Wei Yong, Wang Ningli, Lu Qingjun, Zhang Nan, Zheng Deyu, Li Junfa
Beijing TongRen Eye Center, Beijing Tongren Hospital; Vision Science Laboratory, School of Ophthalmology, Capital Medical University, Beijing 100730, China.
Neurosci Lett. 2007 Dec 18;429(2-3):169-74. doi: 10.1016/j.neulet.2007.10.012. Epub 2007 Oct 22.
Elevated introcular pressure (IOP)-induced retinal neuron ischemic death includes an early phase of necrosis and prolonged phase of apoptosis. We used this ischemic model to observe the changes of sortilin and p75(NTR) protein expressions in rat retina. The results of Western blot analysis showed the expression of p75(NTR) at the band of 75 (mature form), 60 (non-glycosylated pieces) and 50 kDa (ectodomain shedding pieces), and the expression of sortilin at the 95 and 90 kDa (the mature form). The protein expressions of p75(NTR) (60 and 50 kDa pieces) and sortilin (90 kDa) increased significantly (p < 0.05) at days 3, 5 and 7 after retinal ischemia. This effect was also confirmed by immunofluorescence staining. Sortilin was primarily present in cell membrane of the ganglion cells layer (GCL) and large ganglion cell bodies by immunofluorescence labeling. There was little expression of p75(NTR) in the normal retina, while expression increased extensively in GCL, inner plexiform layer (IPL) and inner nuclear layer (INL) after retinal ischemia. p75(NTR) was shown to co-localize with neurofilament in the axons of neuronal cells by double-labeling. These results suggested that the protein expressions of 60 and 50 kDa forms of p75(NTR), and the 90 kDa mature form of sortilin increased in ischemia-induced retinal neuron of rats.
眼压升高（IOP）诱导的视网膜神经元缺血性死亡包括坏死的早期阶段和凋亡的延长阶段。我们利用这种缺血模型观察大鼠视网膜中sortilin和p75（NTR）蛋白表达的变化。蛋白质印迹分析结果显示，p75（NTR）在75 kDa（成熟形式）、60 kDa（非糖基化片段）和50 kDa（胞外域脱落片段）条带处表达，sortilin在95 kDa和90 kDa（成熟形式）处表达。视网膜缺血后第3、5和7天，p75（NTR）（60 kDa和50 kDa片段）和sortilin（90 kDa）的蛋白表达显著增加（p < 0.05）。免疫荧光染色也证实了这一效应。通过免疫荧光标记，sortilin主要存在于神经节细胞层（GCL）的细胞膜和大神经节细胞体中。正常视网膜中p75（NTR）表达很少，但视网膜缺血后在GCL、内网状层（IPL）和内核层（INL）中表达广泛增加。通过双重标记显示p75（NTR）与神经丝在神经元细胞的轴突中共定位。这些结果表明，在大鼠缺血诱导的视网膜神经元中，60 kDa和50 kDa形式的p75（NTR）以及90 kDa成熟形式的sortilin的蛋白表达增加。
