Ação neuroprotetora da ayahuasca no córtex pré-frontal de saguis (Callithrix jacchus) induzidos a um estado depressivo

Abstract

Major depressive disorder can present as a single or recurrent episode, lasting days, with different symptoms influencing everyday relationships. One of the main causes of this disorder is chronic stress, and the biological response to these stressors can cause dysregulation in human physiology. Our group aims to identify the neuroprotective competence of Ayahuasca in behavioral and morphoquantitative aspects in the prefrontal cortex of marmosets (Callithrix jacchus) subjected to an induced chronic stress protocol. 4 males and 4 females were used, allocated into 3 groups, 02 in the family group (GF), 02 in the isolated group (GI) and 04 in the treated group (GT), all selected randomly. We selected specimens aged between 7 and 9 months of age. The behavioral record was collected using the continuous focal sampling method, collecting frequency and/or duration of behaviors. A fraction (1/6) of the sections obtained from the brain microtomy were subjected to histological staining using Nissl techniques. To estimate the morphoquantitative parameters, stereology, a three-dimensional histological quantification technique, was used. Among the behaviors, we did not find significant differences between the groups in the experimental phase, except in food intake (H(2) = 6.00, p = 0.050). Regarding the total volume of the prefrontal cortex (PFC), no significant difference was found between groups (H(2) = 3.00, p = 0.223). With regard to neuronal density, it visually appeared to be more intense in GF and GT compared to GI in the three selected areas of the prefrontal cortex. Regarding the mean neuronal volume of the medial prefrontal cortex (VN-mCPF), we found a significant difference between groups (H(2) = 5.37, p = 0.057); in the mean neuronal volume of the dorsolateral prefrontal cortex (VNdlCPF), we found no significant difference between groups (H(2) = 3.81, p = 0.098); in the mean neuronal volume of the ventral prefrontal cortex (VN-vCPF), a significant difference was found between groups (H(2) = 7.75, p = 0.029). In this study, we observed a subtle reduction in the volume of the marmoset's prefrontal cortex when comparing the GF with the GI, which can be corroborated by some behaviors, dependent on social command, which also showed a reduction. In the mCPF and dlCPF we observed an average reduction of 25% in neuronal density when comparing the GF with the GI. When comparing GF with GT we observed similarity in quantities. The atrophy of neurons in the prefrontal cortex is associated with depressive and anxiety disorders. This characteristic was identified in marmosets from the GI region of the three regions of the PFC (medial, dorsolateral and ventral), suggesting that it is a marker of the depressive state. We assessed that in GT the neuronal volume is similar to GF, data found in the three regions of the PFC. These results indicate that Ayahuasca has a neuroprotective action in maintaining the number of neurons and neuronal volume, preventing the atrophy characteristic in the context of depression. Finally, prophylactic Ayahuasca treatment can help protect the prefrontal cortex and this is a benefit for the world population that is increasingly suffering from this disease.