蓝光诱导猪视网膜色素上皮细胞复制衰老的实验研究

目的观察蓝光对猪视网膜色素上皮（retinal pigment epithelium，RPE）细胞复制衰老过程中衰老相关-β-半乳糖苷酶（senescence associated-beta-galactosidae，SA-β—Gal）的影响。方法将第3—6代猪RPE细胞置于自制蓝光发光二极管（light emitting diode，LED）光源下，波长450～500nm，1h／d；细胞表面水平光照强度分别为（500±100）lux、（1000±200）lux、（2000±500）lux，光照时细胞水平面的温度变化为36．5—37．5℃；对照组用黑纸完全包裹培养瓶。将各组细胞消化后接种于24孔板和96孔板培养24h，进行SA-β-Gal活性的检测和MTT法检测细胞增殖情况。结果随光照强度和传代次数增加，细胞内出现蓝色颗粒的阳性细胞数目逐渐增多，SA-β-Gal活性增高，除高强度与中强度光照组、第4代和第5代之间相比差别没有统计学意义（P〉0．05）外，其余每两组之间的差异均具有统计学意义（P〈0．05）；通过MTT法检测，细胞的增殖能力随光照强度和传代次数增加而降低，除中强度与低强度光照组相比差别没有统计学意义（P〉0．05）外，其余每两组之间的差异均具有统计学意义（P〈0．05）。结论蓝光可以诱导体外培养猪RPE细胞复制衰老，并且光照强度增加可以促进细胞复制衰老。

Study of porcine retinal pigment epithelium cell replicative senescence stimulated by blue light

Objective To observe the effects of blue light on SA-β-Gal in porcine RPE ceils replicative senescence. Methods The porcine RPE cells were placed under exposure of blue light source of LED which was designed and made by us. The blue light wave ranged from 450nm to 500nm. The exposure time was one hour per day and the exposure intensity were （ 500 ± 100 ） lux, （ 1000 ± 200 ） lux, （ 2000 ± 500 ） lux respectively. The temperature of the surface of cells was between 36.5 - 37.5℃ during exposure. The control group was encapsulated by black paper during exposure. The cells from passage 3 to passage 6 were seeded into 24 or 96 well culture plate for 24h to detect beta-galactosidase activity and followed by MTr assay to detect cell proliferative activity. Results The number of positive cells with blue particles increased as the function of exposure intensity and passage times while the increased the activity of SA-β-Gal. Between different exposure intensity, every two groups have statistics significance （ P 〈 0.05 ） except for the difference between high light intensity and middle light intensity. Between different passage, every two passage have statistics significance （ P 〈 0.05 ） except for the difference between passage 4 and passage 5 . Under the same exposure intensity the cell proliferation activity decreased while the passage increased, Except for the difference between middle intensity and low intensity , every other two groups have statistics significance （ P 〈 0.05 ）. The cell proliferation activity decreased with the increased light intensity, every two passage have statistic significance （ P 〈 0. 05 ）. Conclusion Blue light can induce to the replicative senescence of porcine RPE cells cultured in vitro, and higher blue light intensity can promote the RPE replicative senescence.