Abstract: BACKGROUND: Finding a tarsal substitute is the key to eyelid reconstruction, but current materials exist insufficiency. According to the biological characteristics of autologous tendon, it has the potential as a tarsal substitute.  
OBJECTIVE: To observe the effect and histopathological changes of autologous tendon as a tarsal substitute transplanted for eyelid reconstruction in rabbits.
METHODS: Eyelid defect models on the lower eyelids of 13 healthy New Zealand white rabbits were prepared. The eyelid reconstruction in situ was performed autologous tendon in the right lower eyelids (tendon group) and allogeneic sclera material (sclera group) on the upper eyelids of fellow eyes. The changes of eyelids were observed every day after operation. After 4 weeks, bilateral meibomian complexes were taken for biomechanical test and hematoxylin-eosin staining to observe vascularization and complex outcome.  
RESULTS AND CONCLUSION: (1) After operation, the bilateral eyelid incision of the rabbit had slight redness, swelling and conjunctival hyperemia, which subsided in approximately 5 days. The incision healed well at 4 weeks after implantation. There was no obvious rejection of the implant, graft exposure, or eyelid closure obstacle. The cornea was intact. Eye movement was good. (2) Hematoxylin-eosin staining exhibited that the graft in the tendon group had a clear border, and the periphery was surrounded by meibomian gland cells. Collagen fibers in the center of the graft were seen in a cord-like parallel arrangement. Part of the fibrous structure at the border of the tendon was unclear. New capillaries were scattered around the graft, and there was no obvious inflammatory cell infiltration around the graft. In the allogeneic sclera group, the allogeneic sclera was replaced by collagen fibers, and the cells were disorderly arranged. (3) The maximum load of the eyelid was (10.521±3.497) and (9.450±4.032) N in the tendon group and allogeneic sclera group, respectively. The tensile displacement at the maximum load was (6.110±0.347) and (4.590±0.732) mm in the tendon group and allogeneic sclera group, respectively. Young’s modulus of elasticity was (5.562±1.156) and (2.575±0.978) MPa in the tendon group and allogeneic sclera group, respectively. There were significant differences between groups (P < 0.05). (4) Autologous tendon has a good histocompatibility with tarsal plate, which can achieve the physical characteristics and reconstruction effect of eyelid in situ reconstruction. 

Key words: eyelid reconstruction, autologous tendon, allogeneic sclera, tissue engineering, in situ reconstruction, rabbit, animal model