Is Tracheal Transplantation Possible With Cryopreserved Tracheal Allograft and Hyperbaric Oxygen Therapy? An Experimental Study.

Background: Allografts have achieved prominence for tracheal reconstruction because of their natural physiologic and anatomic structure, which preserves respiratory tract flexibility and lumen patency. The immunomodulatory effects of cryopreservation prevent tracheal allograft rejection. In addition, hyperbaric oxygen therapy (HBOT) accelerates wound healing by promoting epithelization and neovascularization. This experimental study investigated the early and late effects of HBOT on cryopreserved tracheal allografts (CTAs).

Methods: The study used 33 outbred Wistar rats weighing 300 to 350 g as allograft transplantation donors and recipients. Among these, 22 recipient rats were randomly assigned to the HBOT (n = 11) and control (n = 11) groups. Rats in the HBOT group were treated with 100% oxygen for 60 minutes at 2.5 atmospheres of absolute pressure for 7 days. Recipient rats in both groups were euthanized at 1 week (n = 5) and 4 weeks (n = 6) after transplantation, defined as the early and late periods, respectively.

Results: In the early period, no significant histopathologic differences were observed between groups (p > 0.05). However, microscopic evaluation of the control group during the late period showed low epithelization of the CTA. In contrast, microscopic evaluation of the HBOT group during this same period revealed epithelium covering the transplanted CTA lumen. Significant epithelization and vascularization and significantly reduced inflammation and fibrosis were found in the HBOT group compared with the control group (p < 0.05).

Conclusions: HBOT may be effective in tracheal reconstruction by increasing epithelization and neovascularization after extended tracheal resection. HBOT, therefore, should be considered in CTA transplantation.