Expression and role of type I collagen in a rat spinal cord contusion injury model

To verify the expression of type I collagen after SCI and discuss its role and cellular origin, a standardized animal model of contusive spinal cord injury (SCI) was analyzed. Male Sprague-Dawley rats were injured at T11/12 and sacrificed at 1, 4 and 8 weeks after injury. The spinal cord was removed en block for both Western blotting and RT-PCR in order to verify expression of type I collagen. For immunohistological examination, those sections were stained with anti-type I collagen, RECA-1 and anti-rat prolyl-4-hydroxylase. Double-labeling immunohistochemistry was performed using anti-type I collagen and RECA-1. Those sections were examined with an electron microscope. Western blots for type I collagen were positive, as was the gene expression of type I collagen mRNA. Type I collagen after SCI was observed around blood vessels in the ventral white matter of the spinal cord 4 weeks after injury in double-labeling immunohistological examination and electron microscopic images. Immunohistochemical expression of fibroblast was increased 4 weeks after injury. This study revealed the post-SCI expression of type I collagen around blood vessels. Type I collagen may play a role in angiogenesis after SCI. Fibroblasts may produce type I collagen in rat spinal cord.