A novel MyD88 inhibitor attenuates allograft rejection after heterotopic tracheal transplantation in mice.

Abstract Background After lung transplantation, the major complication limiting the long-term survival of allografts is obliterative bronchiolitis (OB), characterized by chronic rejection. Innate immune responses contribute to the development of OB. In this study, we used a murine heterotopic tracheal transplantation mouse model to examine the effects of a newtype of innate immune inhibitor, TJ-M2010–5. Methods Syngeneic tracheal grafts were transplanted heterotopically from C57BL/6 mice to C57BL/6 mice. Allografts from BALB/c mice were transplanted to C57BL/6 mice. The allograft recipients were treated with TJ-M2010–5, and anti-mouse CD154 (MR-1). The grafts were harvested at 7, 14, and 28 days and evaluated by histological and real-time RT-PCR analyses. Results In untreated allografts, almost all epithelial cells fell off at 7 days and tracheal occlusion reached a peak at 28 days. However, the loss of the epithelium and airway obstruction were significantly improved in mice treated with TJ-M2010–5 combined with MR-1. The relative mRNA expression levels of pro-inflammatory cytokines were upregulated in allogeneic tracheal grafts, and treatment with the two drugs reduced the production of pro-inflammatory cytokines and infiltration of inflammatory cells. Conclusions In heterotopic tracheal transplantation models, TJ-M2010–5 combined with MR-1 could ameliorate the development of OB. [ABSTRACT FROM AUTHOR]