pilepsy affects approximately 1% of the overall population worldwide. Currently, 25%-30% of patients suffering from epilepsy are pharmacoresistant to all types of anti-seizure medication. For this reason, in the last decades’ alternative medicine has received more attention in the search for novel therapeutics. Recently, compounds found in Cannabis sativa L. have received great interest in the treatment of drug-resistant epilepsy. Cannabidiol (CBD) is successfully used as an add-on medication for infantile epilepsy including Lennox-Gastaut and Dravet syndrome, and is thought to be a safe compound with few side effects. In addition, CBD-rich Cannabis extracts seem to present a beneficial effect on epileptic seizures. In detail, C. sativa extracts display a promising anti-seizure profile due to the synergistic effects of terpenes and other phytocannabinoids. In literature, an interaction was described between CBD and peroxisome proliferator-activated receptor gamma (PPARγ). The role of PPARγ has been well documented in metabolic disorders but has lately been studied in its involvement in neurological diseases. The neuroprotective activity of CBD in ischemic stroke and neurological disorders, including epilepsy, is hypothesized to be mediated by PPARγ. In my thesis, I aimed to: 1) determine the anticonvulsant activity of C. sativa extracts in the repeated 6-Hz corneal stimulation model in mice and 2) evaluate the anti-seizure effects of CBD in the kainic acid model of temporal lobe epilepsy in rats, and if CBC effects were associated with PPARγ regulation. Additionally, I investigated the presence of regional specific effects in the hippocampal formation. Particularly, I first tested two hemp oils with different concentrations of terpenes in the modified repeated 6-Hz corneal stimulation model, which were administered by gavage 1h before the stimulation. In the second approach, the role of CBD was assessed in epileptic rats previously treated with kainic acid. Sixty-seven days after the induction of status epilepticus and the appearance of spontaneous recurrent seizures in all rats, CBD was administered subcutaneously twice a day for three days. In both approaches, the animals were evaluated by video-electrocorticographic recordings, behavioral analysis based on a modified Racine scale, and immunohistochemical staining. Both C. sativa extracts significantly diminished the percentage of mice experiencing convulsive seizures in comparison to olive oil-treated mice, but only the oil enriched with a high concentration of terpenes significantly accelerated full recovery from the seizure. These effects occurred in the presence of reduced power of delta rhythm, and, instead, increased power of theta rhythm, along with a lower FosB/∆FosB expression detected in the subiculum. Further, CBD abolished the seizures in 50% of rats and reduced total seizure duration and occurrence. After the administration of CBD at 12 and 120 mg/kg, PPARγ levels increased in the hippocampal CA1 subfield and subiculum. However, only the highest dose also increased the immunoreactivity in the hippocampal CA3 subfield, perirhinal cortex, and amygdala. Overall, these findings suggest that both cannabinoids and terpenes in oil extracts should be considered as potential therapeutic agents against epileptic seizures and epilepsy and that the antiseizure effects of CBD are characterized by a regional specificity and, finally, are associated with an upregulation of PPARγ in the hippocampal CA3 region.

Il 25-30% dei pazienti affetti da epilessia è farmacoresistente a qualsiasi classe di farmaci antiepilettici. Recentemente, i composti presenti nella Cannabis sativa L. hanno riscosso un grande interesse nel trattamento dell'epilessia farmacoresistente. Il cannabidiolo (CBD) è usato come farmaco aggiuntivo per il trattamento di pazienti in età pediatrica, in quanto si pensa che sia un composto sicuro con pochi effetti collaterali. Inoltre, gli estratti di Cannabis ricchi di CBD sembrano avere un effetto benefico sulle convulsioni epilettiche. Infatti, si ipotizza che gli estratti di Cannabis presentino possibili proprietà anticonvulsivanti grazie all’effetto sinergico dei terpeni e di altri fitocannabinoidi. E’ stata descritta una interazione tra CBD e il recettore gamma attivato dai proliferatori dei perossisomi (PPARγ). Il coinvolgimento di PPARγ nelle malattie neurologiche è stato recentemente publicato. L'attività neuroprotettiva del CBD nell'ictus ischemico e nei disturbi neurologici, tra cui l'epilessia, si suggerisce essere mediata da PPARγ. Nella mia tesi di dottorato di ricerca, l’obiettivo è quello di: 1) determinare una possibile attività anticonvulsivante degli estratti di C. sativa in un modello in cui le crisi epilettiche sono indotte da ripetute stimolazioni elettriche corneali alla frequenza di 6 Hz nei topi e 2) valutare gli effetti antiepilettici del CBD in ratti affetti da epilessia del lobo temporale, precedentemente esposti ad acido cainico, e se gli effetti di CBD siano associati alla regolazione di PPARγ. Inoltre, ho studiato la presenza di effetti regionali specifici nella formazione dell'ippocampo. In particolare, ho testato due oli di canapa con diverse concentrazioni di terpeni nel modello in cui le crisi epilettiche sono indotte da ripetute stimolazioni elettriche corneali alla frequenza di 6 Hz, somministrandoli mediante sonda gastrica 1 ora prima della stimolazione. Nel secondo approccio, è stato valutato il ruolo del CBD nei ratti epilettici precedentemente trattati con acido cainico. Sessantasette giorni dopo l'induzione dello stato di male epilettico e la comparsa di convulsioni spontanee e ricorrenti in tutti i ratti, il CBD è stato somministrato per via sottocutanea due volte al giorno per tre giorni. In entrambi gli approcci, gli animali sono stati valutati mediante registrazioni ECoG, analisi comportamentali basate sull’utilizzo di una scala di Racine modificata, e analisi immunoistochimiche. Entrambi gli estratti hanno ridotto significativamente la percentuale di topi che hanno avuto crisi di tipo convulsivo rispetto ai topi trattati con il solo olio d'oliva, ma solo l'olio arricchito con un'alta concentrazione di terpeni ha accelerato significativamente il pieno recupero delle normali attività dopo la crisi epilettica. Questi effetti si sono verificati in presenza di una riduzione delle onde cerebrali di tipo delta e, al contrario, un aumento delle onde di tipo theta, insieme a una ridotta espressione di FosB/∆FosB nel subiculum. Inoltre, il CBD ha abolito lo sviluppo delle convulsioni epilettiche nel 50% dei ratti e ha ridotto la durata e il numero totale delle crisi di tipo convulsivo. Dopo la somministrazione di 12 e 120 mg/kg di CBD, i livelli di PPARγ risultano essere aumentati nella regione CA1 dell'ippocampo e nel subiculum. Oltre a ciò, la dose più elevata di CBD si è dimostrata efficace nell’indurre un aumento dei livelli di PPARγ nella regione CA3 dell'ippocampo, nella corteccia peririnale e nell'amigdala. In conclusione, questi risultati suggeriscono che sia i cannabinoidi che i terpeni negli estratti di olio di canapa dovrebbero essere considerati come potenziali agenti terapeutici contro le crisi epilettiche e l'epilessia. Infine, si suggerisce che gli effetti antiepilettici del CBD sono caratterizzati da una specificità regionale e, infine, possano essere associati ad un aumento dei livelli di PPARγ nella regione CA3 dell'ippocampo.

EFFETTI ANTICONVULSIVANTI DEI COMPOSTI PRESENTI IN CANNABIS SATIVA L. IN MODELLI SPERIMENTALI CON RODITORI: REGIONI IPPOCAMPALI COINVOLTE E POSSIBILI MEDIATORI / Lara Senn , 2023 May 19. 35. ciclo, Anno Accademico 2021/2022.

EFFETTI ANTICONVULSIVANTI DEI COMPOSTI PRESENTI IN CANNABIS SATIVA L. IN MODELLI SPERIMENTALI CON RODITORI: REGIONI IPPOCAMPALI COINVOLTE E POSSIBILI MEDIATORI

SENN, LARA
2023

Abstract

pilepsy affects approximately 1% of the overall population worldwide. Currently, 25%-30% of patients suffering from epilepsy are pharmacoresistant to all types of anti-seizure medication. For this reason, in the last decades’ alternative medicine has received more attention in the search for novel therapeutics. Recently, compounds found in Cannabis sativa L. have received great interest in the treatment of drug-resistant epilepsy. Cannabidiol (CBD) is successfully used as an add-on medication for infantile epilepsy including Lennox-Gastaut and Dravet syndrome, and is thought to be a safe compound with few side effects. In addition, CBD-rich Cannabis extracts seem to present a beneficial effect on epileptic seizures. In detail, C. sativa extracts display a promising anti-seizure profile due to the synergistic effects of terpenes and other phytocannabinoids. In literature, an interaction was described between CBD and peroxisome proliferator-activated receptor gamma (PPARγ). The role of PPARγ has been well documented in metabolic disorders but has lately been studied in its involvement in neurological diseases. The neuroprotective activity of CBD in ischemic stroke and neurological disorders, including epilepsy, is hypothesized to be mediated by PPARγ. In my thesis, I aimed to: 1) determine the anticonvulsant activity of C. sativa extracts in the repeated 6-Hz corneal stimulation model in mice and 2) evaluate the anti-seizure effects of CBD in the kainic acid model of temporal lobe epilepsy in rats, and if CBC effects were associated with PPARγ regulation. Additionally, I investigated the presence of regional specific effects in the hippocampal formation. Particularly, I first tested two hemp oils with different concentrations of terpenes in the modified repeated 6-Hz corneal stimulation model, which were administered by gavage 1h before the stimulation. In the second approach, the role of CBD was assessed in epileptic rats previously treated with kainic acid. Sixty-seven days after the induction of status epilepticus and the appearance of spontaneous recurrent seizures in all rats, CBD was administered subcutaneously twice a day for three days. In both approaches, the animals were evaluated by video-electrocorticographic recordings, behavioral analysis based on a modified Racine scale, and immunohistochemical staining. Both C. sativa extracts significantly diminished the percentage of mice experiencing convulsive seizures in comparison to olive oil-treated mice, but only the oil enriched with a high concentration of terpenes significantly accelerated full recovery from the seizure. These effects occurred in the presence of reduced power of delta rhythm, and, instead, increased power of theta rhythm, along with a lower FosB/∆FosB expression detected in the subiculum. Further, CBD abolished the seizures in 50% of rats and reduced total seizure duration and occurrence. After the administration of CBD at 12 and 120 mg/kg, PPARγ levels increased in the hippocampal CA1 subfield and subiculum. However, only the highest dose also increased the immunoreactivity in the hippocampal CA3 subfield, perirhinal cortex, and amygdala. Overall, these findings suggest that both cannabinoids and terpenes in oil extracts should be considered as potential therapeutic agents against epileptic seizures and epilepsy and that the antiseizure effects of CBD are characterized by a regional specificity and, finally, are associated with an upregulation of PPARγ in the hippocampal CA3 region.
ANTISEIZURE EFFECTS OF CANNABIS SATIVA L. DERIVATIVES IN RODENT MODELS: TARGETED HIPPOCAMPAL REGIONS AND HYPOTHESIZED MEDIATORS
19-mag-2023
BIAGINI, Giuseppe
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1305587
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