Department of Anatomy and Embryology, School of Basic Medical Sciences, Peking University, Beijing, China.
Invest Ophthalmol Vis Sci. 2013 Jun 12;54(6):4092-101. doi: 10.1167/iovs.13-12004.
The antioxidant response element (ARE)-mediated antioxidant pathway has an important role in maintaining the redox status of the retina. The expression of ARE-mediated antioxidants, such as heme oxygenase-1 (HO-1), remains unclear in the db/db mice. We evaluated the expression of HO-1 in the retinas of db/db mice and investigated a possible role for NADPH oxidase.
Fresh retinas were harvested from 8-, 12-, and 20-week db/db or db/m mice. Reactive oxygen species were detected by dihydroethidium. The expression levels of HO-1, Nox2, and Nox4 were evaluated by immunohistochemistry and Western blotting. In vitro retina explants culture was used to assess the role of NADPH oxidase in high glucose-induced HO-1 expression.
The expression of HO-1 was increased in the retinas of 8-week db/db mice, while it was decreased in 20-week db/db mice compared to age-matched controls. Similarly, the activation of Nox4 was increased in the retinas at 8 weeks and returned to basal levels at 20 weeks in db/db mice compared to age-matched controls. The activation of Nox2 was increased in the retinas of 8-, 12-, and 20-week db/db mice compared to age-matched controls. The NADPH oxidase inhibitors apocynin and DPI significantly blocked the HO-1 expression that was induced by high glucose levels in cultured retina explants.
The expression patterns of HO-1, Nox2, Nox4 in db/db mouse retinas, and the suppressive effects of NADPH oxidase inhibitors on the expression of HO-1 induced by high glucose levels in cultured retina explants suggest that the expression of HO-1 is, at least partially, mediated by NADPH oxidase in this diabetic animal model.
抗氧化反应元件（ARE）介导的抗氧化途径在维持视网膜氧化还原状态方面具有重要作用。血红素加氧酶-1（HO-1）等 ARE 介导的抗氧化剂的表达在 db/db 小鼠中的表达尚不清楚。我们评估了 db/db 小鼠视网膜中 HO-1 的表达，并研究了 NADPH 氧化酶的可能作用。
从 8 周、12 周和 20 周龄 db/db 或 db/m 小鼠中采集新鲜视网膜。通过二氢乙啶检测活性氧。通过免疫组织化学和 Western blot 评估 HO-1、Nox2 和 Nox4 的表达水平。体外视网膜外植体培养用于评估 NADPH 氧化酶在高糖诱导的 HO-1 表达中的作用。
与年龄匹配的对照组相比，8 周龄 db/db 小鼠视网膜中 HO-1 的表达增加，而 20 周龄 db/db 小鼠中 HO-1 的表达减少。同样，与年龄匹配的对照组相比，8 周 db/db 小鼠视网膜中 Nox4 的激活增加，而 20 周 db/db 小鼠中 Nox4 的激活恢复到基础水平。与年龄匹配的对照组相比，8 周、12 周和 20 周龄 db/db 小鼠视网膜中 Nox2 的激活增加。NADPH 氧化酶抑制剂 apocynin 和 DPI 可显著阻断高糖诱导的体外培养视网膜外植体中 HO-1 的表达。
db/db 小鼠视网膜中 HO-1、Nox2、Nox4 的表达模式以及 NADPH 氧化酶抑制剂对高糖诱导的体外培养视网膜外植体中 HO-1 表达的抑制作用表明，在这种糖尿病动物模型中，HO-1 的表达至少部分是由 NADPH 氧化酶介导的。
