Mean foreskin keratin thicknesses by donor and region.
(A) Representative image of intra-individual variation in keratin thickness (outer foreskin). White ‘⁁⁁⁁’ symbols show areas of thinner keratin and white solid triangles show areas of thicker keratin. Involucrin (green), filaggrin (red), cell nuclei (blue). Inset: magnification of boxed area with only filaggrin staining (red) shown; scale depicts thickness in microns. (B) Illustration of foreskin regions examined: inner (red), frenar band (yellow), and outer (green) foreskin. Whisker and boxplots of individual keratin measurements demonstrating distribution of thicknesses. Median = middle line, box = 25–75th percentiles, whiskers = 5–95th percentiles, mean = ‘+’ symbols, outliers not shown for ease of viewing. *p<0.05, **p<0.001. (C) Correlation of mean regional measurement per donor. Each symbol represents mean thickness calculated for one donor. Light gray boxes/line = inner: frenar band ratio and dark gray circles/line = inner: outer ratios.
