The endocannabinoid system (eCS) is widely distributed in mammalian tissues and it is classically formed by cannabinoid receptors, endogenous bioactive lipids and its synthesis and degradation enzymes. Due to the modulatory role of eCS in synaptic activity in the Central Nervous System (CNS), phytocannabinoids have been increasingly used for the treatment of neurological disorders, even though little is known in terms of the long-term effect of these treatments on CNS development, mainly in the timeframe that comprises childhood and adolescence. Furthermore, an increased number of clinical trials using full-spectrum Cannabis extracts has been seen, rather than the isolated form of phytocannabinoids, when exploring the therapeutical benefits of the Cannabis plant. Thus, this study aims to evaluate the effect of cannabidiol (CBD)-enriched Cannabis extract on synaptic components in the hippocampus of rats from adolescence to early adulthood (postnatal day 45 to 60). Oral treatment of healthy male Wistar rats with a CBD-enriched Cannabis extract (3 mg/kg/day CBD) during 15 days did not affect food intake and water balance. There was also no negative impact on locomotor behaviour and cognitive performance. However, the hippocampal protein levels of GluA1 and GFAP were reduced in animals treated with the extract, whilst PSD95 levels were increased, which suggests rearrangement of glutamatergic synapses and modulation of astrocytic features. Microglial complexity was reduced in CA1 and CA3 regions, but no alterations in their phagocytic activity have been identified by Iba-1 and LAMP2 co-localization. Collectively, our data suggest that CBD-enriched Cannabis treatment may be safe and well-tolerated in healthy subjects, besides acting as a neuroprotective agent against hippocampal alterations related to the pathogenesis of excitatory and astrogliosis-mediated disorders in CNS.

Oral administration of drugs in laboratory rodents such as rats is conventionally performed using the gavage technique. Despite effectiveness, gavage can induce distress associated with restraint, especially following repeated animal handling. To mitigate these adverse effects and reduce morbidity associated with traditional methods, we explored oromucosal/buccal administration of cannabidiol (CBD)-enriched Cannabis extract. In this method, male rats were treated daily for 15 days with medium-chain triglycerides (TCM) derived from coconut oil or CBD-enriched Cannabis extract. Each treatment was administered individually while animals were gently immobilized using an affectionate touch technique. The administration involved the use of a micropipette to apply the oily formulation directly into the oral mucosa. The dosage was calculated based on the CBD concentration in the Cannabis extract, standardized at 3 mg/kg/day. To ensure accuracy, animals were weighed daily, allowing for dose adjustments in accordance with weight changes over the treatment period. This method offers non-invasive and stress-reducing treatment, potentially improving animal welfare in experimental settings. The treatment with CBD-enriched Cannabis extract was safe, and the analysis of the hippocampus of these animals' showed alterations in the expression levels of GluA1 and GFAP proteins, which are directly associated with glutamatergic receptor functionality and neuroinflammation, respectively. This suggests that Cannabis extract could be applied in pathological conditions where glutamatergic excitotoxicity and astrogliosis are observed.

Oral administration of drugs in laboratory rodents such as rats is conventionally performed using the gavage technique. Despite effectiveness, gavage can induce distress associated with restraint, especially following repeated animal handling. To mitigate these adverse effects and reduce morbidity associated with traditional methods, we explored oromucosal/buccal administration of cannabidiol (CBD)-enriched Cannabis extract. In this method, male rats were treated daily for 15 days with medium-chain triglycerides (TCM) derived from coconut oil or CBD-enriched Cannabis extract. Each treatment was administered individually while animals were gently immobilized using an affectionate touch technique. The administration involved the use of a micropipette to apply the oily formulation directly into the oral mucosa. The dosage was calculated based on the CBD concentration in the Cannabis extract, standardized at 3 mg/kg/day. To ensure accuracy, animals were weighed daily, allowing for dose adjustments in accordance with weight changes over the treatment period. This method offers non-invasive and stress-reducing treatment, potentially improving animal welfare in experimental settings. The treatment with CBD-enriched Cannabis extract was safe, and the analysis of the hippocampus of these animals' showed alterations in the expression levels of GluA1 and GFAP proteins, which are directly associated with glutamatergic receptor functionality and neuroinflammation, respectively. This suggests that Cannabis extract could be applied in pathological conditions where glutamatergic excitotoxicity and astrogliosis are observed.