Hesse L, Nebeling B, Schroeder B, Heller G, Kroll P
Department of Ophthalmology, Philipps-University, Marburg, FRG, Germany.
Exp Eye Res. 2000 Jan;70(1):31-9. doi: 10.1006/exer.1999.0772.
The purpose of this study was to generate intravitreal plasmin after intravitreal injection of tissue plasminogen activator (TPA) and cryopexy, and to assess its proteolytic effect on the vitreoretinal border region.Twenty-four hr after a mild cryopexy, 25 microg recombinant tissue plasminogen activator (TPA) was injected into the vitreous cavity, the fellow eye received an intravitreal injection of the same volume of buffered salt solution. Light, scanning and transmission electron microscopy was performed in 24 eyes that underwent vitrectomy 1 week later. Plasmin was measured prior and 2 hr after intravitreal TPA injection (4 eyes). Hyaluronic acid (8 eyes) and vitronectin (4 eyes) were measured 1 week after TPA- or BSS-injection and compared to untreated controls. In all eyes treated with TPA, histopathologic examination by scanning and transmission electron microscopy demonstrated a complete detachment of the vitreous from the surface of the retina as well as from the posterior surface of the lens. After BSS-injection, vitreous cortex attachment to the retina was demonstrated in all eyes. Two hr after TPA-injection, plasmin increased to 9.75 mU ml(-1)(s.d.+/-2.3). Neither a decrease of hyaluronic acid nor an increase of transglutaminase, that might alter the vitreous structure leading to a collapse of the vitreous, were detected in treated eyes. There was no increase of vitronectin indicating proliferative activity.A temporary breakdown of the blood-retinal barrier by cryopexy combined with intravitreal injection of TPA is a sufficient technique to induce a posterior vitreous detachment enzymatically. The method may be useful prior to mechanical vitrectomy.
本研究的目的是在玻璃体内注射组织型纤溶酶原激活剂（TPA）并进行冷冻治疗后产生玻璃体内纤溶酶，并评估其对玻璃体视网膜边界区域的蛋白水解作用。在轻度冷冻治疗24小时后，将25微克重组组织型纤溶酶原激活剂（TPA）注入玻璃体腔，对侧眼玻璃体内注射相同体积的缓冲盐溶液。1周后对24只接受玻璃体切除术的眼睛进行光镜、扫描电镜和透射电镜检查。在玻璃体内注射TPA前及注射后2小时测量纤溶酶（4只眼）。在TPA或平衡盐溶液（BSS）注射1周后测量透明质酸（8只眼）和玻连蛋白（4只眼），并与未治疗的对照组进行比较。在所有接受TPA治疗的眼中，扫描电镜和透射电镜的组织病理学检查显示玻璃体与视网膜表面以及晶状体后表面完全分离。注射BSS后，所有眼中均显示玻璃体皮质与视网膜相连。注射TPA后2小时，纤溶酶增加至9.75 mU ml⁻¹（标准差±2.3）。在治疗的眼中未检测到透明质酸减少或转谷氨酰胺酶增加，而转谷氨酰胺酶增加可能会改变玻璃体结构导致玻璃体塌陷。未发现玻连蛋白增加表明有增殖活性。冷冻治疗联合玻璃体内注射TPA导致血视网膜屏障暂时破坏是一种通过酶促诱导玻璃体后脱离的充分技术。该方法在机械性玻璃体切除术之前可能有用。
