目的采用光镜放射自显影(Light microscopic autoradiography, LM-ARG)及电镜放射自显影(Electron microscopic autoradiography, EM-ARG)技术，观察小鸡再生听毛细胞及其突触连接的特征。方法 7d龄纯种伊莎鸡20只，实验组(n=14)，连续皮下注射庆大霉素10d；对照组(n=6)。皮下注射生理盐水，用药第4d开始注射氚标记胸腺嘧啶核苷，分别于停药当天及第7d取标本作LM-ARG和EM-ARG。结果停药当天组光镜下标记细胞多为支持细胞，位于损伤区基底膜上至表层之间；电镜下有标记的毛细胞位于腔面，银颗粒呈卷丝状，准确定位于细胞核上，毛细胞下可见尚未成熟的神经突触，内含较多囊泡及线粒体，突触特殊结构尚不明显。停药第7d时光镜发现受损区有标记的成熟毛细胞；电镜下再生毛细胞及突触特征与当天组相似。对照组未见标记的毛细胞和支持细胞。结论：庆大霉素中毒后鸡基底乳头中细胞增殖活跃，基底乳头中某些支持细胞作为前体细胞，通过有丝分裂增殖分化为毛细胞。再生毛细胞及其突触结构尚待进一步发育成熟。本结论为毛细胞再生及其神经突触的恢复提供了直接依据。%Objective To observe regenerated hair cells and new neural synapses in the chicken cochlea by the use of autoradiography. Methods Seven-day old chicks were given gentamicin or distilled water for 10 days. All birds were also injected with 3H-Thymidine (3H-TdR) begining on the fourth day of the period. Following postinjection survival periods of the same or 7 days, the basilar papilla was processed for light microscopic autoradiography (LM-ARG) and electron microscopic autoradiography (EM-ARG). Results Incorporation of 3H-TdR was seen over hair cells and supporting cells in the experimental papilla in regions hair cell loss. In EM-ARG, the silver grains had a simple structure, usually consisting of a single filment. It was localized on the neuclei of regenerated hair cells. Neural synapses were found at the end of the new hair cells. The synapses contained many mitochondrions and vesicles. They looked like efferent synapses. Conclusion These results showed a potential capability of cellular proliferation in damaged auditory epithelia. Some of the supporting cells in the damaged region could be precusors for regenerating hair cells. The restoration of hair cell numbers following gentamicin toxicity result from the production of new cells by mitosis. The present results provide a direct evidence of innervation to hair cells after regeneration.
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