Cannabinoid receptor type 1 agonist ACEA improves motor recovery and protects neurons in ischemic stroke in mice.

Brain ischemia produces neuronal cell death and the recruitment of pro-inflammatory cells. In turn, the search for neuroprotection against this type of insult has rendered results involving a beneficial role of endocannabinoid receptor agonists in the Central Nervous System. In this work, to further elucidate the mechanisms associated to this neuroprotective effect, focal brain ischemia was generated by middle cerebral artery occlusion (MCAo) in C57Bl/6 mice. Three, 24 and 48 h after MCAo, animals received CB1R agonist ACEA (1 mg/kg), CB1R antagonist AM251 (1 mg/kg) or vehicle. To assess motor activity, neural deficit scores and motor tests were performed 1 day before and 3, 7, 14, 21, and 28 days after MCAo. At 7 and 28 days post lesion, cytoskeleton structure, astroglial and microglial reaction, and alterations in synapsis were studied in the cerebral cortex. ACEA treatment reduced astrocytic reaction, neuronal death, and dendritic loss. In contrast, AM251 treatment increased these parameters. Motor tests showed a progressive deterioration in motor activity in ischemic animals, which only ACEA treatment was able to counteract. Our results suggest that CB1R may be involved in neuronal survival and in the regulation of neuroprotection during focal cerebral ischemia in mice.

Effects of prenatal ethanol exposure on rat brain radial glia and neuroblast migration.

Prenatal ethanol exposure (PEE) induces morphologic and functional alterations in the developing central nervous system. The orderly migration of neuroblasts is a key process in the development of a layered structure such as the cerebral cortex (CC). From initial stages of corticogenesis, the transcription factor Pax6 is intensely expressed in neuroepithelial and radial glia cells (RGCs) and is involved in continual regulation of cell surface properties responsible for both cellular identity and radial migration. In the present work, one month before mating, during pregnancy and lactation, a group of female Wistar rats were fed a liquid diet with 5.9% (w/w) ethanol (EtOH), rendering moderate blood EtOH concentrations. Maternal gestational weight progression and fetal CC thickness were measured. CC from E12-P3 rats were examined for expression of vimentin, nestin, S-100b, Pax6 and doublecortin using immunohistochemical assays. RGCs expressing vimentin, nestin, S-100b and Pax6 had abnormal morphologies. The migration distance through the CC and the number of doublecortin-ir neuroblasts in germinative zones were decreased. We found significant morphologic defects on RGCs, a marked delay in neuronal migration, decreased numbers of neuroblasts, and decreased numbers of Pax6-ir cells in the CC as a consequence of exposure to ethanol during development. These observations suggest a sequence of toxic events that contribute to cortical dysplasia in offspring exposed to EtOH during gestation.

Prenatal ethanol exposure reduces the expression of the transcriptional factor Pax6 in the developing rat brain.

Prenatal ethanol exposure (PEE) induces functional and structural disorders in the developing central nervous system (CNS). The relationship between radial glial cells (RGCs) and migrating neuroblasts is crucial for the establishment of normal CNS laminated structures. Pax6, a transcription factor involved in mammalian neuronal developmental processes, could be affected by PEE, as it is already known to occur in amphibians. From gestational day 10 to 18 (G10-G18), pregnant Wistar rats were subjected to an intraperitoneal injection of a daily ethanol (EtOH) 3.5 g/kg dose. Control pregnant rats received equivalent volumes of saline solution. Fetal weights and cerebral cortex thickness were significantly lower in G18 PEE than in control fetuses, and neural tube defects were found in the G18 PEE fetuses. Cortical expression of vimentin (an RGC cytoskeletal marker), S-100b protein (a neurotrophic factor and cytosolic marker of RGCs during embryonic development), and 68 kDa neurofilaments (a neuronal cytoskeletal marker) were also decreased in G18 PEE fetuses. At G14, a reduction in Pax6 cortical expression was found. Our results suggest that PEE reduces Pax6 expression in undifferentiated mammalian CNS cells. This could be one of the factors that induce RGCs and neuronal alterations at end-gestation. These alterations could be involved in the pathophysiology of neurodevelopmental disorders observed in the children affected by the fetal alcohol syndrome.