Histological Analysis of Spinal Cord Injury

Sections of the spinal cord and brain were analyzed by hematoxylin and eosin (H&E) and immunohistochemical staining. The rats were perfused with 0.9% normal saline, followed by 4% paraformaldehyde (Hushi Inc., Shanghai, China) in 0.1 M PBS (pH 7.4). The brains and spinal cords were dissected from the rats, postfixed overnight in 4% paraformaldehyde at 4 °C, and cryopreserved with 30% sucrose for 3 days. The tissue samples were embedded in the M1 compound (Thermo Fisher Scientific Inc., Waltham, MA, USA), the spinal cords were cut into 16 µm sagittal sections, and the brain samples were cut into 10 µm coronal sections using a cryotome cryostat. H&E staining was performed on the lesion epicenter to examine the general morphology of the spinal cord at 12 weeks after injury, and three sagittal sections containing a lesion cavity and four cases per group were evaluated for quantitative analysis. The size of the lesion cavity was manually outlined for each section under confocal microscopy and analyzed using Image J software (1.37 v, National Institutes of Health, Bethesda, MD, USA) as our previous studies [28 (link),29 (link)].