In vivo knockdown of intestinal DMT1 reduced reticulocyte counts and mitigated iron loading in Th3/+ mice. Reticulocyte counts (A), liver NHI (B), spleen NHI (C), serum NHI (D), serum ferritin (E), TSAT (F), and fecal lipocalin-2 levels (G) were quantified in 6-week-old male Th3/+ mice that had been treated with saline, empty NPs (FA-GDLVs), or with FA-GDLVs carrying NC, or DMT1 siRNA daily for 16 days. Data are presented as mean ± SD for n = 4 to 5 mice per group and were analyzed by 1-way ANOVA followed by Tukey multiple comparisons test. Groups labeled with different letters are significantly different from one another. Treatment main effects: P < .001 for panel E; P < .01 for panel B; P < .05 for panels A,C-D,F.