Takabatake K, Yamamoto T
Department of Anatomy, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Anat Embryol (Berl). 1991;183(6):537-44. doi: 10.1007/BF00187902.
The prenatal and postnatal development of the mouse knee joint was investigated by transmission and scanning electron microscopy. In the prenatal stage, following the appearance of a narrow intercellular cleft between two skeletal elements on the 16th fetal day, clefting extended into the lateral synovial mesenchyme. In some regions, the extension of the cleft was very rapid, but in a certain region (future fat pad region), it was somewhat slower. Macrophage-like cells appeared in the synovial mesenchyme on the 16th fetal day, and then increased in number, and were distributed as if they were clustering around the presumptive clefting zone in the future fat pad region on the 17th-18th fetal day. This suggests that macrophage-like cells may participate in joint development, as they phagocytize and remove some kinds of solid extracellular matrix, and facilitate the cleft extension. In the early postnatal stage, scanning electron microscopic observations showed that there were two different types of cell in the synovial lining. One of them exhibited a surface morphology corresponding to that of macrophages: a spherical cell body and numerous pseudopodia. The other type of cell exhibited various cell shapes with many cytoplasmic processes extending along the synovial surface.
通过透射电子显微镜和扫描电子显微镜研究了小鼠膝关节的产前和产后发育。在产前阶段，在胎儿第16天时，两个骨骼元件之间出现狭窄的细胞间裂隙后，裂隙延伸至外侧滑膜间充质。在某些区域，裂隙的延伸非常迅速，但在某个区域（未来的脂肪垫区域），其延伸速度稍慢。巨噬细胞样细胞在胎儿第16天时出现在滑膜间充质中，然后数量增加，并在胎儿第17 - 18天时分布在未来脂肪垫区域，就好像它们聚集在假定的裂隙形成区域周围。这表明巨噬细胞样细胞可能参与关节发育，因为它们吞噬并清除某些种类的固体细胞外基质，并促进裂隙延伸。在出生后早期，扫描电子显微镜观察显示滑膜衬里有两种不同类型的细胞。其中一种细胞的表面形态与巨噬细胞的表面形态相对应：球形细胞体和许多伪足。另一种类型的细胞呈现出各种细胞形状，有许多细胞质突起沿着滑膜表面延伸。
