García-Ayuso Diego, Di Pierdomenico Johnny, Esquiva Gema, Nadal-Nicolás Francisco Manuel, Pinilla Isabel, Cuenca Nicolás, Vidal-Sanz Manuel, Agudo-Barriuso Marta, Villegas-Pérez María P
Instituto Murciano de Investigación Biosanitaria Hospital Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca) and Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Murcia, Spain.
Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, San Vicente del Raspeig, Alicante, Spain.
Invest Ophthalmol Vis Sci. 2015 Jul;56(8):4592-604. doi: 10.1167/iovs.15-16808.
To study the population of intrinsically photosensitive retinal ganglion cells (melanopsin-expressing RGCs, m+RGCs) in P23H-1 rats, a rat model of inherited photoreceptor degeneration.
At postnatal (P) times P30, P365, and P540, retinas from P23H dystrophic rats (line 1, rapid degeneration; and line 3, slow degeneration) and Sprague Dawley (SD) rats (control) were dissected as whole-mounts and immunodetected for melanopsin and/or Brn3a. The dendritic arborization of m+RGCs and the numbers of Brn3a+RGCs and m+RGCs were quantified and their retinal distribution and coexpression analyzed.
In SD rats, aging did not affect the population of Brn3a+RGCs or m+RGCs or the percentage that showed coexpression (0.27%). Young P23H-1 rats had a significantly lower number of Brn3a+RGCs and showed a further decline with age. The population of m+RGCs in young P23H-1 rats was similar to that found in SD rats and decreased by 22.6% and 28.2% at P365 and P540, respectively, similarly to the decrease of the Brn3a+RGCs. At these ages the m+RGCs showed a decrease of their dendritic arborization parameters, which was similar in both the P23H-1 and P23H-3 lines. The percentage of coexpression of Brn3a was, however, already significantly higher at P30 (3.31%) and increased significantly with age (10.65% at P540).
Inherited photoreceptor degeneration was followed by secondary loss of Brn3a+RGCs and m+RGCs. Surviving m+RGCs showed decreased dendritic arborization parameters and increased coexpression of Brn3a and melanopsin, phenotypic and molecular changes that may represent an effort to resist degeneration and/or preferential survival of m+RGCs capable of synthesizing Brn3a.
研究遗传性光感受器变性大鼠模型P23H - 1大鼠中内在光敏性视网膜神经节细胞（表达黑视蛋白的视网膜神经节细胞，m + RGCs）的数量。
在出生后（P）第30、365和540天，将P23H营养不良大鼠（第1系，快速变性；和第3系，缓慢变性）以及Sprague Dawley（SD）大鼠（对照）的视网膜制成整装片，进行黑视蛋白和/或Brn3a的免疫检测。对m + RGCs的树突分支以及Brn3a + RGCs和m + RGCs的数量进行定量，并分析它们在视网膜中的分布和共表达情况。
在SD大鼠中，衰老不影响Brn3a + RGCs或m + RGCs的数量，也不影响共表达的百分比（0.27%）。年轻的P23H - 1大鼠中Brn3a + RGCs的数量显著减少，且随年龄进一步下降。年轻P23H - 1大鼠中m + RGCs的数量与SD大鼠相似，在P365和P540时分别减少了22.6%和28.2%，与Brn3a + RGCs的减少情况相似。在这些年龄段，m + RGCs的树突分支参数降低，P23H - 1和P23H - 3系的情况相似。然而，Brn3a共表达的百分比在P30时已经显著更高（3.31%），并随年龄显著增加（P540时为10.65%）。
遗传性光感受器变性后，Brn3a + RGCs和m + RGCs会继发性丢失。存活的m + RGCs显示树突分支参数降低，Brn3a和黑视蛋白的共表达增加，这些表型和分子变化可能代表了m + RGCs抵抗变性和/或优先存活的努力，这些m + RGCs能够合成Brn3a。
