Góes Rejane Maira, Barbosa Flávia Leão, De Faria-E-Sousa Sidney Júlio, Haddad Antonio
Departamento de Biologia, São Paulo State University, IBILCE, UNESP, São Paulo, Brasil.
Anat Rec (Hoboken). 2008 Feb;291(2):191-203. doi: 10.1002/ar.20635.
The investigation was centered on the morphological features of the conjunctiva-cornea transition (limbus) of the rabbit eye and the proliferative behavior of its epithelium. The eyes were processed for examination with light and electron microscopy, as well as for autoradiography after intravitreal injection of [(3)H]thymidine ([(3)H]TdR). At the sites of extraocular muscle insertion, the vascularization of the stroma extended to the peripheral cornea, and the limbal epithelium was thin with its basal stratum made up by clear cuboidal cells. In between the muscle insertions, the cuboidal clear cells, as well as the stroma blood vessels, were scarce. At the light microscope level, the basement membrane was distinct in the cornea but not in the limbus or the conjunctiva. Autoradiographs demonstrated that, at the limbus, the basal cells migrated very quickly to the suprabasal region and remained there up to the 28-day interval. Labeled cells were identified in all epithelial layers of the cornea, including the basal one, at 21 and 28 days but not in the limbal basal clear cells. The rate of renewal of conjunctival epithelium was similar to that observed for the transition with scarce clear cells. The high-resolution autoradiographs demonstrated that the basal cuboidal clear limbal cells exhibit a quick renewal and that they are not label-retaining cells. These latter ones were detected all over the corneal epithelium and in the suprabasal layers of the limbus up to 28 days, in physiological conditions, without the need of stimulation by damage to the corneal epithelium.
该研究聚焦于兔眼角膜-结膜移行处（角膜缘）的形态特征及其上皮细胞的增殖行为。对兔眼进行处理，以便进行光镜和电镜检查，以及在玻璃体内注射[³H]胸腺嘧啶核苷（[³H]TdR）后进行放射自显影。在眼外肌附着部位，基质的血管化延伸至周边角膜，角膜缘上皮较薄，其基底细胞层由透明立方细胞组成。在肌肉附着点之间，立方透明细胞和基质血管较少。在光镜水平，角膜的基底膜清晰可见，而角膜缘和结膜的基底膜则不明显。放射自显影片显示，在角膜缘，基底细胞迅速迁移至上基底区域，并在28天的观察期内一直停留在该区域。在第21天和第28天，在角膜的所有上皮层（包括基底细胞层）中均发现有标记细胞，但角膜缘基底透明细胞中未发现。结膜上皮的更新速率与透明细胞较少的移行部位相似。高分辨率放射自显影片显示，角膜缘基底立方透明细胞更新迅速，且不是标记保留细胞。在生理条件下，直至28天，在整个角膜上皮和角膜缘的上基底层中均可检测到标记保留细胞，无需角膜上皮损伤刺激。
