不同年龄人角膜缘基底细胞增殖力和超微结构观察

目的 评价不同年龄段人角膜缘基底细胞增殖力和超微结构的差异.方法 采用病例对照研究方法.2007至2008年于复旦大学附属眼耳鼻喉科医院眼库取材新鲜角膜缘组织40例样本,按供体年龄编入4组,每组10例.A组供体年龄为0～19岁,B组为20～39岁,C组为40～59岁,D组为60～79岁.各年龄段组的10例角膜缘组织行细胞核增殖抗原(PCNA)免疫组织化学染色,观察角膜缘上皮染色情况并对基底细胞染色阳性率进行分级.同时对各年龄段组角膜缘组织行透射电子显微镜观察,比较各年龄段组角膜缘基底上皮细胞超微结构特点.结果 A组样本中,角膜缘基底上皮细胞核PCNA染色呈强阳性(++++)占5例(50%),其余3个年龄段组强阳性染色明显减少,而以弱阳性(+)染色为主,分别为4例(40%)、6例(60%)、5例(50%).此外,仅A组中可见3例样本浅表上皮细胞核染色和1例样本细胞质染色.在透射电镜下观察,A组的干细胞样细胞具有3个特点,即胞体极小、细胞平行于基底膜方向伸展、细胞核内致密团块状异染色质多.其余3个年龄段组中,干细胞样细胞与相邻基底细胞大小差异较小,细胞垂直于基底膜方向伸展,细胞核内以常染色质为主.结论 不同年龄人角膜缘基底细胞增殖力大小存在差异,且细胞超微结构呈现不同特点.

Proliferative ability and ultramicrostructure of basal limbal epithelial cells in different age group of normal subjects

Objective To demonstrate the difference in proliferative ability and ultramicrostracture of basal limbal epithelial cells in different age group of normal subjects. Methods It is a case-control study. 40 specimens of limbas from 40 eyes provided by the eye bank of Eye Ear Nose and Throat Hospital of Fudan University in 2007-2008 were enrolled in this study. Only one eye was enrolled from the same donner. Specimens were divided into 4 groups according to the donners' age: A (0-19 years), B (20-39 years), C (40-59 years) and D(60-79 years). Immunohistochemistry of proliferating cell nuclear antigen (PCNA) was performed on 10 specimens of each group. The staining status of limbal epithelium was observed and the staining positive rate of the limbal basal epithelial cells was graded. And transmission electric microscopy was performed on specimens of each group. The morphologic feature of the ultrsmicrostructure of limbal basal epithelial cells were observed. Results 50% of specimens in group A showed a strong PCNA staining of ( ++++ ), while a weak staining of ( + ) took a main part in all the other 3 groups ( B 40%, C 60% and D 50%, respectively). Furthermore, positive nuclear staining of limbal superficial cells was observed in 3 specimens and positive cytoplasm staining was observed in 1 specimen, all in group A. Transmission electric microscopy showed that the stemcell-like cells in group A possessed 3 morphologic features: extremely small, stretching along the basal membrane, with densely packed heterochromatin. In contrast, the stemcell-like cells in the other 3 groups did not show great disparity in cell size with their neighbor epithelial cells, and they stretched vertically to the basal membrane, with dispersed euchromatin. Conclusion Difference in proliferative ability and ultramicrostructure of basal limbal epithelial cells was found in different age group of normal subjects.