Study for speciality of mechanism of biological response in developing retina and vitreous

我们在比格犬幼犬出生后4天，在95% ~ 100%的氧气环境下，发生了氧致视网膜病变。约50%的幼犬出现玻璃体视网膜疾病。电病理组织学上观察到细胞变形虫过程、丰富的糖原颗粒、低分化的基底膜，这些都是视网膜新生血管的常见表现。然而，这种细胞萌芽现象不仅发生在周围视网膜，也发生在中央视网膜。外围出芽与中心出芽形态差异不显著。新生血管周围可见大量巨噬细胞和胶原原纤维。巨噬细胞内溶酶体颗粒丰富，细胞核偏位。胶原纤维非常粗大，显示65nm的周期带，与正常玻璃体胶原有很大不同，认为是I型胶原。因此，这些巨噬细胞似乎不是进行新生血管形成，而是吞噬异物。有的品种不仅视网膜血管增生，而且玻璃体血管增生。其中4例沿透明体系统形成视网膜褶皱。电镜下，视网膜皱襞与增生的玻璃体血管和胶原纤维紧密粘连。部分新生血管周围细胞肌动蛋白免疫组化阳性，提示存在肌成纤维细胞。因此，视网膜褶皱和/或视网膜拖拽可能是由成纤维细胞附着和肌成纤维细胞主动收缩形成的。这一发现不仅对研究ROP，而且对研究伴有增殖性玻璃体视网膜病变的先天性视网膜折叠具有重要意义。

We developed oxygen induced retinopathy in beagle puppy with 95%-100% oxygen exposure for 4 days after birth. About 50% puppies showed vitreoretinal disorders. Electropathohistologically, cellular amoeboid process, rich glycogen granules, and poorly differentiated basement membrane, were observed, which were common findings of noevascularization of human retina. However, such cellular budding phenomenon was observed not only in peripheral but central retina. And no significant morphological deference was recognized between peripheral budding and central one.Around neovascularization, many macrophages and collagen fibrils were detected. Rich lysosome granules and deviation of nucleus were observed in macrophages. Collagen fibers, which was quite different from normal vitreous collagen were very bold and showed 65nm period's band which thought to be the type I collagen. Therefore these macrophages seemed to not conduct the neovascularization but to phagocytize foreign bodies.Some species showed not only retinal vasculature but hyaloid vasculature had been proliferated. Four of them formed retinal folds along hyaloid system.Electron-microscopically, retinal folds adhered tightly with proliferated hyaloid vessels and collagen fibers. Some cells, surrounded neovascularization, showed positive in actin immunohistochemically which suggested to exist myofibroblasts. Therefore retinal fold and/or dragged retina may be formed by attachment of fibroblasts and active shrinkage of myofibroblasts.This finding was very interesting and very important to investigate not only ROP but congenital retinal folds with proliferative vitreoretinal changes of developing stages.