Agathisflavone modulates astrocytic responses and increases the population of neurons in an in vitro model of traumatic brain injury.

Traumatic brain injury (TBI) is a critical health problem worldwide, with a high incidence rate and potentially severe long-term consequences. Depending on the level of mechanical stress, astrocytes react with complex morphological and functional changes known as reactive astrogliosis. In cases of severe tissue injury, astrocytes proliferate in the area immediately adjacent to the lesion to form the glial scar, which is a major barrier to neuronal regeneration in the central nervous system. The flavonoid agathisflavone has been shown to have neuroprotective, neurogenic, and immunomodulatory effects and could have beneficial effects in situations of TBI. In this study, we investigated the effects of agathisflavone on modulating the responses of astrocytes and neurons to injury, using the in vitro scratch wound model of TBI in primary cultures of rat cerebral cortex. In control conditions, the scratch wound induced an astroglial injury response, characterized by upregulation of glial fibrillary acidic protein (GFAP) and hypertrophy, together with the reduction in proportion of neurons within the lesion site. Treatment with agathisflavone (1 µM) decreased astroglial GFAP expression and hypertrophy and induced an increase in the number of neurons and neurite outgrowth into the lesion site. Agathisflavone also induced increased expression of the neurotrophic factors NGF and GDNF, which are associated with the neuroprotective profile of glial cells. These results demonstrate that in an in vitro model of TBI, the flavonoid agathisflavone modulates the astrocytic injury response and glial scar formation, stimulating neural recomposition.

Lupeol inhibits LPS-induced neuroinflammation in cerebellar cultures and induces neuroprotection associated to the modulation of astrocyte response and expression of neurotrophic and inflammatory factors.

In the central nervous system (CNS), neuroinflammation, especially that modulated by the cell response of astrocytes and microglia, is associated with damage to neurons in neurodegenerative disorders such as Parkinson's disease, Alzheimer's disease and, Multiple Sclerosis. Lupeol is a dietary triterpene that has demonstrated biological activities as antioxidant. This study investigated the anti-inflammatory and neuroprotective effects of lupeol in an in vitro model of neuroinflammation in primary cerebellar cultures. Cultures were obtained from 6-day-old Wistar rats, subjected to inflammatory damage with lipopolysaccharide (LPS, 1 µg/mL) and treated with lupeol (0.1 µM). We observed, after a 48-hour treatment, through Fluorjade-B staining and immunocytochemistry (ICQ) for ßIII-tubulin, that lupeol induced neuroprotection in cultures submitted to inflammatory damage. On the other hand, through ICQ for GFAP, it was possible to observe that lupeol modulated the astrocyte morphology for Bergmann glia-like phenotype and, especially for velate astrocyte-like phenotype, both phenotypes associated with the neuroprotective profile. Moreover, RT-qPCR analysis showed that lupeol induced the down-regulation of the mRNA expression for proinflammatory markers TNF, iNOS and NLRP3, as well as the production of nitric oxide (method of Greiss), which were up-regulated by LPS, and also induced up-regulation of the mRNA expression for arginase and IL-6 mRNA. In addition, lupeol induced up-regulation of mRNA expression for neurotrophins GDNF and NGF and also for the sonic hedgehog-Gli pathway. Together, these results lead to the conclusion that lupeol inhibits neuroinflammation in cerebellar cultures and induces neuroprotection associated with the modulation of astrocyte response and expression of neurotrophic and inflammatory factors.