An Anatomical Murine Model of Heterotopic Periorbital Subunit Transplantation

Background: Conventional reconstructive methods fail to achieve satisfactory results in total eyelid defect cases. Vascularized composite tissue allotransplantation might provide both good appearance and function for these patients. The structure of the eyelid is exceptional because it simultaneously consists of skin, connective tissue, the striated muscle, fiber structure, aponeuroses, and mucosa. Thus, before clinical application of eyelid allotransplantation, more experiments are needed to clarify the impact of ischemia, immunal suppressive agents, and deinnervation effects on these sophisticated structures. We developed an heterotopic periorbital transplantation model in rats to facilitate further experiment in this field. Methods: Twenty-five inbred male Lewis rats were used for anatomy study (n=10), and as donors or recipients of the operations (n=10). In the anatomy study, the vascular distribution and innervation to the periorbital unit was identified and recorded. Then, according to the anatomy study, 10 heterotopic transplantations and 2 transplantations with pedicle ligated were performed. The posterior facial vein and the external carotid artery are selected as the graft pedicle. All transplanted eyelids were assessed daily. Micro-CT scanning and hematoxylin and eosin staining of the grafts were performed 60 days after the operation. Results: All recipients tolerated the operation well. All grafts without pedicles ligated survived and new hair growth was observed. All of the transplanted eyelids were pink and pliable during the entire observation period, and we did not observe any signs of arterial or venous occlusion. In the recipients with graft pedicle ligated, the grafts were necrosed and mummified within 4 to 5 days. MicroCT of the survived grafts showed good blood supply and histologic staining revealed normal histologic morphologies. Conclusions: Our study proved the anatomical feasibility of periorbital transplantation by establishing a heterotopic transplantation model, which might facilitate future eyelid allotransplantation-related experiments.

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