Department Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky 40292, USA.
J Neurotrauma. 2012 Oct 10;29(15):2490-8. doi: 10.1089/neu.2012.2402. Epub 2012 Aug 27.
Polyuria contributes to bladder overdistention, which confounds both lower and upper urinary tract management in individuals having a spinal cord injury (SCI). Bladder overdistention post-SCI is one of the most common triggers for autonomic dysreflexia, a potentially life-threatening condition. Post-SCI polyuria is thought to result from loss of vascular tone in the lower extremities, leading to edema and subsequent excess fluid, resulting in polyuria. Mild SCIs that have near complete recovery would therefore be expected to have little to no polyuria, while severe injuries resulting in flaccid limbs and lower extremity edema would be expected to exhibit severe polyuria. Since interventions that may decrease lower extremity edema are recommended to lessen the severity of polyuria, step training (which promotes vascular circulation) was evaluated as a therapy to reduce post-SCI polyuria. In the present study, polyuria was evaluated in mild, moderate, and severe contusive SCI in adult male rats. The animals were housed in metabolic cages for 24-hour periods pre- and post-SCI (to 6 weeks). Urine, feces, food, water, and body weights were collected. Other assessments included residual expressed urine volumes, locomotor scoring, in-cage activity, and lesion histology. SCI produced an immediate increase in 24-hour urine collection, as early as 3 days post-SCI. Approximately 2.6-fold increases in urine collection occurred from weeks 1-6 post-SCI for all injury severities. Even with substantial gains in locomotor and bladder function following a mild SCI, polyuria remained severe. Step training (30 min/day, 6 days/week) did not alleviate polyuria in the moderate SCI contusion group. These results indicate that (1) mild injuries retaining weight-bearing locomotion that should have mild, if any, edema/loss of vascular tone still exhibit severe polyuria, and (2) step training was unable to reduce post-SCI polyuria. Taken together, these results indicate that the current mechanistic hypothesis of post-SCI polyuria may be incomplete.
多尿导致膀胱过度充盈，这使得脊髓损伤（SCI）患者的下尿路和上尿路管理都变得复杂。SCI 后膀胱过度充盈是自主反射异常的最常见触发因素之一，这是一种潜在的危及生命的情况。SCI 后多尿被认为是下肢血管张力丧失的结果，导致水肿和随后的过多液体，导致多尿。因此，预计近乎完全恢复的轻度 SCI 几乎没有多尿，而导致弛缓性四肢和下肢水肿的严重损伤则预计会出现严重的多尿。由于建议进行可能减少下肢水肿的干预措施以减轻多尿的严重程度，因此评估了阶梯训练（促进血管循环）作为减少 SCI 后多尿的一种治疗方法。在本研究中，评估了成年雄性大鼠的轻度、中度和重度挫伤性 SCI 中的多尿。动物在 SCI 前和 SCI 后（6 周）的 24 小时内被安置在代谢笼中。收集尿液、粪便、食物、水和体重。其他评估包括残余表达的尿量、运动评分、笼内活动和损伤组织学。SCI 导致 24 小时尿液收集立即增加，早在 SCI 后 3 天即可观察到。所有损伤严重程度的 SCI 后第 1-6 周，尿液收集量增加约 2.6 倍。即使轻度 SCI 后运动和膀胱功能有显著改善，多尿仍严重。阶梯训练（每天 30 分钟，每周 6 天）并未减轻中度 SCI 挫伤组的多尿。这些结果表明：（1）保留负重运动能力的轻度损伤，即使有任何水肿/血管张力丧失，仍表现出严重的多尿；（2）阶梯训练不能减少 SCI 后的多尿。总之，这些结果表明，SCI 后多尿的当前机制假说可能不完整。
