Pe'er J, Zajicek G, Greifner H, Kogan M
Department of Ophthalmology, Hadassah University Hospital, Jerusalem, Israel.
Anat Rec. 1996 May;245(1):36-40. doi: 10.1002/(SICI)1097-0185(199605)245:1<36::AID-AR6>3.0.CO;2-D.
Epithelial proliferation is linked with cell displacement. When a cell divides, one of its progeny replaces the dividing ancestor and the other is displaced into a more remote location that has to be vacated first by peripheral cells. As cells are neither pushed nor pulled in a mechanical sense, and since they do not move by their own means, this displacement is best regarded as streaming. The purpose of the present study was to measure epithelial cell streaming in adult rat conjunctiva.
Twenty-seven female adult rats were injected i.p. with 18.5 KBq [3H]-thymidine/g body weight, specific activity 185 GBq/mMol. Three rats were killed at different times up to 28 d. Eyes and eyelids were removed in one piece, cut along the pupillary-optic nerve line into 5-microns-thick sections, and prepared for autoradiography. In each eye, the entire upper conjunctiva extending from limbus to the palpebral muco-cutaneous junction was scanned with an ocular micrometer grid. The limbus served as point of origin. The x, y coordinate of each nucleus with two grains or more and its grain content were recorded.
One hour after labeling, labeled cells were spread evenly along the basal layer. Cells of the upper layers were not labeled. As time passed by, labeled cells in the fornix became more abundant, while in the limbus and palpebral margin, their frequency declined. Labeled cells streamed from the limbus and palpebral muco-cutaneous junction to the fornix. Bulbar conjunctival epithelia streamed at a velocity of 13.2 microns/day. Epithelia in the palpebral conjunctiva streamed at a velocity of 11.8 microns/day. At the same time cells streamed from the basal layer to the epithelial surface at a velocity of 0.4 microns/day. Generation time was 3.9 days.
Bulbar and palpebral conjunctivae are two independent cell kinetic systems that originate in two stem cell regions, one in the limbus and the other in the muco-cutaneous junction. Each system is made of two compartments, a progenitor where cells proliferate, and a compartment of non proliferating end cells. Progenitors created in the first, enter the second and turn into end cells. Ultimately they die in the fornix. The undetermined limbus stem cell generates two epithelial cell lines, a corneal and a conjunctival.
上皮细胞增殖与细胞移位有关。当一个细胞分裂时，其一个子代细胞取代分裂的亲代细胞，另一个则移位到更远处的位置，而该位置必须先由周边细胞腾出。由于细胞在机械意义上既不被推动也不被拉动，且它们不会自行移动，这种移位最好被视为流动。本研究的目的是测量成年大鼠结膜中的上皮细胞流动。
27只成年雌性大鼠腹腔注射18.5 kBq/克体重的[³H] - 胸腺嘧啶核苷，比活度为185 GBq/毫摩尔。在长达28天的不同时间点处死3只大鼠。将眼睛和眼睑完整取下，沿瞳孔 - 视神经线切成5微米厚的切片，并准备进行放射自显影。在每只眼中，用目镜测微网格扫描从角膜缘延伸至睑粘膜 - 皮肤交界处的整个上结膜。角膜缘作为原点。记录每个含有两个或更多银粒的细胞核的x、y坐标及其银粒含量。
标记后1小时，标记细胞沿基底层均匀分布。上层细胞未被标记。随着时间推移，穹窿部的标记细胞变得更加丰富，而在角膜缘和睑缘，其频率下降。标记细胞从角膜缘和睑粘膜 - 皮肤交界处流向穹窿部。球结膜上皮细胞以13.2微米/天的速度流动。睑结膜上皮细胞以11.8微米/天的速度流动。同时，细胞以0.4微米/天的速度从基底层流向上皮表面。细胞周期为3.9天。
球结膜和睑结膜是两个独立的细胞动力学系统，起源于两个干细胞区域，一个在角膜缘，另一个在粘膜 - 皮肤交界处。每个系统由两个区室组成，一个是细胞增殖的祖细胞区室，另一个是非增殖终末细胞区室。在第一个区室产生的祖细胞进入第二个区室并转变为终末细胞。最终它们在穹窿部死亡。未确定的角膜缘干细胞产生两条上皮细胞系，一条是角膜上皮细胞系，另一条是结膜上皮细胞系。
