Dynamics of morphological changes in neural cell culture with a model of neurotrauma under the influence of conditioned media of the rat fetal brain neurogenic cells

Abstract

A potential strategy for recovery and regeneration of brain damage due to traumatic brain injury is considered to be the transplantation of neurogenic stem and/or progenitor cells (NSCs/NPCs). The key factors of the regenerative non-targeted effects of NSCs/NPCs (so-called bystander effects) include the signal molecules produced by them into the extracellular environment (secretome). The purpose is to study the regenerative bystander effects of rat fetal brain neurogenic cells (FBNCs) in the in vitro model of neurotrauma. Materials and methods. In cell culture of FBNCs from rat fetuses (E14-16), neurotrauma was modeled in vitro by mechanical scratching of monolayer and conditioned medium obtained from 24-h cultures of rat FBNCs was added. Cell phenotype was evaluated by morphological features and by immunocytochemical staining for Nestin and GFAP. The density and length of processes, migration capacity, the cell growth rate and monolayer density in the scratched area were compared. Morphometric study included analysis of the width of the scratched area, the number of migrating cells, the distance of migration and mitotic activity in the intact monolayer. Results. Under the conditions of the nutrient medium of standard composition in the scratched area the signs of endogenous regeneration are shown during 24-48 h of cultivation. The overgrowth of cell processes from monolayer and short distance migration of single undifferentiated or poorly differentiated cells were shown. In the next 72-96 h of observation, the degeneration of migrated cells and processes in the scratched area was detected. Under the influence of conditioned media from 24-h cultures of FBNCs by single addition immediately after scratching at dose of 0.1 mg/ml for protein content the stimulation of regeneration were detected up to 96 hours of cultivation. The migration of cell processes from the monolayer simultaneously with undifferentiated or poorly differentiated cells at 24 hours was shown. The formation of cell clusters and their differentiation (at 48 h), as well as migration of differentiated cells with partial or complete overgrowth of scratched area (72-96 h) were observed. The morphological signs of degeneration of migrated cells in the scratched area appeared only on the 8th day of cultivation. Conditioned media does not affect qualitative and quantitative properties of the culture of rat FBNCs in the intact area where mitotic activity was average. Conclusions. Conditioned medium from 24-h cultures of rat FBNC can stimulate reparation in the in vitro model of neurotrauma in neural cell culture for at least 7 days at a single addition, without affecting the cellular composition and mitotic activity of the intact monolayer.