Effects of LLLT on LPS-activated microglial cells. SH-SY5Y cells were cultured (A) in the presence of LLLT-treated (20 J/cm2) LPS-activated BV-2 cells for 12, 24, and 48 h or (B) in the presence of the indicated doses of LLLT-treated BV-2 cells or primary microglia for 24 h. (A and B) Effector cells (microglia) were incubated with target cells (SH-SY5Y) at an E:T ratio of 8:1. After incubation, target cells that were double positive for CFSE and PI were analyzed by flow cytometry (n = 4; *P <0.05 and **P <0.05 versus corresponding control cells, #P <0.05 versus indicated cells). (C) BV-2 cells pretreated with or without PP1, then subjected to LLLT treatment, followed by western blot analysis of LPS-activated BV-2 cells received different doses of LLLT treatments to detect protein levels of iNOS. (D) Quantitative analysis of iNOS protein levels in treated cells. Data represent mean ± SEM (n = 4; *P <0.05 versus control cells, #P <0.05 versus indicated cells). CFSE, carboxyfluorescein diacetate succinimidyl ester; iNOS, inducible nitric oxide synthase; LLLT, low-level laser therapy; LPS, lipopolysaccharide; PI, propidium iodide.