Application of epineural sheath conduit for restoration of 6‐cm long nerve defects in a sheep median nerve model

Abstract

Background Due to limited number of studies, we tested feasibility of autologous epineural sheath conduit (ESC) in repair of 6‐cm median nerve gaps in a sheep—the large animal model. Materials and methods Eight ewes, 6–8 months old, 30–35 kg, were divided into three experimental groups: group 1—no defect repair (n = 4 nerves/group), group 2—autograft controls (n = 6 nerves/group), group 3—autologous ESC filled with saline (n = 6 nerves/group). ESC was constructed from a 6‐cm long segment of sheep median nerve and tested for expression of laminin B, Glial fibrillary acidic protein (GFAP), S‐100 and CD31 using immunofluorescent staining. At 6 months after nerve repair, nerve conduction velocity and somatosensory evoked potentials (SSEP) assessed neurosensory recovery, while histomorphometry tested nerve regeneration. Results Ex vivo characterization of ESC, before in vivo nerve gap repair, showed high laminin B expression, which supports axonal growth. At 6 months post‐repair, structural integrity of ESC was preserved. ESC was well‐vascularized and tissue adhesions were comparable to autograft controls. The maximal conduction velocities (29.80 ± 5.85 ms vs. 32.28 ± 6.75 ms; p = .44), action potential amplitudes (32.68 ± 17.44 mV vs. 44.14 ± 23.10 mV; p = .38) and SSEP amplitude values (6.18 ± 5.84 mV vs. 4.68 ± 2.53 mV; p = .28) were comparable between autograft and ESC groups. Presence of regenerating axons was confirmed in the distal segment of ESC at 6 months after repair. Conclusion The feasibility of ESC in restoration of 6‐cm long nerve defects in a sheep median nerve model was confirmed by nerve conduction assessments and correlated with axonal regeneration tested by histomorphometry. We confirmed ESC potential in support of regeneration of long nerve defects.

Influence of aging on the peripheral nerve repair process using an artificial nerve conduit

“…However, there are several problems with artificial nerve conduits. Decreased angiogenesis, a decrease in nerve fibers, and reduction of axon regeneration were previously reported in artificial nerve conduits when an artificial nerve conduit was used for a nerve defect that was long to a certain extent (4).…”

The advances in nerve tissue engineering: From fabrication of nerve conduit toin vivonerve regeneration assays

“…In most studies, on the basis of their frequency of usage (high vs. low), animals such as rats (Labroo et al, ; Tao et al, ), mice (Lin, Shea, et al, ; Yokoi et al, ), rabbits (Chang et al, ; Hsu, Chan, Chiang, Chen, & Jiang, ), dogs (Cui et al, ; Yao et al, ), cats (Kitahara et al, ), sheep (Siemionow et al, ), and monkeys (Zhang et al, ) are used (Angius et al, ).…”

Small Ruminants and Its Use in Regenerative Medicine: Recent Works and Future Perspectives

“…Even histologically, the nerves are polyfascicular just like humans [46]. Most works involving sheep are where the median or facial nerve is used, with a translational application in orofacial medicine or in hand surgery [47,48]. The nerves of the hind limb have not yet been the subject of many studies in this species, and those that exist are directed to the sciatic nerve [49] and its branches [50].…”