Tissue-engineered nerve graft and tetramethylpyrazine for repair of rat ischiadic nerve defect / 中华创伤杂志

ABSTRACT

Objective To evaluate the effect of tissue-engineered nerve graft combined with tetramethylpyrazine in the repair of ischiadic nerve defect in rats.Methods Fifty-five adult SD rats were allocated into groups A (n =15),B (n =15),C (n =15) and D (n =10),according to the random number table.All experimental sciatic nerves were at the right hind side.After the rats were anesthetized with 10 g/L pentobarbital through abdominal injection,a 1.5 cm nerve sciatic nerve was excised at the point 0.5 cm away from the lower margin of the piriformis.Four grafts were used to bridge the nerve defect,including tissue-engineered nerve transplanted neural stem cells (NSCs) that were cultured in medium containing tetramethylpyrazine for 1 week (group A),tissue-engineered nerve transplanted NSCs that were cultured in tetramethylpyrazine-free medium for 1 week (group B),acellular nerve allograft (group C),and nerve autograft (group D).After operation,group A was administered tetramethylpyrazine for 12 weeks in the operative site.For other groups,the same volume of normal saline was used instead of tetramethylpyrazine.Repair results were detected with the sciatic function index (SFI),nerve electrophysiological evaluation,fluorescent microscopy,horseradish peroxidas (HRP) retrograde tracer and nerve fiber regeneration study.Results At postoperative 2 weeks,no differences were found in SFI and electrophysiological evaluation among the groups,there was an intensive fluorescence in groups A and B and no fluorescence in group C,and large nestin-positive cells were observed in groups A and B.At postoperative 12 weeks,SFI was-17.52 ± 2.41 in group A,-25.74 ± 2.85 in group B,-36.12 ± 3.41 in group C and-15.87 ± 2.26 in group D;electrophysiological evaluation showed nerve conduction velocity of (9.43 ± 0.40) m/s in group A,(7.76 ± 0.31) m/s in group B,(5.87 ± 0.67) m/s in group C and (10.16 ± 0.39) m/s in group D;fluorescence microscope and histological staining showed NSCs could survive in vivo,migrate and differentiate into neurons and gliocytes;HRP-positive neurons were 885.40 ± 19.91 in group A,684.57 ± 38.37 in group B,390.33 ± 43.41 in group C and 941.67 ± 32.54 in group D;regenerated nerve fibers,often myelinated were large in group A.All the measures in group A were better compared to groups B and C (P ＜ 0.05),but didn't differ from those in group D (P ＞0.05).Conclusion Tissue-engineered nerve transplanted NSCs cultured in medium including tetramethylpyrazine can effectively repair rat sciatic nerve defect,and promote peripheral nerve regeneration and lower limb motor function recovery.