The perfect CBD:THC balance prevents seizures and aids brain injury recovery

An optimal ratio of cannabidiol (CBD) to tetrahydrocanabinol (THC) was hypothesized to protect against neuropathological consequences following traumatic brain injury (TBI). Varied CBD:THC extract concentrations were compared with hemp CBD lacking THC (CBD0). Neurons, glia, and parvalbumin interneurons (PV-INs) were evaluated. Weight loss was observed following high doses of THC dominant cannabis, THC100:1. Neuroscores and vestibulomotor performance were restored most with CBD:THC300:1-10:1. However, THC dominant treatments resulted in early onset to spontaneous seizures post-TBI. The alternating T-maze showed the CBD10:1 group had the highest spontaneous alternation rates whereas TBI + vehicle, CBD0, CBD1:1, and THC100:1 groups had the lowest. The novel object recognition memory task showed CBD300:1 treated animals had the best performance, while TBI or THC100:1 treated groups had the worst. The forced swim test (FST) revealed immobility time was highest after TBI and lowest after THC20:1 or THC100:1 treatment post-TBI. The elevated plus maze (EPM) revealed the CBD0 group spent the most time in closed arms. Both tests indicate that reduced anxiety was THC dependent. In the absence of TBI, THC20:1 treatment resulted in the highest mobility. All combinations resulted in reduced injury post-TBI but CBD10:1 and THC20:1 afforded the most protection and THC100:1 the least. Reduced GFAP labeling was highest with CBD dominant cannabis supporting its neuroprotective role against inflammation. Rescue of diminished bilateral PV-INs was observed within the hippocampus and medial prefrontal cortex (mPFC) with CBD dominant treatment (CBD300, CBD0) supporting their anticonvulsant effect. Loss of PV-INs with THC dominant treatment supports their proconvulsant effect. Thus, CBD and THC have different beneficial therapeutic effects indicating an optimal concentration ratio is critical for neuropathological therapeutics. SIGNIFICANCE STATEMENT: There is currently no optimal treatment that can prevent behavioral and cellular pathology as well as onset of spontaneous seizures associated with traumatic brain injury (TBI). We hypothesized that an optimal ratio of CBD:THC is required to protect against neuropathological consequences following TBI. Six extracts with varied CBD:THC ratio concentrations were compared with hemp CBD lacking THC. CBD dominant cannabis with critical THC dosing afforded the most neuroprotection and behavioral recovery, whereas THC dominant cannabis stimulated spontaneous seizure onset. CBD and THC had different beneficial therapeutic effects indicating an optimal concentration ratio is critical for neuropathological therapeutics. Absorbable medical carriers will offer delivery treatment options to optimize both short- and long-term drug efficacy relating to neuropathological disorders.