[论文解读] Absence of Typical Haversian System from the Compact Bone of Some Reptile and Bird Species

Yasser A. Ahmed, Mohamed Abdelsabourv Khalaf+1 more|arXiv (Cornell University)|Jul 24, 2017

Comparative Animal Anatomy Studies参考文献 15被引用 4

一句话总结

本研究通过组织学分析，调查了选定爬行类和鸟类物种中密集体骨内典型哈弗斯系统缺失的现象。研究发现，壁虎缺乏血管化结构，尼罗 monitor 蜕具有高血管化程度，而鸭子和大雁等鸟类则表现出可变的骨组织微结构，部分区域为致密哈弗斯组织，另一些区域则存在初级骨单位，表明哺乳动物的哈弗斯系统并非羊膜动物内骨骼的普遍特征。

ABSTRACT

Background and Objective: Mammalian compact bone is composed mostly of Haversian system. Although there are many studies describing the typical Haversian system in mammals, there are few studies conducted on bones from non-mammalian species. The objective of the current study was to investigate the existence of the typical Haversian system in compact bones from reptiles and birds. Materials and Methods: Femora were collected from geckos, Nile monitors, sparrows, ducks and geese. Samples were then, fixed in 10% paraformaldehyde and embedded in paraffin. Paraffin sections were stained with hematoxylin and eosin or Von Kossa and then examined using light microscopy. Results: The current study showed different histological structures of compact bones from studied species and an absence of the typical Haversian system seen in mammals. The compact bone of geckos was mostly avascular, while Nile monitor bone was highly vascular. Sparrow bone showed one side vascular and the other side avascular. The vascularity was represented by primary vascular canals surrounded by a few irregularly arranged osteocytes inside their lacunae forming primary osteons. Bone tissue from ducks and geese were similar and were composed mostly of dense Haversian tissue, while some areas had primary osteons. Conclusion: The compact bone microstructure in some reptile and bird species lack the typical Haversian system described in mammals. This will be of a great importance in developing a better understanding of long bone anatomy and physiology in different species.

研究动机与目标

• 调查非哺乳类物种密集体骨中是否存在典型哈弗斯系统。
• 将爬行类与鸟类的骨组织微结构与哺乳动物（其哈弗斯系统已有充分记录）进行比较。
• 理解非哺乳类羊膜动物骨结构变异的演化与功能意义。
• 为脊椎动物类群中长骨解剖学与生理学的更全面理解做出贡献。

提出的方法

• 采集壁虎、尼罗 monitor、麻雀、鸭子和大雁的股骨样本。
• 样本用10%多聚甲醛固定，并包埋于石蜡中以进行切片。
• 石蜡切片经苏木精-伊丽莎白红或冯·科萨染色，以可视化细胞结构与矿化基质。
• 使用光学显微镜观察组织学特征，包括血管化程度、骨细胞排列及骨单位形态。
• 将微结构模式分类为初级骨单位、致密哈弗斯组织或无血管密集体骨。
• 跨物种进行比较分析，以识别与哺乳动物哈弗斯系统一致的模式或偏离。

实验结果

研究问题

• RQ1 非哺乳类爬行类与鸟类是否表现出哺乳类密集体骨中典型的哈弗斯系统？
• RQ2 不同爬行类与鸟类物种的密集体骨微结构存在哪些组织学差异？
• RQ3 所研究物种股骨密集体骨中的血管化分布如何分布？
• RQ4 初级骨单位或类似哈弗斯的结构在多大程度上取代或模拟了哺乳动物的哈弗斯系统？
• RQ5 典型哈弗斯系统的缺失或存在对非哺乳类羊膜动物骨生理与演化意味着什么？

主要发现

• 壁虎股骨密集体骨主要为无血管结构，缺乏典型的哈弗斯系统。
• 尼罗 monitor 骨组织表现出高血管化，具有初级血管管道，且骨细胞排列不规则，形成初级骨单位。
• 麻雀股骨表现出单侧血管化，一侧为血管化结构，另一侧为无血管结构。
• 鸭与大雁的骨组织相似，主要由致密哈弗斯组织构成，但部分区域含有初级骨单位。
• 典型的哈弗斯系统（哺乳类骨组织的特征）在所研究的爬行类与鸟类密集体骨中均未出现。
• 各物种间微结构的多样性表明，哺乳动物的哈弗斯系统并非羊膜动物内骨骼的普遍特征。