Cellular and Vascular Changes in the Retina of Neonatal Rats after an Acute Exposure to Hypoxia
Cellular and Vascular Changes in the Retina of Neonatal Rats after an Acute Exposure to Hypoxia
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DOI：
10.1167/iovs.09-3552
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发表时间：
2009-11-01
影响因子：
4.4
通讯作者：
Ling, Eng-Ang
中科院分区：
文献类型：
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作者：
Kaur, Charanjit;Sivakumar, Viswanathan;Ling, Eng-Ang
目的.本研究旨在探讨急性低氧暴露对视网膜细胞和血管因子如血管内皮生长因子（VEGF）和一氧化氮（NO）产生的影响，这些血管因子可能影响发育中视网膜的血管通透性。在低氧暴露后3小时至14天，检查1日龄大鼠的视网膜。采用实时荧光定量PCR、免疫印迹和免疫组化方法检测缺氧诱导因子-1 α（HIF-1 alpha）、VEGF、内皮型一氧化氮合酶（eNOS）、神经型一氧化氮合酶（nNOS）和诱导型一氧化氮合酶（iNOS）的mRNA和蛋白表达。用电子显微镜检查视网膜细胞的结构改变，并通过腹膜内或静脉内注射罗丹明异硫氰酸酯（RhIC）或辣根过氧化物酶（HRP）来测定血管通透性。缺氧后，HIF-1 α、VEGF、eNOS、nNOS和iNOS的mRNA和蛋白表达沿着VEGF浓度和NO生成均增加。结果表明，缺氧动物的神经节细胞出现线粒体肿胀、断裂等变化，神经节细胞内核层细胞凋亡、坏死。缺氧后视网膜和玻璃体血管的RhIC和HRP渗漏增加。作者认为，缺氧时VEGF和NO的产生增加导致血管通透性增加，导致Muller细胞的变化和神经细胞的变性。褪黑激素的管理减少VEGF和NO的生产，减少泄漏的RhIC和HRP，并促进细胞增殖，这表明这是一个潜在的治疗剂，在减少缺氧相关的损害，在发展中的视网膜。（Invest Ophthalmol维斯科学。2009;50：5364-5374）DOI：10.1167/iovs.09-3552
PURPOSE. This study was undertaken to examine the effects of an acute hypoxic exposure on the retinal cells and production of vascular factors such as vascular endothelial growth factor (VEGF) and nitric oxide (NO), which may affect vascular permeability in the developing retina.METHODS. Retinas of 1-day-old rats were examined at 3 hours to 14 days after hypoxic exposure. The mRNA and protein expression of hypoxia-inducible factor-1 alpha (HIF-1 alpha), VEGF, endothelial nitric oxide synthase (eNOS), neuronal NOS (nNOS), and inducible NOS (iNOS) were determined by real-time RTPCR, Western blot analysis, and immunohistochemistry. Electron microscopy was used to examine the structural alterations in retinal cells, and rhodamine isothiocyanate (RhIC) or horseradish peroxidase (HRP) was administered intraperitoneally or intravenously to determine vascular permeability.RESULTS. The mRNA and protein expression of HIF-1 alpha, VEGF, eNOS, nNOS, and iNOS, along with VEGF concentration and NO production, were increased in response to hypoxia. Swollen Muller cell processes, apoptotic and necrotic cells in the inner nuclear layer, and changes in ganglion cells such as swollen and disrupted mitochondria were observed in hypoxic animals. Increased leakage of RhIC and HRP from retinal and hyaloid vessels was seen after hypoxic exposure.CONCLUSIONS. The authors suggest that increased VEGF and NO production in hypoxia resulted in increased vascular permeability, leading to changes in Muller cells and degeneration of neural cells. Melatonin administration reduced VEGF and NO production, diminished leakage of RhIC and HRP, and promoted cell proliferation, suggesting this as a potential therapeutic agent in reducing hypoxia-associated damage in the developing retina. (Invest Ophthalmol Vis Sci. 2009;50:5364-5374) DOI:10.1167/iovs.09-3552