东莨菪硷对兔急性脑损伤保护作用的实验研究

Protective effects of scopolamine on rabbits with acute brain injury

目的 :研究M受体拮抗剂东莨菪硷对兔急性脑损伤的保护作用 ,并初步探讨乙酰胆碱 (ACh)在创伤性脑伤早期病理变化中的作用。方法 :用自由落体打击器制作兔脑外伤模型 ,并于伤后 5min ,2h腹腔注射东莨菪硷 ,用经颅多谱勒监测大脑中动脉血流速度和搏动指数的变化 ;取脑组织检测Ca2 +、伊文思蓝 (EB)、超氧化物歧化酶 (SOD)、丙二醛 (MDA) ,并作病理检查。结果 :病检证实本模型符合临床所见加速性脑损伤的病理变化 ,东莨菪硷可降低兔脑外伤后脑组织中Ca2 +,MDA ,EB含量 ,升高SOD ,增加脑血流。结论 :脑外伤后早期ACh可致神经元钙超载、氧自由基反应、脑血管痉挛和血脑屏障 (BBB)通透性增强 ,M受体拮抗剂东莨菪硷可改善这些病理变化 。

Objective To study the protective effects of scopolamine (Sco) (a muscarinic receptor antagonist) on rabbits with acute brain injury, and preliminarily explore the roles of acetylcholine (ACh) in the early pathologic changes of traumatic brain injury(TBI). Methods The model of acute brain injury was established by a free-falling device, and the rabbits received Sco intraperitoneally at 5 minutes and 2 hours after brain injury respectively. Transcranial Doppler (TCD) was used to monitor cerebral blood flow velocity (CBV) and pulsatility index (PI) of middle cerebral artery (MCA). The levels of Ca 2+ , the activities of superoxide dismutase (SOD), the contents of malondiadehyde (MDA) and Evans blue (EB) were measured, and the pathological changes were observed in brain tissue. Results This model consisted with the pathologic changes of accelerated brain injury. Sco reduced the levels of Ca 2+ , EB and MDA, increased the activities of SOD, and improved cerebral blood flow following brain injury. Conclusions In the early stage of brain injury, ACh can cause neuron calcium overload, oxide free radical reaction, cerebral vasospasm, and increase blood-brain barry(BBB) permeability. Scopolamine, a muscarinic receptor antagonist, can improve these pathologic changes. As a result, Sco has protective effects on brain tissue injury.