Neuroregenerative “Bystander”-Effects of Conditioned Media from Adipose Tissue-Derived Fibroblast-Like Cells in Vitro

A promising direction in the development of new technologies for the treatment of the central nervous system diseases is the use of different types of stem cells, in particular, mesenchymal multipotent stromal cells (MMSCs) and neurogenic stem/progenitor cells (NSCs/NPCs). An alternative to direct cell transplantation may be the use of their conditioned media (CM) as a source of secretome and a key component of the mechanism of realization of their potential. Currently, in clinical trials using cell therapy in CNS pathology, the adipose tissue, bone marrow, umbilical cord and cord blood are most commonly used as a source for isolation of the MMSCs or mononuclear cells of the stromal-vascular fraction, and as a source of the NSCs/NPCs the lines of immortalized neurogenic cells isolated from structures of the brain or spinal cord of the human embryo are used. In experimental conditions, in particular in rodents, one of the most available sources of allogenic progenitor cells of the mesenchymal type is adipose tissue, and fetal brain is accessible source of neurogenic cells. The aim was to study the neuroregenerative effects of conditioned media from rat adipose tissue-derived fibroblast-like cells and fetal neurogenic cells in vitro. Methods. CM from 24 h cultures of rat adipose tissue-derived fibroblast-like cells (ad-FLCs) and fetal neurogenic cells (NCs, E14) were examined by electrophoresis in 10% polyacrylamide gel. On 5–7 day in 2D cultures of rat neural cells (E14) the “scratch assay” was performed and nutrient medium DMEM with 10% fetal calf serum (standard culture conditions, control) or 0.10 mg/mL (by amount of protein) ad-FLCs CM or NCs CM were added. Microscopic and morphometric studies were performed during 4-day cultivation. Results. After mechanical transection in the culture of neural cells under standard conditions from the 1 to the 3 day there were processes of endogenous regeneration, which decreased to the 4 day. The addition of ad-FLCs CM or NCs CM contributed to a significant increase in the degree and duration of endogenous regeneration processes in neural cell culture. Exposure to ad-FLCs CM increased to the 4 day in the scratch area the number of migrated cells (7 times) and the density of cell processes (12.5 times); exposure to NCs CM increased the number of migrated cells (3.5 times), the distance of cell migration (1.4 times), the density of cell processes (13 times). The length of the overgrown section of the scratch area increased after exposure to ad-FLCs CM in 1.7 times, NCs CM—3 times, reaching respectively 23.7 and 43.5% of the total length of the transection zone. 10 protein fractions were detected in the ad-FLCs CM: predominant 12, 15, 23, 30, 80 kDa and minor—28, 35, 55, 65, 75 kDa; in NCs CM—9 fractions: prevailing 15, 23, 30, 35 kDa and minor—37, 40, 46, 67, 80 kDa. Conclusions. CM from 24 h cultures of rat ad-FLCs or NCs (E14) stimulate endogenous regeneration processes in rat brain cell culture with mechanical monolayer transection. The affecting factors of neuroregenerative “bystander” effects of rat ad-FLCs or NCs are secreted biologically active proteins—components of the CM predominant and minor protein fractions.