Pequignot M O, Provost A C, Sallé S, Menasche M, Saule S, Jaïs J-P, Abitbol M
Universite Paris Descartes, CERTO, EA # MRES 2502, Faculté de Médecine Paris Descartes - site Necker, Paris, France.
Mol Vis. 2011 Apr 20;17:989-96.
The aim of our work was to study apoptosis during the development of the retinal pigment epithelium (RPE) in mice between embryonic day (E) 10.5 and E12.5 and to examine a possible link between apoptosis and pigmentation.
We collected mouse embryos at E10.5, E11.5, and E12.5 and labeled apoptotic cells in 5-µm paraffin sections, using the terminal deoxynucleotidyl transferase dUTP nick end labeling technique. We counted the total number of cells and the number of apoptotic cells in the early developing RPE and calculated the percentage of apoptosis at each stage.
In the C57BL/6J mouse, 17% of the RPE cells were apoptotic at E10.5 compared to 0.9% at E12.5. At E11.5, three-quarters of the RPE cells began to pigment, and apoptotic cells were located mostly in the nonpigmented part. In contrast, in the BALB/c mouse (tyrosinase-deficient) and pJ mouse (carrying mutations in the p gene) hypopigmented strains, the RPE contained significantly fewer apoptotic cells (7.5% and 10.1%, respectively) at E10.5 than controls. Subsequently at E11.5 and E12.5, the two hypopigmented strains displayed different apoptotic patterns; the BALB/c RPE had a similar percentage of apoptotic cells to controls (1.5% and 1.1%, respectively, for BALB/c versus 3.0% and 0.9%, respectively, for C57BL/6J), whereas the pJ RPE contained significantly more apoptosis (7.5% and 3.5%, respectively). Overall we observed differences in the evolution of the relative total number of RPE cells between the three strains.
Apoptosis is a main event during the first stages of normal RPE development, indicating an essential role during RPE differentiation. Moreover, the early apoptotic pattern and possibly the whole early development of the RPE is different between hypopigmented and pigmented strains, as well as between BALB/c and pJ mice. This suggests the existence of regulatory and developmental differences with a more complex origin than just differing pigmentation levels.
我们研究的目的是探讨小鼠胚胎期第10.5天（E10.5）至第12.5天（E12.5）视网膜色素上皮（RPE）发育过程中的细胞凋亡情况，并检验细胞凋亡与色素沉着之间可能存在的联系。
我们收集了E10.5、E11.5和E12.5的小鼠胚胎，采用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记技术，对5微米厚的石蜡切片中的凋亡细胞进行标记。我们统计了早期发育的RPE中的细胞总数和凋亡细胞数，并计算了每个阶段的凋亡百分比。
在C57BL/6J小鼠中，E10.5时17%的RPE细胞发生凋亡，而E12.5时为0.9%。在E11.5时，四分之三的RPE细胞开始色素沉着，凋亡细胞主要位于未色素沉着的部分。相比之下，在低色素沉着品系BALB/c小鼠（酪氨酸酶缺陷型）和pJ小鼠（p基因携带突变）中，E10.5时RPE中的凋亡细胞明显少于对照组（分别为7.5%和10.1%）。随后在E11.5和E12.5时，这两个低色素沉着品系表现出不同的凋亡模式；BALB/c RPE的凋亡细胞百分比与对照组相似（BALB/c分别为1.5%和1.1%，而C57BL/6J分别为3.0%和0.9%），而pJ RPE中的凋亡明显更多（分别为7.5%和3.5%）。总体而言，我们观察到这三个品系之间RPE细胞相对总数的演变存在差异。
细胞凋亡是正常RPE发育早期阶段的一个主要事件，表明其在RPE分化过程中起重要作用。此外，低色素沉着品系和色素沉着品系之间，以及BALB/c和pJ小鼠之间，RPE的早期凋亡模式以及可能的整个早期发育是不同的。这表明存在调控和发育差异，其起源比仅仅色素沉着水平不同更为复杂。
