Figure 1: PQ induced cell-toxicity and protective effects of cyclo (His-Pro) in hSOD1G93A microglial cells. (A) hSOD1G93A microglial cells were treated with increasing PQ concentration and cell redox activity determined by MTT assay (6h: F3,0=36.68, P<0.001; 24h: F3,0=328.16, P<0.001 and 48h: F3,0=262.65, P<0.001, one-way ANOVA, n=3). hSOD1G93A microglial cells, pre-treated with 50μM cyclo (His-Pro) for 24h, were exposed to 25 μM PQ and used for: (B) cell redox activity assessed by MTT assay at the indicated time points. Absorbance of untreated cells (6h: 0.73 ± 0.008; 24h: 0.98 ± 0.02; 48h: 1.34 ± 0.15) was assumed as 100% (6h: F3,59=6.77, P=0.031; 24h: F3,59=17.79, P=0.003 two-way ANOVA, n=3). Data represent mean ± S.D. * vs. untreated cells, # vs. PQtreated cells; (C) viability after a 24h PQ exposure (viable cells in control sample: 2.5×104/ml assumed as 100%) (F3,59=6,9, P=0.03 two-way ANOVA, n=3). Data represent mean ± S.D. # vs. PQtreated cells; (D) morphological assessment after a 24h PQ exposure. Magnification 20X ; and (E) Apoptotic index after a 24h PQ exposure.