不同光照射方式对大鼠视网膜外核层厚度的影响

Effects of different ways of illumination on outer unclear layer thickness of mouse retina

目的：比较连续性光照射与间歇性光照射对大鼠视网膜的影响，探讨视网膜光损伤的发生机制。方法：Wistar大鼠，雌性，8～10wk 42只，随机分为正常对照组，连续性与间歇性损伤组，用强度为2380±5691x绿色荧光灯为致伤光源，连续光照射24h建立连续性光损伤模型；光照射3h，暗适应3h，反复8次建立间歇性光损伤模型。光照射后3，7，14d取材，石蜡包埋、HE染色，图像分析仪测量视网膜外核层厚度。结果：正常Wistar大鼠视网膜形态正常，结构层次分明，内外节排列整齐，分界清晰，内外核层排列紧密，外核层厚度为43．5±1．4μm；经过24h光照射后，各个时段均有明显的病理改变，主要表现为：内外节结构紊乱，分界不清，外核层细胞核间隙增大，外丛状层及外核层均变薄。连续性损伤后3，7，14d视网膜外核层厚度分别较正常减少13．9％，34．0％，35．8％；间歇性损伤后3，7，14d视网膜外核层厚度分别较正常减少20．6％，40．8％，47．1％。间歇组与连续组同一时间段外核层厚度相比均有显著差异。结论：间歇性光照射对视网膜损伤较连续性光照射重；视紫红质可能参与并介导了视网膜光损伤。

AIM： To compare the influence of continuous illumination and intermittent illumination on the retina of Wistar mouse, and to explore the mechanism of retina light damage. METHODS： Forty-two female Wistar mice, aged 8-10 weeks old, were randomly divided into normal group, continuous damage group and intermittent damage group. The green fluorescent lamp of 2 380 ± 5691x was used as injury light source. Continuous light damage model was established by illuminating for 24 hours continuously. Intermittent light damage model was established by illuminating for 3 hours, then being in the dark environment for 3 hours, and repeating this 8 times. At 3, 7,14 days after illumination, eyeballs were taken, embedded in paraffin, and underwent HE staining. The outer nuclear layer （ONL） thickness of retina was measured through image analyzer. RESULTS： Normal Wistar mouse has normal structure of retina. There is distinct boundary between inner segment （IS） and outer segment （OS）, and inner nuclear layer （INL） and ONL were arranged in order closely. ONL thickness is 43.5 ± 1.4μ m. After 24 hours of illumination, every damage group has obvious pathological change. Major manifestation is as follows： IS and OS structure was in disorder; the boundary was not clear; the gaps between nuclei in ONL increased; outer plexiform layer （OPL） and ONLturned thin. At 3,7,14 days after continuous illumination, the retina ONL thickness reduced 13.9%, 34.0%, 35.8% respectively compared with normal group; At 3, 7, 14 days after intermittent illumination, the retina ONL thickness reduced 20.6%, 40.8%, 47.1% respectively compared with normal group. There is significant difference of ONL thickness at the same time between intermittent damage group and continuous damage group. CONCLUSION. In the same condition of identical wavelength, identical time, and identical intensity, intermittent illumination for retinal damage is more serious than continuous illumination; rhodopsin probably participate in and mediate the retinal light damage.