Enlargement of cutaneous lymphatic vessels during acute inflammation. (A-B) Quantitative image analyses of CD31+/LYVE-1+ lymphatic vessels in the ear skin of mice revealed a significantly increased number per millimeter basement membrane (BM, A) and size (B) of lymphatic vessels in untreated K14-VEGF-C Tg mice, compared with untreated wild-type mice (n = 3 mice per group). The lymphatic vessel size was also increased in untreated K14-VEGF-D Tg mice, compared with untreated wild-type mice (n = 3 mice per group). The average number of lymphatic vessels in wild-type mice was not significantly different at 2 days after oxazolone challenge (2-day oxa) compared with untreated wild-type mice. The lymphatic vessel number was also not significantly different between untreated and oxazolone-challenged K14-VEGF-C and K14-VEGF-D Tg mice, respectively (A; wild-type, n = 10; K14-VEGF-C, n = 5; K14-VEGF-D, n = 5). At 2 days after oxazolone challenge, the average size of lymphatic vessels was significantly increased in K14-VEGF-C, K14-VEGF-D Tg, and wild-type mice, compared with untreated mice of the same genotype (B). (C) Representative images of CD31+/LYVE-1+ lymphatic vessels (green) in the ear skin. CD31+/LYVE-1− structures represent blood vessels (red). The positive staining of LYVE-1 in the stratum corneum in panel C is unspecific. Bars represent 100 μm. (D-E) The average lymphatic vessel number (D) and size (E) were significantly increased in the back skin of untreated K14-VEGF-C and K14-VEGF-D Tg mice, compared with untreated wild-type mice. At 2 days after UVB irradiation (2-day UVB), lymphatic vessel size (E), but not lymphatic vessel number (D), was significantly increased in K14-VEGF-C, K14-VEGF-D, and wild-type mice compared with untreated mice of the same genotype. (A-B,D-E) Data are mean ± SD. ‡P ≤ .05. ‡‡P ≤ .01. ‡‡‡P ≤ .001. ns indicates not significant versus untreated wild-type. *P ≤ .05. **P ≤ .01. ***P ≤ .001. ns indicates not significant versus untreated mice (untreated wild-type vs 2-day oxa/2-day UVB wild-type; untreated VEGF-C vs 2-day oxa/2-day UVB VEGF-C; untreated VEGF-D vs 2-day oxa/2-day UVB VEGF-D).