Hayashi A, Koroma B M, Imai K, de Juan E
Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
Invest Ophthalmol Vis Sci. 1996 Oct;37(11):2146-56.
This study was conducted to examine the effect of retinal ischemia-reperfusion injury on protein tyrosine phosphorylation, the production of angiogenic growth factors, and the activation of signal proteins in tyrosine kinase pathways.
Ischemia-reperfusion injury was induced in rats by compression of the optic nerve for 2 hours. The rats were killed, and the retinas were collected at 0, 1, 6, 24, 48, 96, or 168 hours of reperfusion. Tyrosine phosphorylation of proteins in the retina was examined by Western blot analysis and immunohistochemistry. Angiogenic growth factors and their receptors, such as basic fibroblast growth factor (bFGF) and Flg, vascular endothelial growth factor (VEGF) and Flk-1, platelet-derived growth factor (PDGF)-B chain and PDGF-beta receptor, and five intracellular signal proteins (phosphatidylinositol 3-kinase [PI3K], phospholipase C gamma [PLC gamma], C-Src, SHC, and mitogen-activated protein kinase [MAPK]) were examined by Western blot analysis.
Protein tyrosine phosphorylation increased after ischemia-reperfusion injury, reaching a peak at 48 hours of reperfusion. Increased staining of tyrosine-phosphorylated proteins in the inner retina were evident on immunohistochemical examination. The amount of bFGF decreased after injury, but the amounts of VEGF and PDGF-B chain increased. Tyrosine phosphorylation of PLC gamma, SHC, and MAPK was increased at 48 hours of reperfusion, and tyrosine phosphorylation of PDGF-beta receptor and PI3K was increased at 168 hours of reperfusion.
Ischemia-reperfusion injury in the rat retina leads to activation of the tyrosine kinase pathway, increasing the amounts of angiogenic growth factors. The resultant activation of signal proteins PLC gamma, SHC, MAPK, PI3K, and PDGF-beta receptor may play an important role in ischemia-induced retinal changes such as cell proliferation.
本研究旨在探讨视网膜缺血再灌注损伤对蛋白质酪氨酸磷酸化、血管生成生长因子的产生以及酪氨酸激酶途径中信号蛋白激活的影响。
通过压迫大鼠视神经2小时诱导缺血再灌注损伤。在再灌注0、1、6、24、48、96或168小时处死大鼠并收集视网膜。通过蛋白质印迹分析和免疫组织化学检测视网膜中蛋白质的酪氨酸磷酸化。通过蛋白质印迹分析检测血管生成生长因子及其受体，如碱性成纤维细胞生长因子（bFGF）和Flg、血管内皮生长因子（VEGF）和Flk-1、血小板衍生生长因子（PDGF）-B链和PDGF-β受体，以及五种细胞内信号蛋白（磷脂酰肌醇3激酶[PI3K]、磷脂酶Cγ[PLCγ]、C-Src、SHC和丝裂原活化蛋白激酶[MAPK]）。
缺血再灌注损伤后蛋白质酪氨酸磷酸化增加，在再灌注48小时达到峰值。免疫组织化学检查显示视网膜内层酪氨酸磷酸化蛋白染色增加。损伤后bFGF量减少，但VEGF和PDGF-B链量增加。再灌注48小时时PLCγ、SHC和MAPK的酪氨酸磷酸化增加，再灌注168小时时PDGF-β受体和PI3K的酪氨酸磷酸化增加。
大鼠视网膜缺血再灌注损伤导致酪氨酸激酶途径激活，增加血管生成生长因子的量。信号蛋白PLCγ、SHC、MAPK、PI3K和PDGF-β受体的激活可能在缺血诱导的视网膜变化如细胞增殖中起重要作用。
