Study On Some Natural Productions' Protection And Repair Effects On Human Cells From Ultraviolet Irradiation By Cell Model In Vitro

The UV spectrum can be divided into three groups: UVA (320 to 400nm), UVB (280 to 320nm) and UVC (200 to 280nm). The damage of ultraviolet radiation to human is rising because of destroying to ozone layer. In present, the sunscreens in market are mostly made with organic compounds and mineral. The side effects of these compounds on human body have been identified and there is no uniform standard to appraise these sunscreens. The purpose of this research was to build up cell model in vitro to estimate biologic effect of the sunscreens, screen out natural productions from the plant species that can provide significant protection from UV irradiation, investigate the damage and its mechanisms induced by UV with different wavelengths, understand the function of natural productions on fibroblasts in vitro in defending UV irradiation and repairing damage following exposure to UV irradiation. Results were shown as following:1. A group of cultured normal human skin-derived fibroblasts was used as the cell model in vitro, and the relationship between the proliferation of fibroblasts and the different doses of UVC and UVA irradiation with the methods of MTT colorimetry and LDH release were discussed. It was showed that low intensity UVC and UVA could promote fibroblasts proliferation and high intensity UVC and UVA could damage fibroblasts; and that UVC 0.15 J/cm2, UVA 10 J/cm2 was the dosage of half fibroblasts death respectively..2. Comparing the death degree and mode of fibroblasts after UVA and UVC irradiation, it was suggested that UVC irradiation could cause fibroblasts necrosis and UVA caused fibroblasts apoptosis, and assured that 72 hours after UVC irradiation and 24 hours after UVA irradiation was the optimized time to detect fibroblasts respectively.3. Scutellaria baicalensis georgi extract, aloe extract, green tea extract, hawk-tea extract and astragalus membranaceus injection were effective researching objects because all of them hadn't significant inhibitory effect on fibroblasts growth except of astragalus membranaceus injection that had significant effect on promoting fibroblasts proliferation.4. This study showed that scutellaria baicalensis georgi extract, astragalus membranaceus injection, green tea extract and hawk-tea extract could repair the damage induced by UVC irradiation while aloe extract could not. Furthermore, astragalus membranaceus injection had better repair effect than scutellaria baicalensis georgi extract and there were no statistically significant differences between green tea extract and hawk-tea extract. Meanwhile, green tea extract and hawk-tea extract had effect on enhancing resistance of fibroblasts against UVC irradiation damage while scutellaria baicalensis georgi extract, astragalus membranaceus injection and aloe extract could not.5. It was found that scutellaria baicalensis georgi extract, green tea extract and hawk-tea extract could repair the damage induced by UVA irradiation with dosedependence while astragalus membranaceus injection could not. Scutellaria baicalensis georgi extract was slightly better than tea extracts of the same concentration and there were no statistically significant differences between green tea extract and hawk-tea extract.Meanwhile, scutellaria baicalensis georgi extract had a strong protecting effect on fibroblasts against UVA damage with dose dependence and Smg/ml scutellaria baicalensis georgi extract could protect 90% fibroblasts from UVA damage. Green tea extract and hawk-tea extract also had strong protecting effect on fibroblasts against UVA irradiation with dose dependence. There were no significant differences between the two kinds of tea extracts in a high concentration (5mg/ml). However, when they were in low concentration(2.5mg/ml and 1.25mg/ml), green tea extract had a slight higher ability than hawk-tea extract in protecting fibroblasts from UVA damage. Scutellaria baicalensis georgi extract could protect more fibroblasts from UVA damage than the two kinds of tea extracts.6. Analyzing var...