Effect of tetramethylpyrazine on biological properties of tissue-engineered acellular nerve allografts

Xiang Fei-fan; Yang Yun-kang

doi:10.3969/j.issn.2095-4344

Abstract：BACKGROUND:Increasing studies have shown that tetramethylpyrazine can play certain immunosuppressive effects on cels and alogeneic nerves, reduce the infiltration of inflammatory cels, and reduce the body’s immune rejection to nerve alografts. <br> OBJECTIVE:To observe the effect of tetramethylpyrazine on the biological characteristics of tissue-engineered nerve bridging materials. <br> METHODS:Acelular sciatic nerves were extracted from Wistar rats using chemical method to construct gene-modified nerve alografts that were cultured in complete medium containing 200 mg/L tetramethylpyrazine or not for 1 week to observe the cel distribution and structure. Twenty-four healthy adult male Sprague-Dawley rats were enroled and randomly divided into four groups: in nerve xenograft group, sciatic nerve segments from Wistar rats cultured at 4℃ for 1 week were implanted subcutaneously into the back of Sprague-Dawley rats; in control group, tissue-engineered nerve segments cultured in the complete medium were implanted; in experimental group, tissue-engineered nerve segments cultured in the complete medium containing 200 mg/L tetramethylpyrazine were implanted; in nerve alograft group, nerve alografts from Sprague-Dawley rats were implanted. After 7 days, nerve segments were taken out for hematoxylin-eosin staining under light microscope, and the number of CD4+ and CD8+ lymphocytes was counted. <br> RESULTS AND CONCLUSION:The acelular nerve segments with no celular constituents had intact epineurium and basement membrane. After injection of nerve cels, there were more celular components that distributed unevenly beneath the epineurium and between the perineurium. After 1 week of culture, more nerve cels proliferated and differentiated in the complete medium containing 200 mg/L tetramethylpyrazine or not, especialy in the complete medium containing 200 mg/L tetramethylpyrazine. Under the light microscope, the degree of lymphocyte infiltration ranged from more to less: nerve xenograft group, control group, experimental group, nerve alograft group. These findings indicate that tetramethylpyrazine can reduce tissue-engineered nerve immunogenicity, but cannot destroy the three-dimensional structure of tissue-engineered nerves.