CXCR4 antagonist reduces epithelial loss and trachea occlusion. C57BL/6 mice were transplanted heterotopically with C57BL/6 (isograft) or BALB/c (allograft) trachea. In allograft group, half of the mice were injected daily with 160ng/g of CXCR4 antagonist TN14003, a 14 amino acid peptide with loop structure. Tracheal grafts were harvested on days 10 and 42 post-transplant, stained with H&E (figure 2A, 2B) and percentage of trachea occlusion determined on day 42 (figure 2C). Values represent mean ± standard error. n=4, *, p<0.05.