Experimental study of repairable length of nerve defects with acellular nerve allografts / 中国矫形外科杂志

ABSTRACT

[Objective]The purpose of this paper is to demonstrate whether the nerve length could affect the quality of acellular nerve and investigate the properly repairable distance of nerve defects with acellular nerve allografts.[Method]Fresh sciatic nerves were obtained from adult dogs and divided into 12 cm long segments.The nerve segments were decellularized via an improved chemical decelluarization treatment as following Nerve segments were rinsed with cold sterile Ringer's solution and submergedin 5% Triton-100 solution 12h,and then soaked the nerve segments into 5% sodium deoxycholate for 12h.The treated nerve segments were washed in distilled water for 3h.This procedures were repeated once again.In vitro,the degrees of decellularization,demyelination and integrity of nerve fiber tubal of chemically extracted acellular nerves were observed with microscope and assessed by a score system.In vivo,the sciatic nerve of dogs on the right was exposed.In 8 cm grafted group(n=6),a 7 cm segment of sciatic nerve was removed from the midthigh level.In 10 cm grafted group(n=6),a 9 cm segment of sciatic nerve was removed at the same level.The gaps were bridged with acellular nerve allografts by 8 cm and 10 cm long segments respectively.The follow-up period was 12 month postoperatively.Motor functional recovery of the right hind following allografting was examined by neurobehavioral,electrophysiological,histological and immunohistochemical assessment.[Result]There was no difference on the degrees of decellularization,demyelination and integrity of nerve fiber tubal among every fraction of the acellular nerve from the two ends to the central portion.In 8 cm grafted group,all survival dogs(n=5) were held upright with the affected hindlimb extended so that the body's weight was supported by the distal metatarsus and toes.In 10 cm grafted group,animals were failed to held upright with the affected hindlimb.Electrophysiological studies showed that elctromyographic activity was observed in both groups.After 12 month the conduction velocity was 32.1+5.1 m/s in 8 cm grafted animals and 18.3+6.0m/s in 10 cm grafted group.In normal animals, the conduction velocity was 106.6+16.4 m/s.The conduction velocity in 10 cm grafted group was lower than 8 cm grafted(P