2006 merck/merial - School of Veterinary Medicine - Louisiana State ...

and detrimental impacts on the brain after injury. Thus, it is important to follow the time course of CNS insults, such as thosecaused by stereotaxic techniques and ensuing glial activation. Expression of GFAP (glial fibrillary acidic protein), anastrocyte-specific marker, is activation dependent. Here, we have utilized a unique transgenic mouse model, FVB GFAP-luc,and bioluminescence imaging, to continuously monitor in vivo GFAP expression levels in the brains of mice that haveundergone stereotaxic manipulation. Mice were injected uni- or bilaterally with 6-OHDA or ascorbic acid (AA) control underanesthesia. Mice were imaged post-operatively for up to 21 days using Xenogen’s IVIS Bioluminescence Imaging set-up andLiving Image software to monitor GFAP expression. At the end of live imaging, brains were dissected, ex vivo brain imageswere obtained, and brain tissues prepared for analyses. We have observed that (i) both AA and 6-OHDA markedly enhanceGFAP expression and (ii) the increased expression is greatest during the first week after injury, but is still present at 3 weeksafter injury. This data was confirmed with Western blot analysis for GFAP. Thus, it appears that (i) bioluminescenceimaging is a useful tool for monitoring glial response to injury and (ii) in these mice, astrocytic activation depends mostly onthe mechanical aspects of injury. Supported by ES11654 (NIH) and T35RR07071 (NIH).142