Реферат
BACKGROUND: Foreign studies have demonstrated that the blue light at 470 nm inhibits melatonin secretion and displays the most obvious biorhythm regulation. To date, light-emitting diode (LED) applied in regulating biorhythm remains poorly explored. OBJECTIVE: To explore whether a certain intensity of LED (blue) light could induce retinal injury in rats. DESIGN, TIME AND SETTING: Randomized, controlled animal experiment was performed at the Animal Laboratory of Peking University Third Hospital between May 2007 and April 2008. MATERIALS: A total of 32 SD rats and 16 BN rats were provided by Animal Department of Peking University Third Hospital. METHODS: A total of 16 SD and 16 BN rats were respectively randomly divided into test and control groups. Test group rats were placed in light boxes which were controlled by blue LED (wavelength 470 nm) at a intensity of 300-350μW/cm2, 4 hours everyday for 3 days. The remaining SD rats were placed in light box which was controlled by blue LED (wavelength 470 nm) at a intensity of 120-150μW/cm2, 4 hours everyday for 3 days. The control rats were not treated. MAIN OUTCOME MEASURES: At the second day after light irradiation, the rats of all groups were sacrificed and both eyeballs were harvested. The frozen sections were subjected to hematoxylin-eosin staining to observe changes of rat retina. RESULTS: A total of 48 rats were included in final analysis. The retina of SD rats became thinning and disorderly arranged following blue LED irradiation at density of 300-350μW/cm2, but the retina of BN rat remained unchanged similar to control group. After blue LED irradiation at density of 120-150μW/cm2, the retina of SD rat remained unchanged similar to control group. CONCLUSION: Blue LED light source irradiation at a intensity of 300-350μW/cm2 is safe to pigment-protected retina, and at a intensity of 120-150μW/cm2 does not injury retina of different races of rats.