TY - JOUR
T1 - Subthreshold UV light-induced peroxide formation in cultured corneal epithelial cells
AU - Shimmura, S.
AU - Suematsu, M.
AU - Shimoyama, M.
AU - Tsubota, K.
AU - Oguchi, Y.
AU - Ishimura, Y.
PY - 1996/2/15
Y1 - 1996/2/15
N2 - Purpose: To demonstrate intracellular peroxide formation in cultured corneal epithelial cells by subthreshold ultraviolet (UV) light, and the protective effects of lactoferrin as an antioxidant. Methods: Intracellular oxidative insults and cell viability of rabbit corneal epithelial cells (RCEC) were assessed by dual-color digital microfluorography using carboxydichlorofluorescin (CDCFH) diacetate bis acetoxymethyl ester, a hydroperoxide-sensitive fluoroprobe, and propidium iodide (PI), respectively. The magnitude of UV-induced oxidative insults was calibrated by concentrations of exogenously applied H2O2 which evoke compatible levels of CDCFH oxidation. Inhibition of peroxide formation by lactoferrin, a potent iron-chelating protein present abundantly in tear fluids, was evaluated. Results: Exposure of RCEC to low dose UV-B (2.0 mJ/cm2) caused intracellular oxidative changes which were equivalent to those elicited by 250 μM hydrogen peroxide. The UV-induced changes were dose dependent, non-necrotic, and were partially inhibited by lactoferrin (1 mg/ml) but not by iron-saturated lactoferrin. Pretreatment with deferoxamine (2 mM) or catalase (100 u/ml) also attenuated the UV-induced oxidative stress. Conclusions: UV light comparable to solar irradiation levels caused significant intracellular peroxide formation in corneal epithelial cells. The UV-induced oxidative stress was suppressed by lactoferrin, indicating that lactoferrin in tears may have a physiological role in protecting the corneal epithelium from solar UV irradiation.
AB - Purpose: To demonstrate intracellular peroxide formation in cultured corneal epithelial cells by subthreshold ultraviolet (UV) light, and the protective effects of lactoferrin as an antioxidant. Methods: Intracellular oxidative insults and cell viability of rabbit corneal epithelial cells (RCEC) were assessed by dual-color digital microfluorography using carboxydichlorofluorescin (CDCFH) diacetate bis acetoxymethyl ester, a hydroperoxide-sensitive fluoroprobe, and propidium iodide (PI), respectively. The magnitude of UV-induced oxidative insults was calibrated by concentrations of exogenously applied H2O2 which evoke compatible levels of CDCFH oxidation. Inhibition of peroxide formation by lactoferrin, a potent iron-chelating protein present abundantly in tear fluids, was evaluated. Results: Exposure of RCEC to low dose UV-B (2.0 mJ/cm2) caused intracellular oxidative changes which were equivalent to those elicited by 250 μM hydrogen peroxide. The UV-induced changes were dose dependent, non-necrotic, and were partially inhibited by lactoferrin (1 mg/ml) but not by iron-saturated lactoferrin. Pretreatment with deferoxamine (2 mM) or catalase (100 u/ml) also attenuated the UV-induced oxidative stress. Conclusions: UV light comparable to solar irradiation levels caused significant intracellular peroxide formation in corneal epithelial cells. The UV-induced oxidative stress was suppressed by lactoferrin, indicating that lactoferrin in tears may have a physiological role in protecting the corneal epithelium from solar UV irradiation.
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M3 - Article
AN - SCOPUS:33750163415
SN - 0146-0404
VL - 37
SP - S355
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
IS - 3
ER -