Fig. 5. Reduced apoptosis in adult 3-integrin-deficient skin grafts. Longitudinal sections through WT (A,C) and 3-integrin deficient (B,D,E) adult skin grafts were examined for apoptosis by TUNEL detection. Sections were double labelled with propidium iodide (PI) to detect cell nuclei (A', B', C', D' and E', respectively). Apoptotic cells were very rarely detected in either WT (A and A') or 3-integrin-deficient (B and B') interfollicular epidermis. In hair follicles the numbers of TUNEL-positive cells were significantly reduced in 3-integrin-deficient skin grafts (D) compared with WT controls (C). Clusters of hair follicles in the 3-integrin deficient samples had very few numbers of TUNEL-positive cells (E and E'). Eight skin grafts for each genotype were analysed and the experiment was repeated three times. Over 320 follicles per genotype were analysed. (F) Quantitation of the percentage of hair follicle keratinocytes with TUNEL-positive signals ± s.e.m.; n=5-6 per genotype; P*<0.005. Bar, 50 µm (A,B,E); 100 µm (C,D).