FIG. 6.

Quantitative analysis of NOS2 expression in Iba-1–positive microglial cells reveals regionally and developmentally distinct patterns of microglial reactivity following exposure to Mn. The percentage of Iba-1–positive microglia expressing NOS2 was determined in mice exposed to 0, 10, or 30 mg/kg MnCl₂ by daily intragastric gavage as (A) juveniles, (B) adults, and (C) both juveniles and adults in the St, Gp, and SNpr. Three serial sections were stained for each brain region per hemisphere from an average of three mice per treatment group. For quantitative cell counts, three microscopic fields were evaluated per brain region from each serial section, totaling n = 9 per treatment group. Data represent the mean percentage of Iba-1–positive microglia expressing NOS2. Different letters denote significant differences between treatment groups, p < 0.05.