Neuroprotective effects of geranylgeranylacetone in experimental traumatic brain injury

Geranylgeranylacetone (GGA) is an inducer of heat-shock protein 70 (HSP70) that has been used clinically for many years as an antiulcer treatment. It is centrally active after oral administration and is neuroprotective in experimental brain ischemia/stroke models. We examined the effects of single oral GGA before treatment (800 mg/kg, 48 hours before trauma) or after treatment (800 mg/kg, 3 hours after trauma) on long-term functional recovery and histologic outcomes after moderate-level controlled cortical impact, an experimental traumatic brain injury (TBI) model in mice. The GGA pretreatment increased the number of HSP70(+) cells and attenuated posttraumatic alpha-fodrin cleavage, a marker of apoptotic cell death. It also improved sensorimotor performance on a beam walk task; enhanced recovery of cognitive/affective function in the Morris water maze, novel object recognition, and tail-suspension tests; and improved outcomes using a composite neuroscore. Furthermore, GGA pretreatment reduced the lesion size and neuronal loss in the hippocampus, cortex, and thalamus, and decreased microglial activation in the cortex when compared with vehicle-treated TBI controls. Notably, GGA was also effective in a posttreatment paradigm, showing significant improvements in sensorimotor function, and reducing cortical neuronal loss. Given these neuroprotective actions and considering its longstanding clinical use, GGA should be considered for the clinical treatment of TBI.