Protection Of CoQ10 On Human Keratinocyte Damaged From UVB Irradiation.

Background Skin is frequently exposed to UV light and increased risks for photooxidative damage as increasing atmospheric pollution and ozonosphere destroying, epidemiological survey indicate that UVB irradiation is relative to photoaging of skin. Recently, the unifying standpoint about mechanism of photoaging is that the unbalance between oxidant system and antioxidant defense system of the skin result in the skin damage, such as the overall ROS load and the deplete of antioxidant of the skin .So antioxidant should be applicated in skin in order to prevent ROS induced photoaging. The present study indicate CoQ10 is endogenous antioxidant ,which play a crucial role in the free radical scavenging in the skin. But age-relate CoQ10 changes and deficiency state have been described, therefore CoQ10 supplement may be very helpful to prevent photoaging. Vitamin E and C had been studied extensively . however, CoQ10, the same antioxidant was less investigated, witch was popularly utilizated in the treatment of the cardiovascular and cerebrovascular diseases. This experiment focuses on the protective effects and mechanisms of CoQ10 and result will contribute to the application of CoQ10 to prevent photoaging of the skin.Objective First of all, we wish to study the kinetics of primary cultured human skin keratinocytes following UVB irradiation at different dosages. An oxidative damage model of keratinocyte irradiated by ultraviolet B was established. Secondly, we want to investigate the possible protective effects of coenzyme Q10 (CoQ10) on human keratinocyte damaged from ultraviolet B irradiation and its mechanism.Methods Primary keratinocytes from human skin were cultured in vitro. The cultured cells were identified by morphology and immunohistochemistry. The activities of human keratinocytes following UVB irradiation at various dosages were tested by MTT method; An oxidative damage model of keratinocytes were obseveresd by invert microscope and fluorescence microscope. The apoptotic rate and proliferation index (PI) of the cell were tested by Flow Cytometer(FCM). The contents of lipidperoxidation product, malondialdehyde(MDA) and the activities of superoxide dismutase(SOD), catalase (CAT) , glutathione peroxidase (GSH-Px) in the supernatants of cells were determined by biochemical methods.Results It was found that the survival ratio of keratinocytes following UVB irradiation (UVB 10, 20mJ/cm2) increase compared with normal controls ,and contrary results occurred in cells receiving UVB irradiation (UVB 30,40,50mJ/cm2) after cells following UVB irradition were incubated for 24 hour. An oxidative damage model , apoptosis model was established at the dosage of UVB of 30 mJ/cm2. The rates of apoptosis were decreased significantly in CoQlO group (40ul and 20ul) .the cell proliferation index(PI) was increased in CoQlO group (40ul) compared with group without CoQlO. CoQlO could enhance the activities of SOD, GSH-Px and decrease the contents of MDA in the supernatants of cells.Conlusions Low dosage of UVB irradiation can Facilitate keratinocyte growth, and high dosage of UVB irradiation can inhibit it. CoQlO can inhibit the cell apoptosis and improve the cell proliferation with certain concentration. CoQlO has the protective effects on the human keratinocyte irradiated by UVB. The mechanism of effect of CoQlO may be mediated by eliminating the free radicals, by increasing the activities of SOD, GSH-Px to inhibit the oxidative damages caused by UVB.