鼠诱发性高眼压和细胞凋亡的实验研究

目的 探讨鼠实验性急慢性高眼压的视网膜组织损伤机制。方法 应用前房内连续灌注生理盐水的方法制成急性高眼压鼠模型。实验后第1、2、4、5、7和10d观察视网膜反应。巩膜表浅静脉烧灼法制成慢性高眼压模型，分别于实验后1和2个月观察视网膜损害情况。用TUNEL技术和半胱胺酸天冬胺酸酶免疫组化研究法以证实视网膜细胞的凋亡机制，NADPH辅酶反应识别一氧化氮诱导的细胞。结果 急性高眼压模型的免疫组化研究证实节细胞凋亡是早期的细胞死亡，而在对照组一氧化氮合成酶在视网膜组织并不表现明显的活性。慢性高眼压模型实验提示一氧化氮合成酶活性增加，表明一氧化氮具有神经保护作用而并非仅存有细胞毒性作用。TUNEL和半胱胺酸天冬胺酸酶研究表明，凋亡开始于慢性高眼压的不同阶段。结论 了解高眼压所致的视网膜损害的机制为研究在细胞变性过程中某些物质对凋亡、一氧化氮合成酶和突触传递的影响，尤其是对研究青光眼节细胞死亡的机制提供了基础。

Action of induced hypertension and apoptosis: an experimental study in rat

Objective To study the retinal tissue degeneration of intraocular hypertension experimentally induced in acute and chronic way. Methods In the acute model, pressure elevation was quickly induced by a needle in the anterior chamber and the retinal reaction was studied at 1,2,4,5,7,10 days after treatment. The tissue damage with chronic hypertension,induced by the cauterization of two episcleral veins,was studied at 1 and 2 month after the treatment. The TUNEL method and Caspade 3a immunochemical study evidenced the apoptosis mechanism. The NADPH-diaphorase reaction identified the Nitric Oxide, ( NO) producing cells. Results In the acute model,the immunohistochemical study evidenced that the apoptosis was an early death mechanism for ganglionar cells. The activity of Nitric Oxide Synthase ( NOS) didn' t show a significant activation toward the retinal tissue of control. The chronic hypertension model indicated an increase in the NOS signal, meaning an activation of this enzyme in particular bear the vascular vessels, showing the neuroprotective and not only cytotoxic effect of the NO. The TUNEL and Caspase 3a studies indicated that the apoptosic mechanism started in different times, the immunohistochemical reaction showed its immediately beginning or its later activation caused by the chronic damage. Conclusions The opportunity to have a clear vision of the beginning and causing factors of cell degeneration in hypertension damage could permit the study on different substances that act on apoptosis , on NOS mechanism and on synaptic transmission inhibiting or deviating the retinal tissue degeneration and particularly the ganglionar cells death in glaucoma.