Zhang Chun, Xu Yong-Sheng, Wang Wei, Tso Mark O M
Peking University Eye Center, the Third Hospital of Peking University, Beijing, China.
Zhonghua Yan Ke Za Zhi. 2007 Oct;43(10):922-7.
To study neuronal excitotoxicity induced by subretinal injection of glutamate analogues.
We injected 30 mmol/L N-methyl-D-aspartate (NMDA) in 10 microl of DMEM/F12 into subretinal blebs in 24 one-month-old rabbits that were killed 0.5, 1, 2 or 7 days after injection. The retinas were studied histopathologically by light and electronic microscope. The horizontal cells, rod bipolar cells and amacrine cells were labeled by antiserum against calbindin, protein kinase Calpha, and calretinin, respectively. TUNEL labeling was performed to identify apoptotic cells.
Compared with vehicle injected control retina, treated retina showed an early and severe morphological changes in both amacrine and ganglion cells and scattered densification in photoreceptor nuclei at acute stage (<1 d), all retinal neurons damage at the intermediate phase (2 d), and a significant loss of cells in all layers of the retina at the chronic phase (7 d), respectively. Horizontal, amacrine and ganglion cells were reduced after subretinal injection of NMDA. The number of rod bipolar cells had little change. The morphological changes of neuronal death included apoptosis, necrosis, hydropic degeneration and karyorrhectic cell death. TUNEL positive nuclei were significantly (P < 0.01) increased in all retinal layers at the acute phases after NMDA administration.
NMDA administration into sub-retina induces excitotoxicity in photoreceptor, horizontal, rod bipolar, amacrine, and ganglion cells of retina, which is different from the other models of retinal cultures and intravitreal injection that only cause neuronal death in the inner retina.
研究视网膜下注射谷氨酸类似物诱导的神经元兴奋性毒性。
将10微升含30毫摩尔/升N-甲基-D-天冬氨酸（NMDA）的DMEM/F12注射到24只1月龄家兔的视网膜下泡中，分别在注射后0.5、1、2或7天处死动物。通过光镜和电镜对视网膜进行组织病理学研究。分别用抗钙结合蛋白、蛋白激酶Cα和钙视网膜蛋白的抗血清标记水平细胞、视杆双极细胞和无长突细胞。采用TUNEL标记法鉴定凋亡细胞。
与注射溶剂的对照视网膜相比，处理后的视网膜在急性期（<1天）无长突细胞和神经节细胞出现早期严重形态学改变，光感受器细胞核散在致密化；在中期（2天）所有视网膜神经元均受损；在慢性期（7天）视网膜各层细胞均显著丢失。视网膜下注射NMDA后，水平细胞、无长突细胞和神经节细胞数量减少。视杆双极细胞数量变化不大。神经元死亡的形态学改变包括凋亡、坏死、水样变性和核固缩性细胞死亡。NMDA给药后急性期所有视网膜层TUNEL阳性细胞核显著增加（P<0.01）。
视网膜下注射NMDA可诱导视网膜光感受器、水平细胞、视杆双极细胞、无长突细胞和神经节细胞发生兴奋性毒性，这与仅导致视网膜内层神经元死亡的其他视网膜培养和玻璃体内注射模型不同。
