Iizuka H, Sakatani K, Young W
Department of Neurosurgery, New York University Medical Center, NY 10016.
Stroke. 1989 Oct;20(10):1396-402. doi: 10.1161/01.str.20.10.1396.
We used the Fink-Heimer method to study degenerating corticofugal axons after unilateral middle cerebral artery occlusion in 14 adult male Long-Evans hooded rats. Axonal degeneration in the pyramidal tracts was prominent at 1-3 weeks, manifesting in well-defined silver-impregnated axonal bundles coursing from the internal capsule to the pyramids and crossing completely to the contralateral spinal cord. In half of eight rats examined at 1-3 weeks, the cortical infarct included the forelimb region of the sensorimotor cortex, and degenerating corticospinal axons could be traced to the lower cervical segments; in rats with involvement of the hindlimb cortical area as well, axonal degeneration extended to the lumbosacral segments. Terminal degeneration products were present in the forebrain, midbrain, and brainstem within 2 days after arterial occlusion; the number of degenerating terminals peaked at 7 days and decreased gradually thereafter up to 6 weeks. Dense terminal degeneration was observed in the trigeminal nuclear complex of all seven rats studied at 2 and 7 days. In these seven rats, five had small cortical infarcts, and silver-impregnated terminals were observed in the lateral reticular formation; in two rats with large cortical lesions, terminal degeneration was prominent in the medial reticular formation as well. We conclude that infarcts produced by middle cerebral artery occlusion cause axonal degeneration in the brainstem and spinal cord. The Fink-Heimer method may be useful for evaluating the rat middle cerebral artery occlusion model.
我们采用芬克-海默法研究了14只成年雄性长-伊文斯戴帽大鼠单侧大脑中动脉闭塞后皮质传出轴突的退变情况。锥体束的轴突退变在1至3周时较为明显，表现为从内囊延伸至锥体并完全交叉至对侧脊髓的界限清晰的银染轴突束。在1至3周检查的8只大鼠中，有一半的皮质梗死包括感觉运动皮质的前肢区域，退变的皮质脊髓轴突可追踪至下颈段；在同时累及后肢皮质区域的大鼠中，轴突退变延伸至腰骶段。动脉闭塞后2天内，前脑、中脑和脑干出现终末退变产物；退变终末的数量在7天时达到峰值，此后逐渐减少直至6周。在2天和7天研究的所有7只大鼠的三叉神经核复合体中均观察到密集的终末退变。在这7只大鼠中，5只有小的皮质梗死，在外侧网状结构中观察到银染终末；在2只有大的皮质病变的大鼠中，内侧网状结构中也有明显的终末退变。我们得出结论，大脑中动脉闭塞产生的梗死导致脑干和脊髓的轴突退变。芬克-海默法可能有助于评估大鼠大脑中动脉闭塞模型。
