Golding E M, Contant C F, Robertson C S, Bryan R M
Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA.
J Neurotrauma. 1998 Nov;15(11):973-84. doi: 10.1089/neu.1998.15.973.
The present study examined the effect of severe traumatic brain injury (TBI) on the myogenic response in the rat middle cerebral artery (MCA). Rats were subjected to severe controlled cortical impact (CCI; 5 m/sec, 130-msec duration, 3-mm deformation) injury over the right parietal cortex. At 2, 24, and 120 h postinjury, ipsilateral and contralateral segments of MCAs were isolated, mounted in a vessel chamber, and pressurized. After equilibration, the myogenic tone, the difference in vessel diameter in the presence and absence of calcium for a given pressure, and the myogenic response (the active contractile response elicited by a vessel to increasing pressure), were measured. At 24 h postsurgery, there was a significant interaction between myogenic tone and pressure in the ipsilateral and contralateral MCAs when TBI was compared to shams. However, this was not apparent, at the 2- and 120-h time points. At 2- and 24-h postsurgery, there was a significant interaction between myogenic response and pressure in the ipsilateral MCAs when TBI was compared to shams. While the response of the vascular smooth muscle was altered following injury, it was still functioning, suggesting that these vessels compensate, perhaps through alternate mechanisms or by relying on those remaining intact mechanisms.
本研究考察了重度创伤性脑损伤（TBI）对大鼠大脑中动脉（MCA）肌源性反应的影响。对大鼠右侧顶叶皮层施加重度控制性皮质撞击（CCI；5米/秒，持续130毫秒，3毫米变形）损伤。在损伤后2小时、24小时和120小时，分离MCA的同侧和对侧节段，安装在血管腔室中并加压。平衡后，测量肌源性张力、给定压力下有钙和无钙时血管直径的差异以及肌源性反应（血管对压力增加产生的主动收缩反应）。与假手术组相比，在术后24小时，TBI大鼠同侧和对侧MCA的肌源性张力与压力之间存在显著交互作用。然而，在2小时和120小时时间点，这种情况并不明显。与假手术组相比，在术后2小时和24小时，TBI大鼠同侧MCA的肌源性反应与压力之间存在显著交互作用。虽然损伤后血管平滑肌的反应发生了改变，但它仍在发挥作用，这表明这些血管可能通过替代机制或依靠那些保持完整的机制进行代偿。
