Investigação dos efeitos do canabidiol e seus análogos na epilepsia: abordagens in vitro e in vivo

Abstract

Epilepsy is a neurological disorder characterized by the periodic occurrence of unpredictable seizures, caused by the hyperexcitability of brain neurons. The adverse effects of traditional antiepileptic drugs, as well as their ineffectiveness in refractory cases, have led to the exploration of alternative treatments for epilepsy, such as the use of Cannabidiol (CBD), the main non-psychoactive compound found in the Cannabis spp. plant. It is believed that some of its analogs may be equally effective in mitigating epileptic symptoms, necessitating further research in the field to improve epilepsy treatment. To elucidate the effects of CBD and its analogs on epilepsy, we employed various experimental approaches and models both in vitro and in vivo. For in vitro tests, we analyzed cell viability, glutamate quantification (intracellular and extracellular) by HPLC, neuronal electrical activity, and the expression of glial fibrillary acidic protein (GFAP). For in vivo studies, we used the pentylene tetrazole (PTZ) epilepsy induction model in 11-day-old Wistar rats, assessing seizure latency and duration, and in 7-day-old Zebrafish larvae, evaluating distance, speed, immobility time, and rotation, as well as the expression of c-Fos and interleukin-1beta. Experimental groups were compared using One-way ANOVA (Tukey's post-test). In the in vitro study with 1mM glutamate addition, we found that in the cell viability test, CBD and compounds 245 and 309 (10µM) were able to reverse the loss of viability induced by glutamate. When quantifying glutamate by HPLC, compounds 291 and 309 increased intracellular glutamate uptake. Analysis of neuronal electrical activity showed that glutamate significantly increased the average percentage of spikes/15 minutes, while pre-treatment for 3 hours and 24 hours with CBD and analogs 302 and 309 normalized the spikes. CBD and analog 302 showed a significant reduction in GFAP expression. For in vivo tests, the Wistar rat model showed no difference between treatments. However, in the Zebrafish model, CBD and its analogs demonstrated a reduction in the studied parameters compared to the PTZ group. Neuronal activity assessed by c-Fos quantification showed a significant reduction with CBD and analogs 302 and 309 compared to the PTZ group. These findings suggest that CBD analogs are promising as potential treatments for epilepsy.