4-NQO exposure induces precancerous alterations in mouse mandibular lymph nodes.

<p><b>A–C.</b> Images of dissected H&E and whole animal HF US (ultrasound) mandibular lymph nodes from representative age-matched (AM) control (<b>A</b>), 4-NQO-treated (28 wk) (<b>B</b>) and Fasl (<b>C</b>) mice. Lymph node borders in the HF US images are indicated in yellow. Vascular flow identified by power Doppler imaging is shown in red. Power Doppler flow dynamics for each condition are visualized in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100185#pone.0100185.s004" target="_blank">Video S2</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100185#pone.0100185.s006" target="_blank">S4</a>. H&E scale bar = 250 µm, ultrasound scale bar = 1 mm. CP, Cheek Pouch. <b>D&E.</b> Analysis of lymph nodes by HF US. 4-NQO treated mice at 0 and 28 wk were imaged after 8 week 4-NQO treatment and study end point. B6 age-matched (AM) Ctl 0 and 28 wk mice were imaged at the same age as 4-NQO treated mice. The Fasl lymph node data is included for comparison. <b>D.</b> 4-NQO exposure induces increased mandibular lymph node volume. <b>E.</b> 4-NQO exposure increases vascular flow in mandibular nodes. N = 6 lymph nodes from 3 mice per group, except for the controls, where N = 8 lymph nodes were analyzed from 4 mice. Box and whisker plots show minimum, 25^th, median, 75^th and maximum values, respectively. *, p≤0.05.