Fig. 1.

Procedure for preparation of F-CM and culturing cells. a Fibroblasts were rinsed with PBS when cells became confluent and refreshed with DMEM supplemented with 10% FBS. After 24 h, the media was collected and precleaned by centrifugation. b Cortical tissues isolated from neonatal SD rats were used to prepare mixed glia. DMEM/F12 with 10% FBS was changed every 3 days. On the 9th day, mixed glia were cultured with media consisting of 75% DMEM/F12 (10% FBS) and 25% F-CM, defined as the F-CM group. Comparatively, the mixed glia cultured with media consisting of 75% DMEM/F12 (10% FBS) and 25% normal DMEM (10% FBS) were defined as the NM group. Microglia were isolated via mild trypsinization on the 13th day