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Epithelial cells in hypoxic culture show enhanced proliferation, inhibited differentiation
Hypoxic culture enhances proliferation and inhibits differentiation of human limbal epithelial progenitor cells in vitro, according to a study by researchers in Japan.
Hideyuki Miyashita and colleagues investigated the proliferation and differentiation of primary human limbal epithelial cells harvested from the rim of donor corneas in hypoxic culture conditions (2% O2) and standard culture conditions (20% O2), according to the study.
Both colony-forming efficiency and proliferation of the epithelial cells were significantly enhanced in hypoxic culture. Flow cytometry revealed a higher fraction of hypoxic cells in the G0/G1-phase and fewer cells in the S-phase compared with cells in standard culture conditions, the authors reported.
However, the researchers observed no difference between the cell groups in the uptake of BrdU during a 2-hour pulse, suggesting that hypoxic colonies contained rapidly cycling cells, they said.
Additionally, TUNEL assay showed that apoptotic cells were sparse in both groups, and hypoxic cells showed lower forward scatter compared with cells in standard culture, the authors noted.
Immunohistochemistry showed no difference in the staining pattern of K15, p63 and Ki67 between the two groups, but cells cultivated in standard oxygen conditions expressed higher levels of the differentiation markers involucrin and K3, according to the study.
The study is published in the August issue of Investigative Ophthalmology & Visual Science.