[The early changes of respiratory system resistance and γδT lymphocytes infiltrated in graft after lung transplantation of mouse].

Objectives: To generate an orthotopic left lung transplantation model in mice, and to observe the early changes of respiratory system resistance and γδT lymphocytes infiltrated in grafts. Methods: The research time was from March 2014 to May 2015. The male C57BL/6 mice ( n =35) and BALB/c mice (syngenic group, n =10) were randomly divided into five groups. Control group ( n =5): wild C57BL/6 mice; syngenic transplant group ( n =10): C57BL/6→C57BL/6; allogenic transplant group(allogenic group, n =10): BALB/c→C57BL/6; each transplant group was randomly divided into 3-day and 7-day subgroups ( n =5). Respiratory system resistance and histological features of grafts were assessed, and differences in graft infiltrating γδT lymphocytes and mRNA expression of interleukin (IL)-17A were quantified on 3 and 7 days after transplantation. Multiple comparisons were performed using one-way analysis of variance and least significant difference analysis. Results: (1) The respiratory system resistance of syngenic group and allogenic group were (2.61±0.59) cmH ₂ O·s/ml and (2.84±0.31) cmH ₂ O·s/ml 3 days post-operation, both of them increased compared to control group (1.39±0.17) cmH ₂ O·s/ml (1 cmH ₂ O=0.098 kPa) ( P =0.001, 0.000). The respiratory system resistance of allogenic group were (4.33±0.67) cmH ₂ O·s/ml 7 days post-operation, which was significantly higher than that of syngenic 7-day subgroup (1.87±0.27) cmH ₂ O·s/ml and control group (1.39±0.17) cmH ₂ O·s/ml ( P =0.000, 0.000). (2) The isografts of syngenic group showed a relatively normal histological appearance with minimal infiltration of inflammatory cells, and the allografts of allogenic group infiltrated apparently by inflammatory cells, especially 7-day subgroup showed acute cellular rejection. (3) The percentage of γδT lymphocytes infiltrated in isografts and allografts were 3.90%±0.86% and 4.40%±0.57%, respectively, which were significantly increased compared to that of control lungs 2.00%±0.23% 3 days post-operation( P =0.000, 0.000); The percentage of γδT lymphocytes infiltrated in 7 days allografts was 5.40%±0.98% , which was higher compared to that of 7 days isografts 2.60%±0.54% and control lungs 2.00%±0.23% ( P =0.000, 0.000). (4) IL-17A mRNA expression levels were 3.37±0.55 and 5.23±1.50 in isografts and 6.77±0.93 and 27.32±4.20 in allografts, on postoperative day 3 and 7 respectively. All of them were significantly upregulated compared to that of control lungs 0.99±0.08 ( P =0.000, 0.000), and allografts exhibited significantly greater IL-17A transcript levels compared to isografts on postoperative day 3 and 7 ( P =0.000, 0.000). Conclusion: The rise of respiratory system resistance of lung grafts after transplantation may relate to the increased IL-17A-producing γδT lymphocytes infiltrated in the grafts.