Liu Quan, Ju Won-Kyu, Crowston Jonathan G, Xie Fang, Perry George, Smith Mark A, Lindsey James D, Weinreb Robert N
Hamilton Glaucoma Center and the Department of Ophthalmology, University of California San Diego, La Jolla, California 92037-0946, USA.
Invest Ophthalmol Vis Sci. 2007 Oct;48(10):4580-9. doi: 10.1167/iovs.07-0170.
To determine whether oxidative adduct formation or heme oxygenase-1 (HO-1) expression are altered in retinal ganglion cell (RGC) cultures exposed to elevated hydrostatic pressure and in a mouse model of glaucoma.
Cultured RGC-5 cells were subjected to 0, 30, 60, or 100 mm Hg hydrostatic pressure for 2 hours, and the cells were harvested. Parallel experiments examined the recovery from this stress, the effect of direct 4-hydroxy-2-nonenal (HNE) treatment, and the effect of pretreatment with resveratrol or quercetin. Mice were anesthetized and intraocular pressure was increased to 30, 60, or 100 mm Hg for 1 hour; then the retinas were harvested. HNE adduct formation and HO-1 expression were assessed by immunocytochemistry and immunoblotting.
Increases of HNE-protein adducts (up to 5-fold) and HO-1 expression (up to 2.5 fold) in pressure-treated RGC-5 cells were dose dependent. During recovery experiments, HNE-protein adducts continued to increase for up to 10 hours; in contrast, HO-1 expression decreased immediately. HNE, at a concentration as low as 5 muM, led to neurotoxicity in RGC-5 cells. HNE adducts and HO-1 expression increased in the mouse retina and optic nerve after acute IOP elevation up to 5.5-fold and 2-fold, respectively. Antioxidant treatment reduced the oxidative stress level in pressure-treated RGC-5 cells.
This study demonstrates that oxidative stress is an early event in hydrostatic pressure/IOP-induced neuronal damage. These findings support the view that oxidative damage contributes early to glaucomatous optic neuropathy.
确定在暴露于升高的静水压力的视网膜神经节细胞（RGC）培养物以及青光眼小鼠模型中，氧化加合物的形成或血红素加氧酶-1（HO-1）的表达是否发生改变。
将培养的RGC-5细胞置于0、30、60或100 mmHg的静水压力下2小时，然后收获细胞。平行实验检测了这种应激后的恢复情况、直接4-羟基-2-壬烯醛（HNE）处理的效果以及白藜芦醇或槲皮素预处理的效果。对小鼠进行麻醉，并将眼压升高至30、60或100 mmHg持续1小时；然后收获视网膜。通过免疫细胞化学和免疫印迹评估HNE加合物的形成和HO-1的表达。
压力处理的RGC-5细胞中HNE-蛋白质加合物的增加（高达5倍）和HO-1表达的增加（高达2.5倍）呈剂量依赖性。在恢复实验中，HNE-蛋白质加合物持续增加长达10小时；相比之下，HO-1表达立即下降。低至5 μM的HNE浓度即可导致RGC-5细胞发生神经毒性。急性眼压升高后，小鼠视网膜和视神经中的HNE加合物和HO-1表达分别增加至5.5倍和2倍。抗氧化剂处理降低了压力处理的RGC-5细胞中的氧化应激水平。
本研究表明氧化应激是静水压力/眼压诱导的神经元损伤中的早期事件。这些发现支持氧化损伤在青光眼性视神经病变早期起作用的观点。
