Doheny Eye Institute, Los Angeles, CA, USA.
Int J Mol Med. 2011 Oct;28(4):505-11. doi: 10.3892/ijmm.2011.708. Epub 2011 May 23.
We recently demonstrated that αA-crystallin, a molecular chaperone, protected photoreceptors from apoptotic signals in intraocular inflammation. Advanced glycation end product (AGE) plays an important role in the progression of diabetic retinopathy. The aim of this study was to examine the expression of α-crystallins and apoptosis in human diabetic retina, and to analyze α-crystallin up-regulation in murine eyes after AGE stimulation. Eight eye globes were obtained from postmortem donors. Six out of the eight had a medical history of diabetes mellitus, while two were without diabetes. Formalin-fixed, paraffin-embedded tissue sections were subjected to H&E staining and immunohistochemistry with anti-αA and αB-crystallins, anti-AGE and receptor for AGE (RAGE) antibodies. Apoptotic cells were detected by the TUNEL assay. Recombinant AGE protein was injected into the vitreous of adult murine eyes, and the posterior eyecups were excised 4 days after the administration. Western blot analyses and quantitative real-time PCR were performed to evaluate the alteration of α-crystallin expression. Histopathology revealed no remarkable differences between diabetic and non-diabetic retinas. Immunoreactivity for αA-crystallin was predominantly detected in the diabetic retina, whereas αB-crystallin expression was relatively low. AGE immunoreactivity was highly detected in diabetic retina and the vitreous, whilst immunoreactivity for RAGE was less marked. TUNEL-positive apoptotic cells were occasionally observed in photoreceptors of the diabetic retina, whereas cytoplasmic immunoreactivity for αA-crystallin was relatively low. αA-crystallin expression was up-regulated, and αB-crystallin was down-regulated in murine posterior eyecups exposed to AGE protein. The mRNA levels of αA-crystallin were significantly up-regulated, whereas those of αB-crystallin remained unchanged after AGE stimulation. Thus, αA-crystallin and AGE were highly expressed in human diabetic retina. αA-crystallin responded to AGE accumulation, which may contribute to the protection of photoreceptors against AGE-related retinal tissue injury.
我们最近证明，分子伴侣αA-晶体蛋白可保护光感受器免受眼内炎症中的凋亡信号的影响。晚期糖基化终产物 (AGE) 在糖尿病性视网膜病变的进展中起重要作用。本研究的目的是检查人糖尿病性视网膜中α-晶体蛋白的表达和凋亡，并分析 AGE 刺激后鼠眼α-晶体蛋白的上调。从尸检供体中获得了 8 个眼球。其中 6 个有糖尿病病史，而 2 个没有糖尿病。用福尔马林固定、石蜡包埋的组织切片进行 H&E 染色和抗αA 和αB-晶体蛋白、抗 AGE 和 AGE 受体 (RAGE) 抗体的免疫组织化学染色。通过 TUNEL 测定检测凋亡细胞。将重组 AGE 蛋白注入成年鼠眼的玻璃体中，给药后 4 天切除后眼球。进行 Western blot 分析和定量实时 PCR 以评估α-晶体蛋白表达的变化。组织病理学检查显示糖尿病和非糖尿病视网膜之间无显着差异。αA-晶体蛋白的免疫反应性主要在糖尿病视网膜中检测到，而αB-晶体蛋白的表达相对较低。AGE 免疫反应性在糖尿病视网膜和玻璃体中高度检测到，而 RAGE 免疫反应性不明显。偶尔在糖尿病视网膜的光感受器中观察到 TUNEL 阳性凋亡细胞，而αA-晶体蛋白的细胞质免疫反应性相对较低。暴露于 AGE 蛋白的鼠后眼球中αA-晶体蛋白上调，而αB-晶体蛋白下调。αA-晶体蛋白的 mRNA 水平显着上调，而 AGE 刺激后αB-晶体蛋白的 mRNA 水平保持不变。因此，αA-晶体蛋白和 AGE 在人糖尿病性视网膜中高度表达。αA-晶体蛋白对 AGE 积累有反应，这可能有助于保护光感受器免受 AGE 相关的视网膜组织损伤。
