Light-induced Damages in the Retina of Juvenile Emperor Red Snapper (Lutjanus sebae)

• Main Authors: yahuikang, 康雅惠
• Other Authors: HUANG PAO KUEI
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/20425197636376403099

碩士 === 國立海洋大學 === 環境生物與漁業科學學系 === 91 === The purpose of this study is to understand the light induced damages in retina of juvenile emperor red snapper (Lutjanus sebae). The fishes were exposed to different light intensity (visible light: 0, 300, 3x104 lux, 6x104 lux; UV light: 254 nm, 365 nm) and duration (1 and 3 hours) to investigate those influences on each cell layer of retina and retinomotor response. The retina of juvenile emperor red snapper (Lutjanus sebae) was composed of 8 cell layers as in those of most teleost species. After exposed to visible and UV light, the damages of retina could be shown by those abnormal morphological features in rod cells, cone cells, inner nuclear layer and ganglion cells. In rod cells, only mitochondrial swelling could be identified in inner segments of abnormal ones. In cone cells, those abnormal morphological features could be identifed and used to class the damages of cone cells as 4 levels (1°,2°,3°,4°), which showed the injury of the outer segment (1°), the loss of the outer segment (2°), the irregular shape of the inner segment (3°), the disappearance of the cone cell (4°), respectively. In the inner nuclear layer, the damages also could be classed as 4 levels (1°,2°,3°,4°), which showed the condensation of chromatin (1°), the migration of chromatin (2°), disruption of nuclei disruption (3°), the disappearance of nuclei disappearance (4°), respectively. In ganglion cells, vacuolization of cell could be identified. After exposed to 3x104 lux for 1and 3 hours, there were no significant differences (ANOVA, p＞0.01) on the damage ratio in both rod cell groups and ganglion cell groups. After exposed to 3x104 and 6x104 lux for 3 hours, there were significantly difference (ANOVA, p＜0.01) on the damage ratio of the rod cells groups and ganglion cells groups. Therefore, it might suggest that the light-induced damage in the retina was mainly determined by light intensity. The retinomotor response of retina under the dark and light-adaptation was 24.8±3% and 85.8±2.0%, which was significantly different (t-test, p＜0.01). After exposed to 6x104 lux for 1 hour, retinomotor response was 84.9±3.6%. Dark-adaptation after exposed at 6x104 lux for 1 hour, the retinomotor response was 17.9±0.3%. Light-adaptation after exposed to 6x104 lux for 1 hour and then removed to dark-adaptation, retinomotor response was 62.2±5.6%. After exposed to UV (365 nm) for 1 hour, retinomotor response was 84.9±2.9%. Dark-adaptation after exposed at UV (365 nm) for 1 hour, retinomotor response was 19.9±2.0%. Light-adaptation after exposed to UV (365 nm) for 1 hour and then removed to dark-adaptation, retinomotor response was 68.4±4.7%. Because all cell layers of retina participate in the transmission of the visual signal, those light-induced damages in them must block the signal pathway from retina to the central nervous system (CNS) that affect the visual ability. Also, the decline in retinomotor response might suggest that the visual ability should be affected by light-induced damages in the retina.