摘要
OBJECTIVE: To investigate in vivo survival of retinal ganglion cells (RGCs) after partial blockage of optic nerve (ON) axoplasmic flow by sub-retinal space or vitreous cavity injection of brain-derived neural factor (BDNF) produced by genetically modified neural progenitor cells (NPCs). METHODS: Adult Sprague-Dawley (SD) rat RGCs were labeled with granular blue (GB) applied to their main targets in the brain. Seven days later, the left ON was intra-obitally crushed with a 40 g power forceps to partially block ON axoplasmic flow. Animals were randomized to three groups. The left eye of each rat received a sham injection, NPCs injection or an injection of genetically modified neural progenitors producing BDNF (BDNF-NPCs). Seven, 15 and 30 days after ON crush, retinas were examined under a fluorescence microscope. By calculating and comparing the average RGCs densities and RGC apoptosis density, RGC survival was estimated and the neuro-protective effect of transplanted cells was evaluated. RESULTS: Seven, 15 and 30 days after crush, in the intra-vitreous injection group, mean RGC densities had decreased to 1885 +/- 68, 1562 +/- 20, 1380 +/- 7 and 1837 +/- 46, 1561 +/- 58, 1370 +/- 16, respectively with sham injection or neural progenitors injection. However, RGCs density in the groups treated with intra-vitreous injection of BDNF-NPC was 2101 +/- 15, 1809 +/- 19 and 1625 +/- 34. Similar results were found in groups after sub-retinal injection. Higher densities were observed in groups treated with BDNF-NPCs. There were statistically significant differences among groups through nonparametric tests followed by the Mann-Whitely test. RGC apoptosis density in BDNF-NPC at each follow-up time was less than in other groups. CONCLUSIONS: A continuous supply of neurotrophic factors by the injection of genetically modified neural progenitors presents a highly effective approach to counteract optic neuropathy and RGC degeneration after partial ON axoplasmic flow blockage.
目的 观察脑源性神经营养因子 (brain derivednurotrophicfactor,BDNF)基因修饰的神经前体细胞 (neuralprogenitorcells ,NPCs)玻璃体腔或视网膜下腔移植对视神经轴浆流部分中断视神经病变的治疗作用。方法 视网膜神经节细胞经外侧膝状行逆行标记 ,7天后用 4 0g力量大小的轴浆流运输钳压迫视神经 ,制作视神经轴浆流运输部分中断动物模型。动物随机分成 3组 ,将视神经轴浆流运输部分中断的大鼠玻璃体腔内或视网膜下腔注入BDNF基因修饰的NPCs (BDNF NPCs) ,注射生理盐水为阴性对照 ,而注射单纯的NPCs为载体细胞对照。 7,15及 30天后通过RGCs的平均密度计数以及RGCs的平均凋亡密度计数并进行统计分析比较不同处理组间的差别 ,对BDNF NPCs表达的BDNF及其保护作用评价。结果 部分轴浆流运输中断后的大鼠玻璃体腔内注射生理盐水的阴性对照及注入单纯NPCs组 ,7天 ,15天及 30天RGCs的平均密度分别为 1885± 6 8,15 6 2± 2 0 ,1380± 7和 1837± 4 6 ,15 6 1± 5 8,1370± 16。而在玻璃体腔内注射DNF NPCs组为 2 10 1± 15 ,180 9± 19和 16 2 5± 34。在视网膜下腔注入组也获得了相似的结果。对RGCs的平均凋亡密度进行比较 ,BDNF NPCs处理组较其它组低。在相应的时间点 ,BDNF NPCs处理组较其它组经非参数检?
基金
ThisstudywassupportedbygrantsfromtheNationalNaturalSciencFoundationofChina (No 3 9670 775or39770811)andGuangdongKeyProgram (1998)
