Iliev M E, Van der Zypen E, Fankhauser F, England C
Institute of Anatomy, University of Bern, Switzerland.
Exp Eye Res. 1995 Sep;61(3):311-21. doi: 10.1016/s0014-4835(05)80126-5.
This study was undertaken to examine ultrastructurally the course of tissue regeneration after thermally-induced laser sclerostomy and compare it with the post-operative clinical events in a rabbit model. Applying a continuous wave neodymium:YAG (Nd:YAG) laser, two sclerostomies were created ab interno on one eye in each of ten pigmented rabbits using a 200-microns-diameter quartz optical fiber; the unoperated fellow-eyes served as controls. Intraocular pressure (IOP) was measured daily before and after surgery. Animals were observed post-operatively for up to 16 days. Well-defined filtering blebs and a low complication rate demonstrated the success of the procedure. IOP was significantly lowered during the entire course of the observation period but after the fifth day, the conjunctival blebs had disappeared. The morphology of the changes in the sclerostomy fistulas were analysed at 2-day intervals by light and electron microscopy. Immediately after surgery, the canal was ensheathed by an approximately 100-microns-thick layer of coagulated collagenous tissue in which two zones could be distinguished according to the intensity of damage. Within 5 days, the inner and outer canal openings were invaded by macrophages and fibroblasts originating from the iris root and episclera, respectively. The former cells were engaged in the phagocytosis of disintegrated collagen adjacent to the lumen. More distally located fibrils which had incurred less severe damage, had retained their fibrillar structure but had lost banding periodicity. After thermal stress had faded, they appeared to undergo a process of repolymerisation. By day 10, the lumen had become occluded by a loose meshwork of phagocytes, fibroblasts and proliferating capillaries. These new vessels and the loose nature of the canal-occluding framework and of the surrounding regenerating collagenous tissue could have further permitted percolation and transport of aqueous humor, since IOP remained low, despite the disappearance of filtering blebs. Although the time course of repair is more rapid in rabbits than in humans, the data gleaned nonetheless yield valid information respecting the sequence of events following thermally-induced scleral fistula.
本研究旨在通过超微结构观察热诱导激光巩膜造口术后组织再生过程，并将其与兔模型中的术后临床事件进行比较。使用连续波钕：钇铝石榴石（Nd:YAG）激光，通过200微米直径的石英光纤在10只有色兔的每只眼睛内进行两次巩膜造口术；未手术的对侧眼作为对照。在手术前后每天测量眼压（IOP）。术后观察动物长达16天。明确的滤过泡和低并发症发生率证明了该手术的成功。在整个观察期内眼压显著降低，但在第5天后，结膜滤过泡消失。每隔2天通过光学显微镜和电子显微镜分析巩膜造口瘘管变化的形态。手术后立即，巩膜管被一层约100微米厚的凝固胶原组织包绕，根据损伤程度可分为两个区域。在5天内，内、外巩膜管开口分别被来自虹膜根部和巩膜上组织的巨噬细胞和成纤维细胞侵入。前者细胞参与吞噬管腔内崩解的胶原。位于更远端、损伤较轻的纤维保留了其纤维结构，但失去了条带周期性。热应激消退后，它们似乎经历了再聚合过程。到第10天，管腔被吞噬细胞、成纤维细胞和增生的毛细血管组成的疏松网络阻塞。尽管滤过泡消失，但由于眼压仍然较低，这些新血管以及阻塞管腔的框架和周围再生胶原组织的疏松性质可能进一步允许房水的渗透和运输。虽然兔的修复时间进程比人类更快，但所收集的数据仍然提供了关于热诱导巩膜瘘管后事件顺序的有效信息。
