Figure 2.

4-nitroquinoline-1-oxide (4NQO)-induced mouse model of oral squamous cell carcinoma (oSCC). (A) Schematic of the experimental design. Female (N = 50) and male (N = 50) mice received either 4NQO or propylene glycol (vehicle) in the drinking water ad lib for 16 weeks. The mice were monitored for oral lesions for an additional 12 weeks. Gnawing function was quantified weekly with a dolognawmeter. Tongue tissues were then processed for histopathology and flow cytometry. (B) Representative hematoxylin & eosin stained tongue sections from a vehicle-treated (tx) male mouse (a; 4× with 10× inset), male mouse with 4NQO-induced papillary lesion (b; 4× with 10× inset) on the posterior tongue, and invasive lesion (c; 4× with 10× inset) on the anterior tongue. (C) Pooled data from 15 female and 16 male mice with 4NQO-induced lesions occurring on posterior tongue, anterior tongue, ventral tongue and buccal mucosa. Data represented as a percent of total mice by sex. (D) Functional allodynia was analyzed as mean gnaw-time across mice with 4NQO-induced oSCC or vehicle-treatment over time (weeks). Pooled data from female (red circles) and male (blue circles) mice with 4NQO-induced oral SCC (4NQO-Tx) and vehicle-treated mice (Vehicle-Tx, squares) over time analyzed by Three-way analysis of variance (ANOVA). Holm-Sidak post hoc comparisons for Sex by Time, ^#P < 0.05, ^##P < 0.01; Time by Treatment, *P < 0.05, **P < 0.01.