Abstract
Purpose: :
Resolvins, derived from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), contribute to the resolution of immune responses. Since inflammation retards wound healing, we hypothesizsed that exposure to resolvins also would hasten wound closure through stimulation of cell migration. Accordingly, we determined using cultured human corneal epithelial cells (HCEC) in a scratch wound assay if exposure to resolvins would stimulate cell migration.
Methods: :
Resolvin-induced effects on wound closure were determined in a scratch wound assay with SV40-immortalized HCEC. Cells were seeded onto 6-well plates and grown to 80% confluence. After overnight exposure to serum-free medium, the cultures were wounded using a sterile pipette tip to create two perpendicular linear scrapes. Floating cells were removed and the culture was replenished with medium in the absence or presence of resolvin E1 (RvE1), resolvin analog (RX-10008), or the positive control EGF. Hydroxyurea (5 mM) was added to reduce cell proliferation. Wound closure rates were monitored using an inverted microscope and photographing the wound area at 5 and 24 h. To further elucidate the effects of RvE1 and RX-10008, additional experiments were performed in the presence of wortmannin, a PI3-K inhibitor, and tyrphostin AG1478, an EGFR tyrosine kinase inhibitor.
Results: :
RvE1 and RX-10008 effectively increased HCEC migration at a concentration of 10-7 M. Compared to untreated controls, the normalized rate was increased to 1.64 ± 0.09 and 1.84 ± 0.12 (n=10) for RvE1 and RX-10008, respectively at 24 hours with significant closure seen already at 5 hours. The effect was blocked by exposure to either 0.1 µM wortmannin or 1 µM tyrphostin AG 1478. The normalized migration rate obtained with EGF at 10 ng/mLwas 1.99 ± 0.18 (n=10). Neither RvE1 nor RX8 could further enhance EGF-stimulated migration.
Conclusions: :
Resolvins enhanced injury-induced HCEC wound closure by stimulating their migratory activity by about 70%. Inhibition of the effect by either wortmannin or AG1478 suggest that the resolvins investigated may transactivate the EGF-receptor. Resolvins could be novel therapies to improve corneal wound healing.
Keywords: cornea: epithelium • wound healing • signal transduction