牦牛角的形态发生及Shh和β-catenin的时空表达

Temporal-Spatial Expression of Shh and β-catenin during Horn Morphogenesis in Yak

研究对象为Ed（Embryonic days）60-240,0.5-5岁公牦牛角（原）基。采用石蜡切片、HE染色和免疫组化的方法研究牦牛角的形态发生过程,检测Shh（Sonic hedgehog）和β-catenin的时空表达与互作规律。结果表明,牦牛角的形态发生按照角（原）基毛囊和角质外鞘发生与否分为5个阶段：角原基前期（Ed≤60）表皮增厚,无毛囊发生;角原基中期（Ed60-140）表皮持续增厚,有少量毛囊发生;角原基后期（Ed140-250）表皮变薄,大量毛囊发生;肉角期（≤0.5 a）真皮乳头发生;成角期（≥0.5 a）形成角质外鞘。角原基期的顶部和角边缘处基底层Shh与β-catenin表达趋势相同,均为强-弱-强过程;肉角期的角边缘处基底层Shh与β-catenin同时表达,顶部仅β-catenin表达;成角期的角边缘处基底层Shh与β-catenin同时表达,顶部均无表达。结果提示：Shh在牦牛角的形态发生中负责表皮基底层形态分化,β-catenin则起着维持细胞分化状态并促进细胞增殖的作用。

Ed60-240 Yak embryos horny placode and 0.5-5 a adult horn were used as material. Yak horny morphogenesis was investigated by H. E stain and immunohistochemistry of tissue section for detecting temprocal-spatial expression during morphogenesis and their reciprocal interaction. Result showed that the epidermis dominant the morphogenesis changes. Mesenchymal is subdominant . β- catenin expression begin from horny placode epidermis stage and go up increasingly to peak value and maintain in hair follicle. The range of mesenchymal change is less. Shh expression transform dramaticly to stimulate the horny placode-adult horn. Shh and β-catenin act cooperate interaction and special function each other. Shh is responsible for directing differentiation and determining cell fate , β-catenin charge in proliferation during cell differentiation . Our results imply Shh and β-catenin expression and detail function may play a key role in regulating horn morphogenesis.