Characterization of spinal subarachnoid bleeding associated to graded traumatic spinal cord injury in the rat
Study design:Observational study in rats subjected to traumatic spinal cord injury (SCI).Objectives:To describe the features of spinal subarachnoid bleeding (SSB) occurring after graded SCI. SSB after SCI has been reported previously, but has not been studied systematically despite the fact that cerebral subarachnoid bleeding often produces severe neurological damage.Setting:Mexico.Methods:Anesthetized rats were subjected to mild or severe spinal cord contusion at T9. Occurrence, size, progression and location of SSB were characterized morphologically and scored from T7–T12 at 1 h and 1, 3 and 7 days post injury. Besides, contusions were videotaped to visualize bleeding at the moment of impact.Results:SSB started immediately after contusion (severe or mild) and decreased gradually over time. For all vertebral segments, at all time points examined by histology, 48% of areas scored after severe contusion showed bleeding: 25% minor, 17% moderate and 6% major. After mild contusion, only 15% showed bleeding: 13 minor and 2% moderate. Maximum bleeding occurred early after injury in dorsal area of the epicenter in 100% of severe contusions (6% minor, 38 moderate and 56% major), and in 69% of mild contusions (63 minor and 6% moderate).Conclusion:Here, we detail SSB patterns occurring after graded SCI. Further studies are warranted to elucidate the possible role extramedullary events, such as SSB, in the pathophysiology of SCI that might encourage the development of new strategies for its management.