Cannabidiol reduces brain damage and improves functional recovery in a neonatal rat model of arterial ischemic stroke

- Post-stroke administration of Cannabidiol (CBD) is neuroprotective in neonatal rats.
- CBD neuroprotection is sustained in the long term.
- CBD treatment led to functional recovery in both motor and sensorimotor domains.
- CBD modulated excitotoxicity, astrocyte dysfunction and microglial activation.

Backgroundand purpose: Currently there is no effective treatment for neonatal arterial ischemic stroke (AIS). Cannabidiol (CBD) is neuroprotective in models of newborn hypoxic-ischemic brain damage and adult stroke. The purpose of this work was to study the protective effect of CBD in a neonatal rat model of AIS.MethodsMiddle Cerebral Artery Occlusion (MCAO) was achieved in neonatal Wistar rats by introducing a nylon filament to the left MCA for 3 h; 15 min after removing the occluder vehicle (MCAO-V) or CBD single dose 5 mg/kg (MCAO-C) were administered i. p. Similarly manipulated but non-occluded rats served as controls (SHM). A set of behavioral tests was then conducted one week (P15) or one month (P38) after MCAO. Brain damage was then assessed by magnetic resonance imaging (MRI), proton magnetic resonance spectroscopy (H+-MRS) and histologic (TUNEL for cell death, immunohistochemistry for neuron, astrocyte and microglia identification) studies.ResultsCBD administration improved neurobehavioral function regarding strength, hemiparesis, coordination and sensorimotor performance as assessed at P15 and P38. MRI indicated that CBD did not reduce the volume of infarct but reduced the volume of perilesional gliosis. H+-MRS indicated that CBD reduced metabolic derangement and excitotoxicty, and protected astrocyte function. Histologic studies indicated that CBD reduced neuronal loss and apoptosis, and modulated astrogliosis and microglial proliferation and activation.ConclusionsCBD administration after MCAO led to long-term functional recovery, reducing neuronal loss and astrogliosis, and modulating apoptosis, metabolic derangement, excitotoxicity and neuro-inflammation.