Effect of ARIs and AR deficiency on LPS-induced cytokine secretion. Macrophages and RMG were incubated with vehicle, BGG (50 μM), or Sorbinil (10 μM) for 24 hours in the absence or presence of LPS (20 ng/mL) for 4 hours. The cytokines in culture medium from macrophages (A, D) or RMG (B, E) were measured by ELISA. (C) Western blotting demonstrated that AR expression was reduced by siRNA in macrophages or gene knockout in RMG. (D) Aldose reductase expression was reduced in Raw264.7 cells by siRNA. (E) Retinal microglia were isolated from wild-type or AR-knockout mice. Both knockdown and knockout cells were treated with LPS for 4 hours before harvest. In (A) and (B), * compares vehicle versus ARI in LPS treatment. # compares LPS and no LPS between vehicle-treated groups. In D, # compares LPS versus no LPS treatment; * compares AR versus control siRNA treatment in LPS-treated group. In E, # compares LPS versus no LPS treatment; * compares wild-type and ARKO in LPS-treated group. Data are represented as the Mean ± SEM (N = 3). *, #P < 0.05; **, ##P < 0.01; ***, ###P < 0.005.