Baine Rachel E, Johnston David T, Strain Misty M, Henwood Melissa K, Davis Jacob A, Reynolds Joshua A, Giles Erin D, Grau James W
Department of Psychological and Brain Sciences, Texas A&M University, College Station, Texas, USA.
Department of Cellular and Integrative Physiology, University of Texas Health Science, San Antonio, Texas, USA.
Neurotrauma Rep. 2022 Jan 31;3(1):70-86. doi: 10.1089/neur.2021.0055. eCollection 2022.
Spinal cord injuries (SCIs) are often the result of traumatic accidents, which also produce multiple other injuries (polytrauma). Nociceptive input from associated injuries has been shown to significantly impair recovery post-SCI. Historically, work in our laboratory has focused exclusively on male animals; however, increasing incidence of SCI in females requires research to determine whether pain (nociceptive) input poses the same risk to their recovery. Some animal studies have shown that females demonstrate greater tissue preservation and better locomotor recovery post-SCI. Given this, we examined the effect of sex on SCI recovery in two pain models-intermittent electrical stimulation (shock) to the tail or capsaicin injection to the hindpaw. Female rats received a lower thoracic contusion injury and were exposed to noxious stimulation the next day. The acute effect of noxious input on cardiovascular function, locomotor performance, and hemorrhage were assessed. Treatment with capsaicin or noxious electrical stimulation disrupted locomotor performance, increased blood pressure, and disrupted stepping. Additional experiments examined the long-term consequences of noxious input, demonstrating that both noxious electrical stimulation and capsaicin impair long-term recovery in female rats. Interestingly, injury had a greater effect on behavioral performance when progesterone and estrogen were low (metestrus). Conversely, nociceptive input led to a greater disruption in locomotor performance and produced a greater rise in blood pressure in animals injured during estrus.
脊髓损伤（SCI）通常是创伤性事故的结果，这类事故还会导致多种其他损伤（多发伤）。研究表明，相关损伤产生的伤害性输入会显著损害脊髓损伤后的恢复。从历史上看，我们实验室的工作一直只专注于雄性动物；然而，女性脊髓损伤发病率的上升要求开展研究，以确定疼痛（伤害性）输入对其恢复是否构成同样的风险。一些动物研究表明，雌性动物在脊髓损伤后表现出更好的组织保存和运动功能恢复。鉴于此，我们在两种疼痛模型中研究了性别对脊髓损伤恢复的影响，即对尾巴进行间歇性电刺激（电击）或在后爪注射辣椒素。雌性大鼠接受下胸段挫伤，第二天接受有害刺激。评估了有害输入对心血管功能、运动能力和出血的急性影响。辣椒素或有害电刺激处理会破坏运动能力、升高血压并干扰步态。其他实验研究了有害输入的长期后果，结果表明有害电刺激和辣椒素都会损害雌性大鼠的长期恢复。有趣的是，当孕酮和雌激素水平较低（动情后期）时，损伤对行为表现的影响更大。相反，伤害性输入会导致运动能力受到更大干扰，并使处于发情期受伤的动物血压升得更高。
