VEGFR-1和VEGFR-2在氧诱导视网膜病变小鼠视网膜中表达的变化

Expressions of VEGFR-1 and VEGFR-2 in mouse retinas with oxygen-induced retinopathy

背景 早产儿视网膜病变（ROP）是氧动力学异常导致严重视网膜血管病变的致盲眼病.血管内皮生长因子（VEGF）在ROP发病机制中发挥重要作用,但VEGF受体（VEGFR）在ROP发病中的作用研究较少. 目的 研究不同鼠龄氧诱导视网膜病变（OIR）小鼠视网膜中VEGFR-1和VEGFR-2的表达变化.方法 将60只SPF级出生后7 d（P7）的C57BL/6J小鼠与哺乳母鼠一起在体积分数（75＆#177;2）％O2条件下饲养5d,建立OIR小鼠模型（OIR组）,以60只正常环境饲养的同品系同龄小鼠作为正常对照组.分别于P8、P11、P12、P13、P14、P18鼠龄时摘取2个组小鼠双侧眼球,制备视网膜切片,采用苏木精-伊红染色法检测小鼠视网膜血管的发育情况;采用实时荧光定量PCR法检测不同鼠龄小鼠视网膜中VEGFR-1和VEGFR-2 mRNA的相对表达水平;采用免疫组织化学法观察小鼠视网膜中VEGFR-1和VEGFR-2蛋白的表达.结果 组织病理学结果显示,OIR组P13、P14、P18小鼠有较多的血管内皮细胞核突破内界膜,光学显微镜下内界膜下的细胞增生,排列紊乱,视网膜表面或视网膜前有新生血管芽,但正常对照组各鼠龄小鼠视网膜结构正常.OIR组P12、P13、P14和P18小鼠视网膜中VEGFR-1 mRNA的平均相对表达水明显高于正常对照组,差异均有统计学意义（P=0.046、0.000、0.000、0.042）;OIR组P8、P11、P12、P13、P14和P18小鼠视网膜中VEGFR-2mRNA的平均相对表达水平明显高于正常对照组,差异均有统计学意义（均P＜O.01）.两个组间P8、P11、P12、P13、P14、P18小鼠视网膜中VEGFR-1蛋白阳性表达强度的差异均无统计学意义（M=50.00、36.00、41.00、31.00、28.00、36.00,均P＞0.05）;正常对照组与OIR组间P8和P11小鼠视网膜中VEGFR-2蛋白阳性反应强度的差异无统计学意义（均P＞0.05）,正常对照组P12、P13小鼠视网膜中VEGFR-2蛋白的表达减弱,但OIR组同鼠龄小鼠视网膜中VEGFR-2蛋白的表达增强,2组间差异均有统计学意义（均P＜0.01）;2个组P14小鼠视网膜中VEGFR-2蛋白表达均明显增强,但OIR组的表达强度仍显著高于正常对照组,差异有统计学意义（P＜0.01）.正常对照组P18小鼠视网膜中VEGFR-2蛋白表达减弱,OIR组VEGFR-2表达强度达峰（M=20.11,P＜0.01）. 结论 VEGFR参与OIR小鼠视网膜新生血管的形成,VEGFR-2的促新生血管新生作用强于VEGFR-1.

Background Retinopathy of prematurity （ROP） causes blindness due to retinal vasculopathy caused by abnormal oxygen dynamics.Studies have clarified the pivotal role of vascular endothelial growth factor （VEGF） in the development of ROP,while the studies on the role of VEGF receptor （VEGFR） in ROP are fewer.Objective This study was to evaluate the relationship between the expressions of VEGFR-1 and VEGFR-2 in retina and post-birth time in the mice with oxygen-induced retinopathy （OIR）.Methods Sixty 7-day-old （P7） SPF C57BL/6J mice together with lactating female mice were fed in the environment with （75＆#177;2）% oxygen concentration for 5 days and then returned to normal air to establish OIR models,and other 60 matched mice were kept in normal air environment as the control group.At P8,P11,P12,P13,P14,and P17,both eyes of each mouse were enucleated to prepare the retinal sections.Retinal blood vessels were examined by hematoxylin and eosin stain under the light microscope.Real-time fluorescence quantitative PCR and immunohistochemistry were used to detect the expressions of VEGFR1 mRNA and VEGFR2 mRNA and their proteins in mouse retinas,respectively.The use and care of the animals complied with the Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results Many vascular endothelial cell nucleus broke through the internal limiting membrane were seen with disorganized cell proliferation under the internal limiting membrane and retinal neovascularization bud in the P13,P14 and P18 mice in the OIR group,but no similar manifestation was found in the mice of the normal control group.The relative expression values of VEGFR-1 mRNA in retinas were significantly higher only in P12,P13,P14 and P18 mice in the OIR group than those in the normal control group （P=0.046,0.000,0.000,0.042）,but the expression values of VEGFR-2 mRNA were all increased in the retinas of P8,P11,P12,P13,P14 and P18 mice in the OIR group,showing significant differences in comparison with the normal control group （all at P=0.000）.No considerable difference was found in the expression level of VEGFR-1 protein in P8,P11,P12,P13,P14 and P18 mice between the two groups （M=50.00,36.00,41.00,31.00,28.00,36.00,all at P〉 0.05）.The expression levels of VEGFR-2 protein in retinas of P8 and P11 were close between the two groups （all at P〉0.05）.Gradually attenuated expressions were seen in VEGFR-2 protein in P12,P13 mice of the normal control group,however,the expressions were enhanced in the OIR group,with significant differences between the two groups （all at P〈0.01）.Enhanced expressions of VEGFR-2 protein were found in P14 mice in both groups,but stronger expressions were in the OIR group （P〈0.01）.The positive response of the expression of VEGFR-2 protein was weaker in P18 mice in the normal control group but peaked in the OIR group,showing significant difference between them （M=20.11,P〈0.01）.Conclusions VEGFR participates in the neovascularization of OIR mouse,and the effect of VEGFR-2 is stronger than that of VEGFR-1 in the development of OIR neovascularization.