TRPC6 Channel Protects Retinal Ganglion Cells in a Rat Model of Retinal Ischemia/Reperfusion-Induced Cell Death
TRPC6 Channel Protects Retinal Ganglion Cells in a Rat Model of Retinal Ischemia/Reperfusion-Induced Cell Death
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TRPC6 通道在视网膜缺血/再灌注诱导的细胞死亡大鼠模型中保护视网膜神经节细胞
DOI：
10.1167/iovs.10-5451
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发表时间：
2010-11-01
影响因子：
4.4
通讯作者：
Zhang, Xiulan
中科院分区：
文献类型：
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作者：
Wang, Xiaolei;Teng, Leilei;Zhang, Xiulan
目的.探讨瞬时受体电位经典6（TRPC 6）在大鼠视网膜缺血再灌注（IR）模型视网膜神经节细胞（RGCs）存活中的作用。采用RT-PCR、Western blot、原位杂交和免疫组化等方法检测TRPC 6在正常大鼠视网膜中的表达。建立大鼠视网膜IR模型，然后评估TRPC 6表达的时程。进行了药理学实验。在视网膜IR模型中测定脑源性神经营养因子（BDNF）的表达。通过计数12个标准视网膜区域中荧光金标记的细胞来估计存活的RGC的密度。TRPC 6 mRNA和蛋白质选择性地富集在视网膜的RGC层中。视网膜缺血60 min可诱导TRPC 6 mRNA和蛋白表达升高，再灌注24 h达高峰。1周后TRPC 6蛋白表达显著下降，伴随着大量的RGC丢失。TRPC通道的激动剂显著增加RGC存活，而拮抗剂降低细胞密度。bdnf基因的转录水平在24小时增强;这与TRPC 6的增加相一致。当TRPC 6被阻断时，BDNF前体（proBDNF）在24小时增加，而不是其成熟形式（mBDNF）。本研究记录了TRPC 6在视网膜IR模型中的表达模式，并提供了在缺血前激活TRPC通道对体内RGC具有早期神经保护作用的证据。TRPC 6的保护作用是由BDNF介导的，proBDNF-p75 NTR信号通路可能参与了视网膜缺血损伤中RGCs的死亡。（Invest Ophthalmol维斯科学。2010;51：5751-5758）DOI：10.1167/iovs.10-5451
PURPOSE. To examine the potential role of transient receptor potential canonical 6 (TRPC6) in the survival of retinal ganglion cells (RGCs) in the rat retinal ischemia/reperfusion (IR) model.METHODS. TRPC6 expression in normal rat retina was analyzed by RT-PCR, Western blot analysis, in situ hybridization, and immunohistochemistry. The rat retinal IR model was established, and then the time course of TRPC6 expression was evaluated. Pharmacologic experiments were conducted. The expression of brain-derived neurotrophic factor (BDNF) was measured in the retinal IR model. Densities of surviving RGCs were estimated by counting fluorogold-labeled cells in 12 standard retinal areas.RESULTS. TRPC6 mRNA and protein are selectively enriched in the RGC layer of the retina. A 60-minute interval of retinal ischemia could induce the elevation of TRPC6 mRNA and protein, both of which peaked 24 hours after reperfusion. TRPC6 protein expression decreased dramatically 1 week later, accompanied by substantial RGC loss. The TRPC channel's agonist significantly increased RGC survival, and the antagonist reduced cell density. The transcription level of the bdnf gene was enhanced at 24 hours; this paralleled the increase of TRPC6. When TRPC6 was blocked, the BDNF precursor (proBDNF), rather than its mature form (mBDNF), increased at 24 hours.CONCLUSIONS. This study documents the pattern of TRPC6 expression in the retinal IR model and provides evidence that activating TRPC channels before ischemia has early neuroprotective effects on RGCs in vivo. The protection of TRPC6 is BDNF mediated, and proBDNF-p75NTR signaling may contribute to the death of RGCs in retinal ischemia injury. (Invest Ophthalmol Vis Sci. 2010;51:5751-5758) DOI:10.1167/iovs.10-5451