Figure 4

LPS-Induced Arginase 1 Activation in rTg4510 and nontransgenic mice. rTg4510 mice or non-transgenic (nTg) littermates were injected with LPS or vehicle, and sections were stained using immunohistochemistry for the microglial marker arginase 1. Digital images from the anterior cortex (A-D) of nontransgenic (A, C) or rTg4510 mice (B, D) injected with vehicle (A, B) or LPS (C, D), from CA1 of nontransgenic (F, H) or rTg4510 mice (G, I) after injections of vehicle (F, G) or LPS (H, I), or entorhinal cortex (ECX) of nontransgenic (K, M) or rTg4510 mice (L, N) after vehicle (K,L) or LPS (M,N) injections are presented. Panels E, J, and O display mean ± S.E.M (n = 6-8) of % Area for immunostaining of arginase 1 positive microglia (black) in the anterior cortex, CA1 CX, and ECX respectively. Arginase 1 staining increased in both rTg4510 and nontransgenic littermates in cortex, CA1, and ECX after treatment with LPS compared to vehicle- treated mice, and the magnitude of the induction was similar in rTg4510 and nontransgenic mice. Statistical analysis was performed using 2-way ANOVA followed by Fisher's PLSD multiple comparison test (*p < 0.05), n = 6-8. Scale bar represents 20 μm.