Adult rat hippocampus soluble factors: a novel transplantation model mimicking intracranial microenvironment for tracing the induction and differentiation of adipose-derived stromal cells in vitro.

Intracranial transplantation of ADSCs induces recovery of CNS diseases, but how they develop in host is poorly understood. The aim of this study is to observe induction and differentiation of ADSCs in the presence of hippocampus soluble factors (HiSF) extracted from the hippocampus of adult Wistar rats to mimic an intracranial microenvironment. To determine the optimal microenvironment, five conditions were tested: 0μg/ml (as control), 50μg/ml, 100μg/ml, 200μg/ml, and 400μg/ml of HiSF. The number of neurospheres was significantly higher in 200μg/ml group than in other groups on the sixth day. Immunofluorescence demonstrated that the neurospheres induced from ADSCs in 200μg/ml group expressed both nestin and CD133, which are more highly expressed in neurospheres than in ADSCs. This result was confirmed by Western blot analysis. Quantitative PCR revealed that the mRNA levels of nestin and CD133 in the neurospheres were 145- and 220-fold higher, respectively, than those in ADSCs. In the presence of 200μg/ml HiSF and 1% FBS, the neurospheres can further differentiate into Schwann-like cells which expressing characteristic markers GFAP, S100 and P75 NGFR. These data indicated that HiSF, mimicking a destination of ADSCs transplanted model in vitro, could effectively induce and differentiate neurospheres, representing a new method to obtain NSCs and Schwann-like cells from ADSCs.