关键词: 视网膜色素上皮, 创伤和损伤, 光感受器细胞, 大鼠, 近交BN, 氧化性应激, 蓝光照射

Abstract:

Objective To investigate the injury characteristics and possible mechanism of photoreceptor cell and retinal pigment epithelium cell (RPEc) by establishing a model of a retinal damage in Brown Norway (BN) rats induced by blue light illumination. Methods According to random number table method, rats were divided into the light 0 d (normal control group), the light 1, 3, 7 and 14 d groups, with 8 rats in each group. The normal control group was not exposed to light. The other groups were exposed to LED blue light source with light intensity of (1 000±100) Lux for 3 h every day for 1, 3, 7 and 14 days, and the behavior and activities of rats were observed. The amplitudes of a and b waves and latency of the maximum mixed response were recorded by electroretinogram (ERG). Fundus photography was performed. Retinal tissue was observed by HE staining. The content of reactive oxygen species (ROS) in rat retina was detected by enzyme-linked immunosorbent assay (ELISA). Results Compared with the normal control group, the response to photoacoustic stimulation was slow in the 3 d light group, the spirit was weak and the action was slower in the 7 d and 14 d light group, and the response to light and sound was slower. Retinal hemorrhagic spots were occasionally observed in the group treated with 3 days of light irradiation, pigment particles increased in the base of retinal pigment epithelium (RPEc) layer, and mild nuclear pyresis was observed in the outer nuclear layer. In the group exposed to light for 7 days, scattered punctate hemorrhagic spots and yellow-white punctate particles were observed in the retina, and retinal veins were tortuous and dilated. After 14 days of light exposure, a large amount of yellow-white spot-like exudation was observed in retina. The retinal arteries were copper or even silver wire, and retinal veins were tortuous and dilated. The inner segment (IS)/outer segment (OS) of retinal photoreceptors were disordered in the 7 and 14 day light groups, the nucleus of outer nuclear layer shrank, and pigment particles were deposited at the base of RPEc layer. Compared with the normal group, the retina of rats became thinner in the 3, 7 and 14 day light groups (P<0.05). The latency of ERG b wave was gradually prolonged, the amplitudes of a wave and b wave were gradually decreased, and retinal tissue ROS was gradually increased in the groups 3, 7 and 14 d of light exposure (P<0.05). Conclusion Continuous exposure of blue light to BN rats can produce oxidative stress response, resulting in chronic retinal light damage, and with the extension of exposure time, the retinal light damage is more serious.

Key words: retinal pigment epithelium, wounds and injuries, photoreceptor cells, rats, inbred BN, oxidative stress, blue light illumination