Length of warm ischemic tolerance for epithelial regeneration in heterotopic rat tracheal isografts

Objective To determine the length of warm ischemic (WI) tolerance in bronchial graft from non-heart-beating donors. Methods Forty-eight rats were randomly divided into 4 groups (each group having 12 rats) according to different WI durations including WI-0 min (group A), WI-30 min (group B), WI-45 min (group C) and WI-60 min (group D). In each group, the tracheae from 6 rats were respectively imbedded in greater omentum of other 6 rats, and 14 days later, the transplanted tracheae were taken from recipients to evaluate epithelial thickness and regeneration. Results Epithelial thickness and the degree of epithelial regeneration had no significant difference (P >0. 05) between the syngeneic control group and the WI-30 minutes group. All of the grafts with WI duration of 45 min were viable, but the epithelium was significantly thinner than that in the syngeneic control group (P<0. 05). However all of the grafts with WI duration of 60 min showed lower viability rate. Conclusion The time limits of tolerance to WI of tracheal grafts from NHBDs may be 45 min. Key words: Rats; Trachea;  Warm ischemia;  Epithelial regeneration