The LV network and lymphatic drainage are compromised in IL-7Rα^−/− mice. (A-E) The LYVE-1⁺ lymphatic network in the ear skin of IL-7Rα^−/− and WT control mice was analyzed in whole mount preparations. (A) Representative images showing LYVE-1⁺ LVs in the ear skin of both genotypes. Scale bar represents 200 μm. (B-E) Image-based morphometric analysis revealed a significant decrease (B) in average LYVE-1⁺ vessel diameter, whereas the average LYVE-1⁺ area (C) was increased in the ear skin of IL-7Rα^−/− compared with WT mice. (D) The number of branching points was significantly increased, whereas the (E) distance between branching points was decreased in IL-7Rα^−/− compared with WT mice. (F-G) To evaluate lymphatic drainage function, Evans blue dye was intradermally injected into the ears of IL-7Rα^−/− and WT mice, and the dye content remaining in the ear was extracted and quantified 16 hours later. (F) Quantification detected increased Evans blue levels in the ears of IL-7Rα^−/− mice, indicative of defective lymphatic drainage. (G) Representative pictures taken 16 hours after Evans blue injection. Pooled data from 2 similar experiments involving a total of 10 mice/group are shown. *P < .05; **P < .01; ***P < .001.