Dll4、Notch1在大鼠氧诱导性视网膜病变模型中的表达

Expression of Dll4 and Notch1 on oxygen-in duced retinopathy in rats

目的观察Dll4、Notch1在大鼠氧诱导性视网膜病变(oxygen induced retinopathy,OIR)模型中的表达情况,探讨其在视网膜新生血管形成过程中的作用。方法取70只出生5 d的SD大鼠随机分为实验组和对照组。实验组大鼠35只置于体积分数80%高氧环境7 d建立OIR模型,对照组35只大鼠置于正常空气中。两组大鼠分别于生后第12天和第17天取材,通过ADP酶视网膜铺片、HE染色视网膜切片观察实验组与对照组视网膜血管形态及新生血管生长情况,应用Western blot和RTPCR的方法检测Dll4、Notch1蛋白及其mRNA的表达水平。结果苏木精-伊红染色视网膜切片可见,实验组大鼠视网膜新生血管数量及突破内界膜的血管内皮细胞数量较对照组显著增多;对照组每眼突破内界膜的血管内皮细胞核数为0.10±0.32,实验组为32.30±4.85,两组差异有统计学意义(P=0.000)。ADP酶视网膜铺片显示,在OIR造模后12 d中,大鼠视网膜血管普遍收缩闭塞,视网膜后极部及中周部出现大片无血管区;17 d时,后极部视网膜血管扩张、迂曲,在视网膜周边部存在无血管区,在有血管区和无血管区的交界处可见新生血管簇形成。实验组Dll4、Notch1蛋白及其mRNA在造模后12 d大鼠视网膜中表达降低,而在17 d时表达增高,实验组12 d与17 d之间,以及实验组与对照组同时间点之间比较差异均有统计学意义(均为P<0.05)。结论 Dll4-Notch1信号途径在视网膜新生血管形成的过程中可能具有潜在功能。

Objective To observe DU4 and Notchl expression on oxygen-in- duced retinopathy （OIR） in rats,and to investigate effects of Dll4 and Notchl on retinal neovascularization. Methods Seventy five-day-aged SD rats were randomly and even- ly divided into experimental group and control group. 35 rats in experimental group were placed in high oxygen environment （ 80% ） for 7 days to build OIR model,and rats in control group were put in the normal air environment. Retinal vascular morphometry and angiogenesis were observed by ADP enzyme retinal preparation and retinal section with HE staining, and the expression of Dll4 and Notchl and their mRNA were tested by Western blot and RT-PCR on the 12 day-aged and 17 day-aged rats in two groups, re- spectively. Results The number of retinal new blood vessels and vascular endothelial cell beyond inner limiting membrane in rats of OIR model significantly increased seen on the retinal section with HE staining. The number of vascular endothelial nuclei be- yond inner limiting membrane of each eye in control group and experimental group was 0.10 ±0.32 and 32.30 ±4.85 ,respectively,and the difference had statistical significance （P =0.000）. ADP enzyme retinal preparation showed that in the 12 days after OIR mod- el establishment,retinal vessels in rats generally contracted and large avascular area ap- peared in posterior and medium retina. On the 17th day,posterior retinal vessel tortuous dilated;avascular area appeared around retina and new blood vessel cluster formed at the border of vascular and avascular area. The expression of Dll4 and Notchl and their mRNA decreased on the 12nd day of the model establishment, but increased on the 17th day. The differences had statistical significance （ all P 〈 0. 05 ）. Conclusion Dll4- Notchl signaling pathway may have potential function in the retinal neovascularization formation.