Establishment of rat model of impact spinal cord injury and pathological observations / 中华创伤杂志

ABSTRACT

Objective To establish rat model of impact spinal cord injury, observe the pathological changes of the model and assess its stability, reproducibility and consistency. Methods Moderate and severe spinal cord injury (SCI) models were established by using modified weight drop device. The pathological and functional changes after SCI were observed by means of BBB scoring, electrophysiology,immunohistochemistry and electronic microscopy so as to estimate the reproducibility of rat models and their consistency with severity of SCI. Results Locomotion and nerve impulse transduction along the spinal cord measured by motorial and sensory evoked potentials recovered gradually over time after SCI.However, the recovery rate of moderate SCI group was better than that of severe SCI group. Histological and immunohistochemical experiments showed that the glial scar as well as cavity were formed after SCI.Whereas, compared with moderate SCI group, the injury of severe SCI group was severer, with less spared tissue. Electronic microscopic observation displayed that hemorrhage, edema, neutrophilic granulocytic infiltration and chromatin margination of glia arose at day 1 after SCI. Vacuolization of mitochondria, degeneration of axon with edema could be seen at 2 weeks after injury. Degeneration of myelin and deposition of collagen fibril emerged at 8 weeks postinjury. Conclusions The rat models of impact SCI established in this study can distinguish the graded injury, and significantly correlate with the behavioral,electrophysiological and pathological outcomes, which indicates that the models possess good stability, reproducibility and consistency. Glial scar with cavity marked by GFAP or Vimentin is the pathological hallmark after SCI, and thereby GFAP or Vimentin can be used as a marker for demarcate the border of glial scar.