Primary pathological changes of spinal cord tissues of human complete spinal cord injury and their significance

Abstract

Objective To investigate the pathological changes of spinal cord tissues after spinal cord injury and their significance for clinical diagnosis and treatment of complete spinal cord injury. Methods Patients with complete spinal cord injury were selected. After rigorous ethical review and patient informed consent, damaged section of the spinal cord and necrotic tissue were removed and transplanted with the function biological material with autologous stem cell. The specimen of injured spinal cord collected during the operation were divided into three phases according to injury time: 3 cases of acute phase (≤3 days), 3 cases of subacute phase (4-14 days), and 1 case of chronic phase (>14 days). The pathological changes of injured spinal cord tissue were observed through HE staining, and the expression of hypoxia inducible factor 1α (HIF-1α), tumor necrosis factor (TNF-α), microtubule-associated protein(MAP2)were detected by immunofluorescence. Results (1) HE staining showed that the acute injury mainly manifested as diffuse hyperemia and liquefaction, subacute injury infiltration of inflammatory cells and spinal cord liquefaction, and chronic injury mainly scar repair. (2)The fluorescence intensity (24.67±0.51) of HIF-1α in chronic injury was higher than acute (3.17±0.40) and subacute injury (4.62±0.48) (P<0.05), and the fluorescence intensity of subacute injury was higher than that of acute injury (P<0.05). (3) The fluorescence intensity (17.60±1.17) of TNF-α in subacute injury was higher than that of acute injury (5.35±0.33) and chronic injury (1.81±0.17) (P<0.05); (4) The fluorescence intensity of MAP2 was 9.46±0.41 in acute injury, higher than 3.25±0.42 in subacute injury and 1.16±0.08 in chronic injury (P<0.05). Conclusions There are hypoxia, inflammation, neuronal apoptosis and repair in the spinal cord tissues after complete spinal cord injury, such as hyperemia, liquefaction, necrosis and gradual scar repair. The severity of inflammation and hypoxia significantly differs among different injury phases. The inflammatory cytokines are mainly active in the microenvironment during subacute injury. Hypoxia is mainly involved in the pathological changes of chronic injury. This can provide a new theoretical basis for the clinical treatment of complete spinal cord injury and the timing of surgical treatment. Key words: Spinal cord injuries; Pathology, surgical; Immunohistochemistry