Am J Pathol. 2003 Sep;163(3):1069-80
Weerth SH, Rus H, Shin ML, Raine CS.
Department of Pathology (Neuropathology), F140, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Activation of the classical complement system is known to play a central role in autoimmune demyelination.
We have analyzed the role of complement component C5 in experimental autoimmune encephalomyelitis (EAE) using C5-deficient (C5-d) and C5-sufficient (C5-s) mice.
Both groups of mice displayed early onset EAE, a short recovery phase, and similar stable chronic courses.
However, in contrast to the clinical similarities, marked differences were apparent by histopathology.
During acute EAE in C5-d, a delay in inflammatory cell infiltration and tissue damage was observed along with restricted lesion areas, which in C5-s mice were more extensive and diffuse.
More striking were the differences in chronic lesions.
In C5-d mice, inflammatory demyelination and Wallerian degeneration were followed by axonal depletion and severe gliosis, while in C5-s, the same initial signs were followed by axonal sparing and extensive remyelination.
In C5-d, immunohistochemistry and Western blotting showed an increase in glial fibrillary acidic protein and a decrease in neurofilament protein, proteolipid protein, and several pro-inflammatory markers.
These results in the EAE model indicate that absence of C5 resulted in fiber loss and extensive scarring, whereas presence of C5-favored axonal survival and more efficient remyelination.