Morphological features of allogenic nerve segment in rats after subcutaneous embedment

Mingtang Gao; Dianming Jiang

摘要：BACKGROUND: Some studies demonstrate that allogenic peripheral nerve segment embedded subcutaneously significantly reduce the infiltration of lymphocyte and decrease immunological reaction.OBJECTIVE: To observe the gross shape, optical and electron microscope results of allogenic nerve segment in rats 2 weeks after subcutaneous embedment, and compare with subcutaneous emdedment of autologous nerve segment.DESIGN: A randomized and controlled experiment.SETTING: Department of Orthopaedics of Fifth People's Hospital of Zhengzhou; Department of Orthopaedics,First Hospital Affiliated to Chongqing Medical University MATERIALS: Totally 30 adult healthy Wistar male rats, with body mass of (200±20) g, were enrolled. Ten rats were chosen as the donors of allogenic nerve transplantation. The other 20 rats were randomly divided into 2 groups: allogenic nerve embedment group and autologous nerve embedment group, with 10 rats in each one.JEM-1220 transmission electron microscope (Japan) and Olympus BX50 optical microscope (Japan) were used.METHODS: This experiment was carried out at the laboratory of Orthopaedic Department, Chongqing Medical University from October 2000 to April 2002. ① Sciatic nerve of donor rats for allogenic nerve transplantation was cut off at 5 mm distant from pelvic strait.15 mm sciatic nerve segment was chosen from lateral part as graft. Allogenic nerve embedment group: 15 mm sciatic nerve form the donor rats was embedded in the posterior part of right legs. Autologous nerve embedment group: 15 mm sciatic nerve segment of autologous left side was embedded in the posterior side of right legs. ② Nerve segment embedded subcutaneously was taken out at postoperative 2 weeks and performed gross observation; then 5 samples chosen randomly respectively from 2 groups and given haematoxylin-eosin staining and observation under optical microscope (×400);The other 5 samples were made into ultrathin sections (0.5 μm)and observed under transmission electron microscope ( × 17 000).MAIN OUTCOME MEASURES: Gross shape, optical and electron microscope results of nerve segments of rats between two groups at 2 weeks after subcutaneous embedment.RESULTS: ① Results of gross observation: Appearance of nerve segment was similar between 2 groups. ②Results of optical observation: medullary sheath denaturation, axonotmesis, vascular engorgement, desmoplasia of adventitia and infiltration of inflammatory cells were all found in both 2 groups. Inflammatory reaction was a little more severe in the allogenic nerve embedment group than in the autologous nerve embedment groups.③Results of electron microscope: Similar cataplasia and denaturation of medullary sheath and cataplasia of Schwann cell were all found in the 2 groups.CONCLUSION: Some inflammatory reaction occurs after allogenic nerve embedment, but the activity of Schwann cell is similar to that of peripheral nerve after autologous nerve embedment.