Osteopontin And Spinal Cord Injury

The chemokine osteopontin (OPN) is expressed by microglia as part of inflammatory responses. Although suppression of OPN results in a better outcome in animal models of autoimmune disease, Hashimoto et al. report this week that OPN may be neuroprotective in spinal cord injury.

The authors compared the effects of a spinal cord contusion at T13 in wild-type (WT) and OPN-deficient [knock-out (KO)] mice. At 24 h after contusion, the proinflammatory cytokines TNF (tumor necrosis factor)-:A, interleukin (IL)-1 :A, and IL-6 were downregulated in KO spinal cords according to quantitative real-time PCR, but protein levels were not significantly reduced at 7 d after injury.

Both mRNA and protein levels of the antiapoptotic Bcl-2 were reduced in KO mice. The KO mice performed worse in a locomotor assay 6 weeks after injury and also showed reduced areas of white matter sparing and fewer neurons surrounding the site of impact.



Masayuki Hashimoto, Dongming Sun, Susan R. Rittling, David T. Denhardt, and Wise Young