Figure 4.

Low-dose CO modulates macrophage polarization in kidneys from RTV-exposed wt mice. Subsets of F4/80⁺ CD11b⁺ macrophages, expressed as a percentage of CD45+ leukocytes (A-C) were examined in RTV-exposed wt mice either untreated or following CO inhalation. RTV had no effect on the fraction of total leukocytes (B) or total macrophages (C), whereas CO inhalation significantly increased both populations (B,C). RTV markedly elevated the pro-inflammatory CD45⁺/F4/80⁺ I-A/E⁺ M1 subset, which was reduced significantly by CO (D). RTV also increased the number of CD45⁺/F4/80⁺ CD206+ M2 cells as a proportion of total macrophages, an effect amplified by CO (E). The CO-mediated alteration in M2 cells predominantly involved augmentation of regulatory, anti-inflammatory CD45⁺/F4/80⁺ B7-H4⁺ M2c cells (F).