方法：三代体外培养老年牛RPE中分别加入培养液、含200μg/mL感光细胞外节段(photoreceptor outer segment，POS)的培养液、400μg/mL POS培养液，分别于24，48h和96h用流式细胞仪(AnnexinⅤ/PI双染法)检测细胞的凋亡水平。

结果：在各个时间点，空白对照组的RPE凋亡比例极低，200μg/mL POS组24h凋亡比例(包括早期凋亡和晚期凋亡)为1.73%； 随着时间延长，凋亡比例增加明显，到96h时达到65.92%。而400μg/mL POS组24h凋亡比例为4.02%，到96h时则高达91.34%。

结论：吞噬负荷量的感光细胞外节段可以诱导体外培养老年牛RPE的凋亡，并且呈现剂量和时间依赖方式。

METHODS: The third generation of cultured aged bovine RPE cells was cultured respectively with culture medium, containing 200μg/mL photoreceptor outer segment(POS)and 400μg/mL POS. Then the apoptosis rates of RPE cells after 24, 48 and 96h were detected with flow cytometry instrument(AnnexinⅤ/PI double staining).

RESULTS: In blank control group, the apoptosis rates were very low at different time. After RPE cells were cultured with culture medium containing 200μg/mL POS for 24h, the apoptosis rate including early apoptosis and late apoptosis was 1.73%. As time going, the apoptosis rate increased rapidly and reached 65.92% after 96h. After RPE cells were cultured with culture medium containing 400μg/mL POS for 24h, the apoptosis rate was 4.02%. And it reached 91.34% significantly after 96h.

CONCLUSION: Phagocytic loads can induce the apoptosis of RPE depending the time and dose.