Systemic Microcirculation after Complete High and Low Thoracic Spinal Cord Section in Rats

Abstract

Spinal cord injury (SCI) produces multiple systemic and metabolic alterations. Although some systemic alterations could be associated with ischemic organ damage, little is known about microvascular blood flow (MVBF) in organs other than the spinal cord after acute SCI. We used laser Doppler flowmetry in anesthetized rats to assess MVBF in several tissues before and after complete T-2 and T-9 SCI at 1 h and on days 1, 3, and 7 post-SCI. Mean arterial blood pressure (MAP), heart rate and hematologic variables also were recorded. MAP changes after T-2 injury were not significant, while MAP decreased significantly 1 h after T-9 injury. Statistically significant bradycardia occurred after T-2 injury at 7 days; statistically significant tachycardia occurred after T-9 injury at 1, 3, and 7 days. Hematocrit significantly increased at day 1 and decreased at days 3 and 7 after T-2 injury. SCI was associated with significant decreases in MVBF in liver, spleen, muscle and fore footpad skin. Changes in MVBF in hind footpad skin and kidney were not significant. Changes were more pronounced at 1 h and 1 day post-SCI. Significant differences between MVBF after T-2 and T-9 SCI occurred only in liver. MVBF significantly correlated with regional peripheral vascular resistances (assessed using the MAP/MVBF ratio), but not with MAP. In conclusion, organ-specific changes in systemic MVBF that are influenced by the level of SCI, could contribute to organ dysfunction.

Hormonal And Immunological Changes in Mice after Spinal Cord Injury

“…This may explain why mice displayed only moderate changes of hematocrit and hemoglobin levels post-Tx, given that experimentally and traumatically induced SCI are not entirely comparable. Supporting this, no significant change of hematocrit and erythrocyte levels were reported after 1 week in experimentally induced paraplegic rats (Guizar-Sahagun et al, 2004). Additional reasons for mild anemia in chronic patients include nutritional, gastrointestinal, and autonomic dysreflexia-related problems (Perkash and Brown, 1986).…”

Early Administration of l-Arginine in Experimental Acute Spinal Cord Injury Impairs Long-Term Motor Function Recovery

“…1 These alterations are associated with organ dysfunction and altered drug disposition. 2 The circulatory damage to the SC starts with blood vessel rupture occurring at the moment of impact, which is followed by vascular thrombosis, compression, and vasospasm. 3 The resultant posttraumatic cord ischemia occurs not only at the injured site but also rostral and caudal to it.…”

Acute Spinal Cord Injury Induces Genetic Damage in Multiple Organs of Rats

“…1). Some studies have provided evidences that the disruption of the autonomic nervous system results in hemodynamic changes Guizar-Sahagun et al 2004) that can lead to delays in operative intervention after SCI (Illman et al 2000) and may worsen long-term outcome by reducing spinal cord blood flow. Besides, spinal cord blood flow is already compromised by several vascular mechanisms, including primary injury to microvessels, intraluminal thrombosis, vasospasm, compression, edema, and endothelial injury (Claydon et al 2006).…”