INCREASED ORNITHINE DECARBOXYLASE ACTIVITY AND PROTEIN LEVEL IN THE CORTEX FOLLOWING TRAUMATIC BRAIN INJURY IN RATS

There is increasing evidence that the elevated levels of polyamines pl ay an important role in the secondary injury following traumatic brain injury (TBI). Ornithine decarboxylase (ODC) is the rate-limiting enzy me of polyamine biosynthesis. Presently, we measured the ODC protein l evels by Western blot analysis in the cerebral cortex of rats sacrific ed at 2 h, 6 h, 24 h, 72 h and 168 h after controlled cortical impact injury. TBI resulted in a significant increase in ODC protein levels ( 2.5 to 5.5 fold, P < 0.05) and enzyme activity (13 to 21 fold, p < 0.0 1) between 2 and 6 h after the injury. ODC protein levels and enzyme a ctivity returned to normal, control levels by 72 h after the injury. I ncreased ODC protein and enzyme activity could contribute to vasogenic edema and the pathogenesis of neuronal dysfunction after TBI by stimu lating the formation of polyamines. (C) 1998 Elsevier Science B.V.