Blast traumatic brain injury induced cognitive deficits are attenuated by pre- or post-injury treatment with the glucagon-like peptide-1 receptor agonist, exendin-4 [Day 3 dataset]. Mus musculus

Blast traumatic brain injury (B-TBI) affects military and civilian personnel. Presently there are no approved drugs for blast brain injury. Exendin-4, administered subcutaneously, was evaluated as a pre-treatment (48 hours) and post-injury treatment (2 hours) on neurodegeneration, behaviors and gene expressions in a murine open field model of blast injury. B-TBI induced neurodegeneration, changes in cognition and genes expressions linked to dementia disorders. Exendin-4, administered pre- or post-injury ameliorated B-TBI-induced neurodegeneration at 72 hours, memory deficits from days 7-14 and attenuated genes regulated by blast at day 14 post-injury. The present data suggest shared pathological processes between concussive and B-TBI, with endpoints amenable to beneficial therapeutic manipulation by exendin-4. B-TBI-induced dementia-related gene pathways and cognitive deficits in mice somewhat parallel epidemiological studies of Barnes and co-workers who identified a greater risk in US military veterans who experienced diverse TBIs, for dementia in later life. Overall design: Experimental conditions used to create a blast traumatic brain injury (B-TBI) and the subsequent model characterization have been described in detail previously. In short, male ICR mice (30-40 g) were anaesthetized with a combination of ketamine (100 mg/kg) and xylazine (10 mg/kg). Once fully anaesthetized, the animals were positioned ‘side-on’ to the blast overpressure on an elevated platform in a circle, 7 meters from the source of the detonation generated by the detonation of 500 g of trinitrotoluene (TNT). The maximum overpressure generated by the detonation was 2.5 PSI (17.23 kPa). The following animal treatment groups were utilized: sham operated no blast (Sham); blast traumatic brain injury (B-TBI); Ex-4 as a pre-treatment to the blast injury (Ex-4/B-TBI); Ex-4 as a post-treatment to the blast injury (B-TBI/Ex-4) and Ex-4 but no injury (Ex-4). Hippocampal brain gene expression was examined on day 3 and day 14 (Experiment GSE44625) after the blast traumatic brain injury (B-TBI) or sham procedure. Animals received 3.5 pM/kg/min (21ug/kg/day) Exendin-4 using Alzet micro-osmotic pumps either as a pre-treatment to the blast injury 48 hours before (Ex-4 pre-TBI) or as a post-treatment 2 hours after the blast injury (Ex-4 post-TBI). Animals in a previous data set on Day 14 (GSE44625) were administered Ex-4 as a pre-treatment.