Fig. 2

Minocycline stimulation dampens microglial NO production and reduces their neurotoxic potential on 661W photoreceptors. BV-2 cells were pre-treated with 50 μg/ml minocycline or NaCl for 30 min. The cells were then further stimulated with either 50 μg/ml minocycline, 50 ng/ml LPS, or a combination of both. a Twenty-four hours later, the nitric oxide production was determined by Griess reaction which detects the amount of nitrite in the cell culture supernatant. Data show mean ± SEM (n = 3/group, measured in triplicates). b To determine the neurotoxic potential of microglia, the cell culture supernatant of the differentially treated microglial cells was transferred to 661W photoreceptor cells. Furthermore, cell culture supernatant of untreated and LPS-stimulated BV-2 cells supplemented with minocycline was transferred to 661W photoreceptor cells to test whether minocycline may have a direct neuroprotective effect. After 48 h of incubation with microglia conditioned-medium, apoptotic cell death was analyzed by caspase 3/7 activity measurements. Data show mean ± SEM (n = 3/group, measured in duplicates) with *p < 0.05, **p < 0.01, ***p < 0.001