Figure 3.

MCP-1 reduces excitotoxicity. A, Primary neurons were treated for 24 h with the indicated concentrations of MCP-1, then preloaded with Fluo-4 A.M. and incubated with glutamate (200 μm). As a control neurons were incubated with glutamate together with the NMDA-R antagonist MK801 (“MK,” 10 μm). The fluorescence signal was measured after 3 min. The data are mean ± SE of n = 12 replicates and is Ca²⁺ entry relative to that measured in the presence of glutamate alone. *p < 0.05, **p < 0.005, ***p < 0.0001 versus glutamate alone. B, Primary neurons were incubated with 0 (Ctrl) or 200 μm glutamate and the indicated concentrations of MCP-1, and the cellular ATP levels were measured 24 h later. Data are mean ± SE of n = 12 replicates and is the ATP level relative to control cells. ^§§§p < 0.0001 versus control; *p < 0.05, **p < 0.005, ***p < 0.0001 versus no MCP-1. C, Primary neurons were incubated with NMDA (20 μm) or glutamate (100 μm) in the presence of the indicated concentrations of MCP-1. After 48 h, neuronal viability was assessed by measurement of LDH in the media. Data are mean ± SE of n = 8 replicates and is the LDH released compared with control (CTL; nontreated cells). ^§p < 0.05 versus control; ^§§§p < 0.0005 vs control; **p < 0.005 versus NMDA alone or versus glutamate alone. In control cells, 100% LDH reflected 20 ± 1.4% of total LDH released after 48 h (mean ± SE of n = 15 individual measurements).