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

我们用95%-100%的氧暴露于出生后4天的比格幼犬发生了氧诱导的视网膜病变。约50%的幼犬出现玻璃体视网膜病变。电镜下可见细胞变形虫样突起、丰富的糖原颗粒和低分化的基底膜，这是视网膜新生血管化的常见表现。然而，这种细胞出芽现象不仅在周边而且在中央视网膜中观察到。周围出芽与中央出芽形态无明显差异，新生血管周围可见大量巨噬细胞和胶原纤维。巨噬细胞内可见丰富的溶酶体颗粒，细胞核偏向一侧。与正常玻璃体胶原不同的是，玻璃体内胶原纤维粗大，呈65 nm的周期带，为Ⅰ型胶原。因此，这些巨噬细胞似乎并不引导新生血管的形成，而是吞噬异物。其中4例沿玻璃体系统形成沿着的视网膜皱褶，电镜下视网膜皱褶与增生的玻璃体血管和胶原纤维紧密粘连。部分新生血管周围的细胞肌动蛋白染色呈阳性，提示存在肌成纤维细胞。这一发现不仅对ROP的研究，而且对发育阶段伴有增生性玻璃体视网膜改变的先天性视网膜皱褶的研究都是非常有趣和重要的。

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.