Gruner J A, Yee A K, Blight A R
Cephalon Inc., Department of Experimental Pharmacology, West Chester, PA 19380-4245, USA.
Brain Res. 1996 Aug 5;729(1):90-101.
Most experimental spinal cord injury studies described to date have relied on a limited number of injury gradations, and have tacitly assumed that outcome (functional, histological, and/or neurophysiological) is a monotonically graded function of injury severity. In contrast, the present study provides evidence that functional and morphological outcome after spinal cord compression injury may occur in a discontinuous, non-graded manner in response to linearly graded injury levels. The thoracic spinal cord of adult rats was transiently compressed to thicknesses from 1.8 to 0.8 mm in 0.2 mm steps, or sham injury was administered. Open field motor behavior and segmental reflexes were evaluated up to 21 days post injury and correlated with histological measures and injury level. The highest correlation was between histological outcome and open field motor scores. Among the six injury groups, only three significantly different outcomes were apparent in the open field, reflex, and histological measures, consisting of the injury group pairs 1.8/1.6, 1.4/1.2, and 1.0/0.8 mm. At day 21, the 1.8/1.6 mm injury groups were also indistinguishable from the sham injury group. The implications of these findings in terms of therapeutic studies are discussed. Comparison of the temporal outcome patterns among contusion and compression injuries in rats and other species also revealed a significant species difference: a period of delayed or secondary functional loss reported in the guinea pig was not present in the rat.
迄今为止所描述的大多数实验性脊髓损伤研究都依赖于有限数量的损伤分级，并且默认结果（功能、组织学和/或神经生理学）是损伤严重程度的单调分级函数。相比之下，本研究提供了证据表明，脊髓压迫性损伤后的功能和形态学结果可能以不连续、非分级的方式出现，以响应线性分级的损伤水平。成年大鼠的胸段脊髓被短暂压缩至厚度从1.8毫米到0.8毫米，以0.2毫米的步长递减，或进行假手术损伤。在损伤后长达21天评估旷场运动行为和节段性反射，并将其与组织学测量结果和损伤水平相关联。组织学结果与旷场运动评分之间的相关性最高。在六个损伤组中，在旷场、反射和组织学测量中仅出现了三个明显不同的结果，分别由损伤组对1.8/1.6、1.4/1.2和1.0/并0.8毫米组成。在第21天，1.8/1.6毫米损伤组与假手术损伤组也没有区别。讨论了这些发现在治疗研究方面的意义。对大鼠和其他物种的挫伤和压迫性损伤的时间结果模式进行比较还揭示了一个显著的物种差异：豚鼠中报道的延迟或继发性功能丧失期在大鼠中不存在。
