Experimental study of the embryology in the ear

1. 组织学观察小鼠外耳、中耳发育正常。特别是在胚胎镫骨上明确了中耳的主要结构。研究了镫骨足的发育起源，证实其起源于足前庭表面的耳囊。出生后10、11天外耳鼓膜形成。维生素A致畸性及生物碱抑制作用的实验研究。在妊娠第10天，将母鼠分为4组，分别给予维生素A、维生素A和头孢烷素（一种生物碱）、头孢烷素和不给予对照。结果显示，用头孢蓝素治疗组由母体维生素A过多症引起的胎儿外部畸形发生率明显降低。进一步对同种材料进行骨软骨染色，观察其中耳区表现。从这些研究中可以看出，头孢蓝素对过量维生素A对外部和内部畸形的致畸活性的抑制作用与头孢蓝素的膜稳定作用有关。将妊娠第10天的小鼠胚胎耳区外植入器官培养系统，培养4 ~ 10 d。耳区组织培养4 ~ 5 d后，组织学标本显示内耳感觉上皮、软骨囊、声面神经节细胞、面神经纤维和听骨样块发育。用全胚培养技术研究大鼠耳部发育。采用全胚培养技术，于妊娠11.5天将大鼠胚胎外植，培养24小时。对培养胚和对照胚的耳区进行了形态学和组织学检查。对照组耳囊肿形态简单，呈卵圆形。培养胚耳囊变长变窄，内淋巴管清晰可见。少

1. Normal development of the ear The normal development of the external and middle ear in the mouse was observed histologically. Especially, main structures in the middle ear were clarified on the embryological stapes. The developmental origin of the stapes footplate was investigated and confirmed to be derived from the otic capsule in the vestibular surface of the footplate. On the external ear, formation of the tympanic membrane was observed at the 10 or 11 days after the birth.2. The experimental studies of teratogenicity of Vitamin A and the inhibitory effect of alkaloid on it.Mother rats were divided into 4 groups consisted of rats treated with Vitamin A, Vitamin A and Cepharanthin ( a kind of alkaloid), Cepharanthin and nothing as control at day 10 of pregnancy. In the results, the frequency of external malformations in fetuses induced by maternal hypervitaminosis A was remarkably decreased in the group treated with Cepharanthin. Further more, the same meterials were stained with … More bone and cartilage staining method and thefindings of their middle ear region were observed. From these studies, the inhibitory effect of Cepharanthin to the teratogenic activity of excessive Vitamin A on the external and internal malformations was suggested concerning with the membrane stabilizing effect of Cepharanthin.3. Embryological observations of the mouse ear using organ culture techniqueThe ear region in the 10th gestation day mouse embryo was explanted into the organ culture system and was cultured for 4 days to 10 days.The tissues of ear region cultured for 4 or 5 days showed the developing sensory epithelium in the inner ear, cartilaginous otic capsule, acoustico-facial ganglion cells, facial nerve fibers and anlage of ossicles in their histological specimens.4. Developmental study of the rat ear using whole embryo culture technique.Rat embryos were explanted at 11.5 days of gestation and cultured for 24 hours using the whole embryo culture technique.Morphological and histological examinations were made on the ear region of the cultured and control embryos. In the control group, otocysts were simple and oval in shape.In the cultured embryos, otocysts elongated and narrowed and endolymphatic ducts could clearly be seen. Less