Rejection and expression of thioredoxin in transplanted canine lung

Thioredoxin (TRX) production has been shown to be induced by a variety of stresses. In this study, we examined TRX expression in lung tissues after canine lung transplantation to determine whether it could be induced by allogenic stimulations and could be used to diagnose early rejection. Thirty-five adult mongrel dogs were used in all. In group A, 24 dogs underwent allotransplantation of the left lung with no immunosuppressant and were sacrificed at various times; 5 were sacrificed on postoperative day (POD) 1; 5 on POD 2; 7 on POD 3; and 7 on POD 5. In group B, 5 donor right lungs were used for negative control. In group C, 3 dogs underwent autotransplantation. In group D, 8 dogs underwent allotransplantation of the left lung with optimal immunosuppression and were sacrificed at POD 28. Lung tissues were stained with anti-TRX antibody, and the TRX high-producer (TRXh) cells in a randomly chosen field were counted as the index of TRX expression. In group A, the number of TRXh cells were as follows: 1.68 +/- 1.14 in grade 0; 4.87 +/- 1.07 in grade 1; 10.42 +/- 4.24 in grade 2; 27.34 +/- 17.96 in grade 3; and 50.90 +/- 17.36 in grade 4. In group B, the number of TRXh cells was 1.82 +/- 1.01. There was a significant difference between each rejection grade in group A and group B (p < 0.01), and we could observe TRXh cells in the early stage of rejection. These results suggest that analysis of TRXh cells in lung tissues may be useful in the early diagnosis of rejection.