Ar-turmerone increases NSC proliferation in vitro. (A) Ar-turmerone significantly increased the numbers of fetal rat NSCs in primary monolayer culture (mean ± SEM; *P < 0.05, compared with control), dependent on its concentration; representative phase-contrast images are depicted of NSC-treated without (Aʹ) or with (Aʹʹ) 6.25 μg/ml ar-turmerone (bar represents 200 μm). (B) Ar-turmerone significantly increased the number of proliferating NSCs, as assessed by BrdU-incorporation (mean ± SEM; **P < 0.01, compared with control), dependent on its concentration; representative images are depicted of NSCs treated without (Bʹ) or with (Bʹʹ) 3.125 μg/ml ar-turmerone, stained for BrdU-incorporation (bar represents 200 μm). (C) Treating NSCs with 6.25 μg/ml ar-turmerone led to a significant increase in Ki67 mRNA; mRNA levels were normalized to endogenous RPL13a expression and calculated with the 2-ΔCt method; data are depicted as mean ± SEM; *P < 0.05. (D) In high concentrations, ar-turmerone significantly decreased ratio of surviving NSCs within 24 hours of treatment, wheres concentrations between 1.56 and 6.25 μg/ml had no effect (mean ± SEM; *P < 0.05, compared with control).