Tail morphology in B6 and A/J
The tails of the mice were examined for differences that might account for the variations in the bleeding and rebleeding values. Sections of the tail from the B6 and A/J mice were stained with Hematoxylin/Eosin or Masson's Trichrome and representative sections are shown in Figure 3. No obvious qualitative differences were observed in hair follicles, sebaceous glands, or center bone/cartilage in Hematoxylin/Eosin (Figure 3A) stained sections. Sections of the tails were stained with Masson's Trichrome (Figure 3B) that detects collagen, the major platelet adhesive substratum for initiation of thrombus formation. Collagen content (% tail area) was quantified (Figure 3C) from 3–4 sections from 2–3 areas/mouse. The amount of collagen was greater in the A/J than the B6 mice (P < 0.05). Collagen in vessels in adipose tissue in the A/J mice is also increased compared to the B6 mice (data not shown).
Figure 3  Tail morphology and collagen. Tails were excised, embedded in OCT, sectioned, and stained with Hematoxylin/Eosin or Masson's Trichrome. Panel A: Representative sections stained with hematoxylin and eosin from B6 and A/J mice. Panel B: Representative sections stained with Masson's Trichrome from B6 and A/J mice. The blue color identifies the collagen. Panel C: The percentage of the collagen area (excluding center bone/cartilage) of the total tail area of each section was determined in 3–4 sections at 2–3 sites for each tail and averaged for each mouse. Values are the mean ± SEM of 4–8 mice per genotype. Symbol indicates a significant difference (*P < 0.05) between B6 mice determined by t-test.