M. Zhao et al., HUMAN CORNEAL EPITHELIAL-CELLS REORIENT AND MIGRATE CATHODALLY IN A SMALL APPLIED ELECTRIC-FIELD, Current eye research, 16(10), 1997, pp. 973-984
Purpose. To test whether human corneal epithelial cells (HCECs) respon
d to small applied electric fields (EFs) in a similar manner to bovine
corneal epithelial cells (BCECs), the orientation and directed migrat
ion in small EFs of both primary cultures and of a human corneal epith
elial cell line were quantified.Methods. Primary cultures of human cor
neal epithelial cells (PHCECs) and transformed human corneal epithelia
l cells (THCECs) were exposed to EFs (100 mV/mm-250 mV/mm) in differen
t media. Cell migration was traced using an image analyser. Results. P
HCECs and THCECs reoriented and migrated towards the cathode (negative
pole) when cultured in small direct current (de) EFs. Both the reorie
ntation and directional migration were voltage-and serum-dependent. as
shown previously for bovine cells. PHCECs and THCECs showed significa
nt perpendicular orientation in EFs at 150 mV/mm in medium with serum,
while at the same voltage, no significant orientation was found in se
rum free medium. PHCECs started to show perpendicular reorientation ar
ound 30 min after onset of EF at 150 mV/mm. They showed significant di
rectional migration at 150 mV/mm, with directedness of 0.35 +/- 0.07 a
nd a migration rate of 9.1 +/- 0.7 mu m/h (n = 90), both significantly
higher than that of cells in serum free medium. Addition of EGF induc
ed significant reorientation and directional migration of THCECs at 10
0 mV/mm. Additionally, as for BCECs, which remained viable and respons
ive to electric fields for at least 75 h at 150 mV/mm, THCECs also rem
ained viable and showed responsiveness during long periods of exposure
to EFs (at least 20 h). Conclusions. Cultured human primary CECs and
a human corneal epithelial cell line both responded to small EFs with
perpendicular reorientation and cathodally-directed migration. Cell re
sponses were qualitatively similar to those reported previously for bo
vine CECs. The endogenous EFs generated by wounded cornea may play an
important role in promoting cell shape changes and directed migration
of CECs during the healing process.