To investigate the biological characters of limbal cells and evaluate the effect of cultivated human limbal epithelial cells transplantation on ocular surface reconstruction.Human limbal cells were isolated and cultivated in vitro. Immunofluorescence staining and RT-PCR were used to study the phenotype of the cells, BrdU labeling test was used to identify the slow-cycling cells in the cultures. Limbal stem cell deficiency (LSCD) was established in rat cornea by alkali burn. Two weeks after the injury, the rats received transplantation of cultivated human limbal epithelial cells with amniotic membrane carrier, and then the therapeutic effects were evaluated by slit lamp observation, HE staining and immunofluorescent staining.On day 7, p63 and K19 were strongly expressed by most cells, only a few cells expressed K3. On day 14 and day 21, p63 and K19 were still expressed by a majority of cells, while the proportion of K3 positive cells increased, some cells co-expressed p63 and K3. RT-PCR showed that gene expression of both p63 and K12 were positive in cultivated limbal cells, but in mature superficial epithelial cells only K12 was detected. Slow-cycling cells were observed after cultured for 21 days with BrdU free medium. Four weeks after limbal stem cells combined amniotic membrane transplantation (LSAT), both slit lamp observation and HE staining showed that LSAT relieved the pathological changes of rat cornea notably as compared with the amniotic membrane transplantation (AMT) group and control group. The rats that received LSAT exhibited reconstructed corneas with the intact epithelium and improved transparency. Immunofluorescence staining showed that a majority of the rat corneal epithelial cells stained positively to anti-human nuclear antibody and K3 antibody.P63 is not exclusively expressed by limbal stem cells (LSCs), a certain amount of p63 may also expressed by transient amplifying cells, LSCs are identified as p63 and K19 positive, K3/K12 negative cells. The detection of slow-cycling cells in the culture confirms that LSCs can be cultivated in vitro. Cultivated LSCs combine with amniotic membrane transplantation can functionally reconstruct the cornea suffered with LSCD.
