Tiam Mana Saffari

90 CHAPTER 5 MATERIALS AND METHODS Animal experiments were approved by the Mayo Clinic Institutional Animal Care and Use Committee (IACUC A3348-18). For this study, all animals were housed with ad libitum access to food and water, with a twelve-hour light-dark cycle after surgery. Experimental design In a total of 51 male Lewis rats, weighing between 250-300 grams (Envigo, USA), unilateral sciatic nerve gaps were repaired with three groups of nerve grafts. The experimental design of this study is depicted in Table 1. In group I (autograft), a unilateral 10-mm sciatic nerve gap was repaired with an ipsilateral reversed autologous graft to create a mismatch in the alignment of the nerve fibers (gold standard). For group II and III, decellularized processed nerve allografts were used to reconstruct the nerve gap. In group III, these nerve allografts were placed in a vascularized bed using a pedicled superficial inferior epigastric artery fascia (SIEF) flap 15 . Rats were sacrificed at two weeks (short-term), 12 and 16 weeks (long-term). Table 1. Experimental design. SIEF flap: Superficial inferior epigastric artery fascial (SIEF) flap. Groups Surgery Survival time 2 weeks (N) Survival time 12 weeks (N) Survival time 16 weeks (N) I Autograft 5 6 6 II Allograft 5 6 6 III Allograft + SIEF flap 5 6 6 Nerve allograft harvest and processing Seventeen Sprague-Dawley rats (Envigo, Madison, WI, USA), weighing 250-300 grams, served as donors for harvesting a 15-mm segment of the sciatic nerve bilaterally. The sciatic nerves were cleaned from external debris and processed using a five- day decellularization protocol 16 . Sprague-Dawley rats were used to obtain a major histocompatibility complex mismatch with the recipient Lewis rats 17,18 . Brief ly, rats were anesthetized in an isoflurane induction chamber and euthanized with an overdose of Pentobarbital Sodium (Fatal Plus, 390 mg/mL, Vortech, Dearborn, MI, USA). The nerves were harvested and collected in RPMI 1640 culture medium. After