Epithelial Kinetics In Mice With Obliterative Airway Disease Following Trachea Transplantation

Objective To establish an obliterative airway disease animal model and explore the epithelial kinetics following trachea transplantation.Method Allografts and isografts were obtained by transplanting BALB/c tracheas into C57BL/6(GroupⅡ,Ⅲ) and BALB/c(GroupⅠ), respectively. Grafts were transplanted into a subcutaneous pouch in the dorsal surface of recipient mouse.GroupⅢwere injected with cyclosporin 25mg/kg/day intraperitoneal, from the first day post-implantation to the day of graft harvest. Animals were harvested at days 3, 7, 14, 21 and 30 after trachea transplantation. BrdU injection occurred on the day of graft harvest as outlined below. Grafts were removed for histology, computerized morphometry, BrdU labelling index and TUNEL positive cells.Results Morphometry:In groupⅠ,on day 3 epithelium minor injuried and mucosal edema. On day 7, 14, 21 after transplantation, gradually epithelium recovered normal, mucosal edema lessen and recovered normal. on day 30 epithelium approached to normal; In groupⅡ, on day 3 after transplantation epithelium minor injuried , epithelium segregated lamina propria partly and mucosal edema. On day 7, 14, 21 cilia lost, epithelium slough and necrosis with abundant fibrous tissue and lymphocyte. On day 30 epithelium completely disappeared. Lumens were obturated by fibrous tissue and obliterated. In groupⅢ, epithelium minor injuried , epithelium segregated lamina propria partly and mucosal edema on day 3 after transplantation. On day 7, 14, 21 cilia lost, epithelium slough and necrosis with abundant fibrous tissue and lymphocyte. On day 30 cilia lost, epithelium slough and necrosis with abundant fibrous tissue and lymphocyte. Fibrous tissue and lymphocyte were less than GroupⅡ. Proliferation of fibrous tissue obviously, but a little epithelium can be seen. Lumens were obturated by fibrous tissue and obliterated. On day 3 after transplantation the percentage of ciliary coverage in the three group was similar(p>0.05) and greater than 90%. On day 7 after transplantation the percentage of ciliary coverage of groupⅠ,ⅡandⅢwas 94% and 80%, respectively. the percentage of ciliary coverage of groupⅠwas much more than that of groupⅡand groupⅢ(p=0.000,p=0.001).. On day 14 after transplantation the percentage of ciliary coverage of groupⅡandⅢwas 55% and 71%,. respectively . The percentage of ciliary coverage of groupⅡandⅢwas much less than that of groupⅠ(p=0.000,p=0.000). The percentage of ciliary coverage of groupⅡwas signifiance compared to groupⅢ.On day 21 after transplantation the percentage of ciliary coverage of groupⅡandⅢwas 15% and 63%,. respectively . The percentage of ciliary coverage of groupⅡandⅢwas much less than that of groupⅠ(p=0.000,p=0.000). On day 30 after transplantation the percentage of ciliary coverage of groupⅡandⅢwas less than 5% and much less than groupⅠ(p=0.000). The extent of BrdU labelling index of groupⅠwas 3～5%. On day 3 after transplantation groupⅡwas signifiance compared to that of groupⅠandⅢ.On day 7 after transplantation BrdU labelling index of groupⅡwas 15%,and much more than that of groupⅠandⅢ(p=0.000,p=0.001). The peak of BrdU labelling index of groupⅡandⅢwas on day 14 , groupⅡwas signifiance compared to that of groupⅠand groupⅢ(p=0.000, p=0.000). On day 21 after transplantation BrdU labelling index of groupⅡwas much more than that of groupⅠandⅢ(p=0.000,p=0.002). On day 30 after transplantation BrdU labelling index of groupⅡandⅢdegraded obviously, and especially the groupⅡ. The extent of TUNEL positive cells of groupⅠwas 3～4.On day 3 after transplantation TUNEL positive cells of the three group was similar (p>0.05). On day 7 after transplantation TUNEL positive cells of groupⅡandⅢwere much more than groupⅠ(p=0.000,p=0.000). The peak of UNEL positive cells of groupⅢwas on day 14 ,and TUNEL positive cells of groupⅡand groupⅢwas much more than that of groupⅠ(p=0.000,p=0.000). The peak of UNEL positive cells of groupⅡwas on day 21 after transplantation , and TUNEL positive cells of groupⅡand groupⅢwas much more than that of groupⅠ(p=0.000,p=0.000). On day 30 after transplantation TUNEL positive cells of groupⅠwas similar with groupⅡand groupⅢ(p=0.613, p=0.061).Conclusion 1.In the alloimmune environment, impaired airway epithelium increased proliferation of numerous airway epithelial cells. Numerous S phase airway epithelial cells unable to progress through mitosis and shunted into an apoptotic pathway. The allograft epithelium by actively regenerating serves as a self-renewing source of antigen, and thus increase the injury of airway epithelium .Airway epithelium growed arrest and accelerated apoptosis,so this leaded to OAD.2.Cyclosporin delays but does not eliminate fibration ,and its protectiong of airway epithelium was limited.