可见光照对培养的人视网膜色素上皮细胞凋亡的影响

目的 研究可见光照对培养的人视网膜色素上皮(retinal pigment epithelium,RPE)细胞凋亡的影响。 方法 以白色荧光灯为光源，用500 lx、(2000±500) lx及(3400±200) lx不同光照强度,按不同的光照时间(无光照、6、12、24 h)照射培养的人RPE细胞。利用终末脱氧核糖核苷酸转移酶介导的原位缺口末端标记(terminal deoxynucleotidyl transferase mediated dUTP nick end labelling, TUNEL)、荧光素标记的连接素V/碘化丙锭(Annexin V-fluorescein isothiocyanate/Propidium iodium，Annexin V-FITC/PI)双染色流式细胞测定、相差倒置显微镜等手段观察RPE细胞凋亡(分为光照后6、12、24、36 h组)。 结果 可观察到RPE细胞出现两种死亡形式，凋亡与坏死。(1)低于一定阈值(500 lx)的光照对细胞损伤较轻，细胞凋亡及坏死随光照强度的增加而增加。(2)在较短的光照时间(6 h和12 h)内，细胞死亡的增加以凋亡为主；随着光照时间的延长，细胞坏死逐渐明显。(3)随着光照后培养时间的延长，细胞凋亡明显增加(P＜0.05)。光照后6、12、24 h的损伤改变以凋亡为主，但随时间的延长，凋亡继发性坏死的增加显著。光照后36 h，细胞的坏死数显著增高(P＜0.01)。 结论 可见光超过一定照度(500 lx)可导致培养的人RPE细胞凋亡及坏死的显著增加，其损伤程度为光照强度及时间依赖性。较低光照强度及较短光照时间主要诱导细胞凋亡，反之则导致细胞坏死。 (中华眼底病杂志, 2002, 18: 227-230)

The effect of visible light on apoptosis of cultured human retinal pigment epithelium cells

Objective To observe the effect of visible light on apoptosis of cultured human retinal pigment epithelium (RPE) cells. Methods Being the light source,500lx,(2 000±500)lx and (3 400±200)lx cold white light were used. The duration of exposure was 0,6,12 and 24 hours respectively. Apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labelling, Annexin V-flunorescein isothiocyanate/Propidium iodium labelling and flow cytometry. Results Apoptosis and necrosis were found in cultured human RPE cells which were exposed to visible light.(1)A significant increase in apoptotic and necrotic percentages was consistent with a higher light intensity.(2)Apoptosis was the main response to shorter (6 h and 12 h) exposure duration,while necrosis was more pronounced correlated to the prolongation of post-exposure culture (P＜0.05),and the longer the post-exposure period was, the more apoptotic necrosis were seen.Thirty-six hours after exposure the necrotic percentages were more pronounced (P＜0.01). Conclusions Visible light (＞500 lx) increases the proportion of apoptosis and necrosis of human RPE cells in vitro.The extent is related to exposure intensity and duration. It demonstrates that the lower intensity and the shorter duration of exposure to light are, the more pronounced apoptotic percentages are observed,otherwise necrosis. (Chin J Ocul Fundus Dis, 2002, 18: 227-230)