Curcumin reduces microglial neurotoxicity on photoreceptors. (A) Phase contrast micrographs showing morphological changes of 661W photoreceptor cell cultures treated with conditioned media from BV-2 cells for 48 hours. The supernatant from control-stimulated, 20 μM curcumin-treated, 100 ng/ml LPS-treated, or 20 μM curcumin + 100 ng/ml LPS-treated cells was added to 661W photoreceptor cells, respectively. The micrographs shown are from one representative experiment out of three independent experiments with the same tendencies. (B) Apoptosis-related caspase 3/7 activation in 661W photoreceptor cells incubated with conditioned media from control-stimulated, 20 μM curcumin-treated, 100 ng/ml LPS-treated, or 20 μM curcumin + 100 ng/ml LPS-treated BV-2 cells. Results are calculated from three independent experiments performed in duplicate measurements. * p ≤ 0.05 for LPS vs. control and # p ≤ 0.05 for curcumin + LPS vs. LPS, respectively, Mann-Whitney Rank Sum test. RLU, relative luciferase units.