Caracterização da modulação da resposta glial pelo flavonoide agatisflavona em modelo in vitro de trauma crânio encefálico

Abstract

Traumatic Brain Injury (TBI) is a complex and multifactorial pathology, being a major cause of death and disability for humans. Immediately after TBI, astrocytes and microglia react with complex morphological and functional changes known as reactive gliosis and forms, in the area immediately adjacent to the lesion, the glial scar, the major barrier to neuronal regeneration in the central nervous system. The flavonoid agathisflavone (bis-apigenin), present in Poincianella pyramidalis leaves, has been shown to have neurogenic, neuroprotective, and anti-inflammatory effects, demonstrated in vitro models of glutamate-induced toxicity, neuroinflammation, and demyelination. The present study investigated, the effect of agathisflavone in neuronal integrity and in the modulation of gliosis in ex vivo models of TBI. Methodology: Microdissections from the encephalon of Wistar rats (P6-8), were prepared and subjected to mechanical injury (MI) and treated or not daily with agathisflavone (5 μM) for 3 days. Astrocyte reactivity was investigated by measuring mRNA and expression of GFAP protein in the lesioned area by immunofluorecence and westernblot; proportion of microglia was determined by immunofluorescence for Iba-1; mRNA expression for inflammasome NRPL3 and interleukin -1 beta (IL-1β) was determined by RT-qPCR. Results: It was observed that lesion of the cortical tissue induced astrocytes over expressing GFAP in the typical glial scar formed, and agathisflavone modulated GFAP expression at transcriptional and pos-transcriptional level associated with reduction of glial scar. MI induced increase in the proportion of microglia (Iba-1+) that was not observed in agathisflavone treated cultures. Moreover, the flavonoid modulated negatively both NRLP3 and IL-1β mRNA expression that was increases in the lesioned area of the tissue. Conclusion: All of these findings reiterate the regulatory property of the inflammatory response of glial cells by the flavonoid agathisflavone, which can impact in neuroprotection and should be considered for future pre-clinical and clinical studies for CNS pathologies, including TBI.