Figure 8.

Neuronal viability in the presence of microglia conditioned medium. Neuronal viability was assessed by the Alamar Blue Assay after exposure to conditioned medium obtained from N9 cells. N9 cells were transfected with anti-microRNA-155 (miR-155) oligonucleotides (anti-miR155 oligo) or non-targeting oligonucleotides (control oligo) for 4 hr. Twenty-four hours after transfection, cells were incubated with lipopolysaccharide (LPS) at 0.1 μg/ml for 18 hr and the N9 conditioned medium (CM) was collected. CM was also collected from untransfected and untreated N9 cells (control CM), or from untransfected LPS-treated cells (LPS 0.1 μg/ml CM). Primary cortical neurons were obtained at day 16 of gestation and cultured in Neurobasal medium (NBM) for 10 days before incubation with a mixture of CM and NBM at a ratio of 1 : 1 (v/v) for 24 hr. Alternatively, neuronal cultures were incubated directly with LPS at 0.1 μg/ml for the same period of time. Results are presented as a % of neuronal viability with respect to control cells. **P < 0.01 compared with neurons incubated with LPS 0.1 μg/ml CM. Results are representative of three independent experiments performed in triplicate.