Ito M, Yoshioka M
Department of Anatomy, National Defense Medical College, 3-2 Namiki, Tokorozawa, 359-8513, Japan.
Anat Embryol (Berl). 1999 Oct;200(4):403-11. doi: 10.1007/s004290050289.
Regression of the pupillary membrane (PM) and hyaloid vessels - hyaloid arteries (HAs), tunica vasculosa lentis (TVL), and vasa hyaloidea propria (VHP) - in mice aged from 0 to 16 days was observed using stereomicroscopy and transmission electron microscopy. Whole-mount stereomicroscopy revealed that the pattern of normal developed vessels was basically the same as that reported in rats and rabbits and that the VHP and PM disappeared between 12 and 16 days and 10 and 12 days, respectively, while certain examples of the TVL and HA remained even at 16 days. In the TVL, VHP and PM, regression occurred segmentally and resulted in a decreased number of interconnections. The ultrastructure of the vessels in the VHP, TVL and PM was consistent with a typical capillary with pericyte covering and no fenestrations. HAs had tunica media and adventitia in the older stages. Some endothelial cells in the TVL and PM attaching to the lens capsule were thin at the side of the lens. Many macrophages were observed in the vitreous and around vessels in the whole-mount specimens at all stages. Some macrophages remained linearly arranged even after vessels became vestigial and disappeared. In transmission electron microscopy, most of these macrophages were seen to possess vacuoles and/or processes, and some of them had phagosomes. Electron microscopic findings from regressing ocular vessels were consistent with the apoptosis of both endothelia and pericytes. Obstruction of the vessels was noted at older stages. These results add further anatomical information to previous studies and suggest that the VHP and TVL as well as PM regress via apoptosis. The precise mechanisms of regression of hyaloid vessels and the role of macrophages remain for further studies.
利用体视显微镜和透射电子显微镜观察了0至16日龄小鼠瞳孔膜（PM）和玻璃体血管（包括玻璃体动脉（HA）、晶状体血管膜（TVL）和晶状体固有血管（VHP））的退化情况。整体标本体视显微镜检查显示，正常发育血管的模式与大鼠和兔子报道的基本相同，VHP和PM分别在12至16天和10至12天消失，而即使在16天时，TVL和HA仍有部分留存。在TVL、VHP和PM中，退化呈节段性发生，导致相互连接的数量减少。VHP、TVL和PM中血管的超微结构与典型的有周细胞覆盖且无窗孔的毛细血管一致。HA在较后期有中膜和外膜。TVL和PM中附着于晶状体囊的一些内皮细胞在晶状体一侧较薄。在所有阶段的整体标本中，玻璃体和血管周围均观察到许多巨噬细胞。即使血管退化并消失后，一些巨噬细胞仍呈线性排列。在透射电子显微镜下，这些巨噬细胞大多可见有液泡和/或突起，部分还有吞噬体。退化眼部血管的电子显微镜检查结果与内皮细胞和周细胞的凋亡一致。在较后期注意到血管阻塞。这些结果为先前的研究增添了更多解剖学信息，并表明VHP、TVL以及PM通过凋亡退化。玻璃体血管退化的确切机制以及巨噬细胞的作用仍有待进一步研究。
