Truter J Christoff, Myburgh Jan G
Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
Int J Dev Biol. 2021;65(10-11-12):551-556. doi: 10.1387/ijdb.210196ct.
Crocodilians exhibit continuous tooth replacement (i.e., polyphyodonty) and have been identified as suitable models for tooth regeneration research due to the similarity in dental cavity and tooth anatomy between these creatures and humans. Various studies reporting bird embryo manipulation exist, but such reports for reptiles are virtually non-existent. Egg windowing enables direct access to oviparous vertebrate embryos and is therefore an important component of embryo manipulation experiments. The aim of the present study was to window Nile crocodile, eggs and assess the potential of direct manipulations, targeting the pharyngeal region where the maxilla and mandible originates. eggs were successfully windowed, and a limited number of individuals survived the entire gestation period. The 1st trimester of gestation was the most sensitive, and 96.78% of the mortalities occurred within this period. Our data indicate the suitable window for embryo manipulation targeting the mandibular arch and maxillary process, without a risk of damaging the chorioallantoic membrane (CAM) (which may be fatal), was between day six and eight after laying for embryos incubated at 31°C. This data will be of use for future embryo-based experiments related to jaw and tooth development in crocodiles as well as human tooth regeneration research.
鳄鱼表现出持续的牙齿替换（即多牙列），并且由于这些生物与人类在牙腔和牙齿解剖结构上的相似性，已被确定为牙齿再生研究的合适模型。有各种关于鸟类胚胎操作的研究报告，但关于爬行动物的此类报告几乎不存在。卵开窗能够直接接触卵生脊椎动物胚胎，因此是胚胎操作实验的重要组成部分。本研究的目的是对尼罗鳄卵进行开窗，并评估针对上颌骨和下颌骨起源的咽部区域进行直接操作的可能性。卵成功开窗，并且有少数个体在整个妊娠期存活下来。妊娠的头三个月最为敏感，96.78%的死亡发生在此期间。我们的数据表明，对于在31°C下孵化的胚胎，在产卵后第六天至第八天之间是针对下颌弓和上颌突进行胚胎操作的合适窗口，而不会有损坏尿囊绒膜（CAM）（这可能是致命的）的风险。这些数据将用于未来与鳄鱼颌骨和牙齿发育以及人类牙齿再生研究相关的基于胚胎的实验。
