Center for Brain and Spinal Cord Repair, Neuroscience Graduate Studies Program, The Ohio State University, Columbus, OH, USA.
Exp Neurol. 2010 Oct;225(2):366-76. doi: 10.1016/j.expneurol.2010.07.009. Epub 2010 Jul 17.
Spinal cord injury (SCI) impairs sensory systems causing allodynia. Measuring the development of allodynia in rodent models of SCI is challenging due to spinal shock and marked motor impairments. Assessment of SCI-induced allodynia is not standardized across labs, making interpretation of results difficult. Therefore, we validated sensory threshold assessment after SCI and developed a novel assessment of allodynia prior to motor recovery in a rat SCI model. One hundred fifty-six Sprague-Dawley rats received T8 laminectomy or mild to moderate SCI using the OSU SCI device (0.3 mm to 1.3 mm cord displacement). To determine tactile thresholds, von Frey hairs (VFH) were applied in Up-Down or ascending order to the dorsal or plantar hindpaw. The most efficient and valid procedures that maintain high sensitivity and specificity were identified. Ten Up-Down VFH applications yielded stable thresholds; reducing the risk of threshold decay and unnecessary exposure to painful stimuli. Importantly, distraction of SCI-rats with food revealed differential decay of thresholds than when distraction is not provided. The new test uses dorsal VFH stimulation and is independent of trunk or hindlimb control. Acute dorsal VFH thresholds collected before recovery of hindlimb weight support accurately predicted plantar VFH thresholds measured at late timepoints (chi(2)=8.479; p<0.05). Thus, standardized testing early after SCI using the dorsal VFH test or later using 10 stimuli in the Up-Down test produces valid measures of tactile sensation across many SCI severities. Early detection of allodynia in experimental SCI will allow identification of mechanisms responsible for pain development and determine targets for therapeutic interventions.
脊髓损伤 (SCI) 会损害感觉系统，导致痛觉过敏。由于脊髓休克和明显的运动障碍，在 SCI 的啮齿动物模型中测量痛觉过敏的发展具有挑战性。由于不同实验室之间的评估标准不统一，使得结果的解释变得困难。因此，我们验证了 SCI 后感觉阈值评估，并在大鼠 SCI 模型中在运动恢复之前开发了一种新的痛觉过敏评估方法。156 只 Sprague-Dawley 大鼠接受 T8 椎板切除术或使用 OSU SCI 装置进行轻度至中度 SCI（脊髓位移 0.3 毫米至 1.3 毫米）。为了确定触觉阈值，使用 Von Frey 毛发 (VFH) 以上下或递增顺序施加于后足底或足底后足。确定了最有效和最有效的程序，这些程序保持了高灵敏度和特异性。10 次上下 VFH 应用产生稳定的阈值；降低了阈值衰减和不必要暴露于疼痛刺激的风险。重要的是，用食物分散 SCI 大鼠的注意力会导致阈值衰减不同于不提供注意力分散的情况。新测试使用背侧 VFH 刺激，且不依赖于躯干或后肢控制。在恢复后肢承重之前收集的急性背侧 VFH 阈值准确预测了在晚期测量的足底 VFH 阈值（卡方 (chi(2))=8.479；p<0.05）。因此，使用背侧 VFH 测试在 SCI 后早期进行标准化测试，或在晚期使用 Up-Down 测试中的 10 个刺激进行测试，可以在许多 SCI 严重程度下产生有效的触觉感觉测量。在实验性 SCI 中早期检测痛觉过敏将允许识别负责疼痛发展的机制，并确定治疗干预的目标。
