Secondary spinal cord hypoperfusion of circumscribed areas after injury in rats

Abstract

Objectives: The evaluation of the spatial spread of ischemia following spinal cord injury (SCI) is important for planning therapeutic strategies for secondary injury. The purpose of this study was to investigate in detail the change in regional spinal cord blood flow (rSCBF) after SCI.Methods: Thirty-four male Wistar rats were used, for which laminectomies of the T11–13 vertebrae were performed. SCI was produced by a directed impact through a laminectomy site at the level of the Th12 using a pneumatic impact device. We measured the sequential and spatial changes of rSCBF using a laser Doppler scanning technique before and after SCI in rats not only at the injured myelomere but also at the circumferent myelomeres. SCBF mapping was carried out before and after SCI on each site.Results: After SCI, the rSCBF value gradually decreased for each site for the SCI group (n=26), while it globally decreased at the epicenter. Moreover, a decrease in SCBF was observed at the caudal and rostral sites. The mean value of the %SCBF 120 minutes after SCI for each site was 63.6±2.3% (Th11), 74.4±4.5% (Th12), 75.8±3.2% (Th13), and was significantly lower for the rostral site compared with the caudal site (p<0.05, one-way analysis of variance).Discussion: This study found that SCBF is significantly decreased not only at the injured myelomere but also at the circumferent myelomeres. Circumferentially extending ischemia after SCI is related to secondary injury after SCI. The improvement in SCBF after SCI, therefore, can be attributed to the treatment of SCI.