和固有层 (Ⅲ ,Ⅳ )的分布密度和染色强度 ,较术前和非伤侧显著降低 (P <0 .0 5 )。结论DRG炎症损伤所介导脊髓背角EAAs释放增加 ,在痛觉过敏的形成和维持中具有重要作用。而IAAs的增加则与机体抗伤害性保护反应相关。DRG炎症损伤初期 ,脊髓背角EAAs/IAAs动态平衡的破坏是伤害性神经细胞兴奋性损伤和伤侧肢体痛觉过敏的主要原因。

ObjectiveTo study the alternations of EAAs, IAAs contents the distribution properties of Glu,Asp immunoreactivity in the dorsal horn of spinal cord and the relations between the abnormal neuro-behavior and the changes induced by inflammatory reaction of DRG. MethodsFifty-four health rabbits were divided into three groups: sham-operative (n=24); inflammatory injury (n=24) and control group( n=6). The tissue content of excitatory (Glu,Asp), inhibitory (GABA,Tau)and neutral (Ser, Thr) amino acids were determined in the dorsal horn of spinal cord (SDH). The distribution features of Glu and Asp was also studied by immunohistochemical analyse.Results The obviously increase of Glu,Asp,GABA,Tau,Ser and NMDAR1 in the injured side of SDH (P<0.05) ConclusionsThe results showed that the increase of EAAs release in SDH induced by inflammatory irritation played an important role in promoting and maintaining hyperalgesia, but increase of IAAs release is mainly related to protective mechanism. The balance of EAAs/IAAs destroyed by inflammatory injury of DRG was a main factor of the hyperexcitotoxicity injury of nociceptive neurons and hyperalgesia development.