[The expression and function of annexin A2 in the course of retinal angiogenesis of mouse]

To study the production and the role of annexin A2 (ANXA2) in the process of retinal neovascularization of mouse.

Experimental study. C57BL/6J mice were classified into four groups:normal group (80 mice), oxygen induced retinopathy (OIR) mock group (80 mice) , siANXA2 group (transfected with siRNA target ANXA2) (50 mice) , and siANXA2_M group (50 mice) .Stretched preparation of retina after angiography was used to observe the morphology change of retinal neovascularization from 12 to 30 days after birth in normal group and OIR mock group, and real-time PCR was used to test the expression of ANXA2 in these days. On 17 days old, the mRNA and protein production of vascular endothelial growth factor (VEGF)-α, matrix metalloproteinase (MMP)-2, MMP-9, and tissue inhibitor of metalloproteinase (TIMP)-2 in 4 groups were assessed by real-time PCR and Western blot. The results of all factors among four groups were analyzed by one way ANOVA and SNK-q test.

The retinal neovascularization of siANXA2 group in 17 days old was more regular than that in OIR mock group. The production of ANXA2 in mouse retina was associated with the stage of retinal neovascularization. The expression of ANXA2 was in high level when neovessels grew and in low level when neovessels stopped growing. The mRNA expressions of ANXA2,VEGF-α, MMP-2, MMP-9 and TIMP-2 showed statistical difference among 4 groups (F = 8.122-74.009, P < 0.05) . Significant statistics difference was found in multiple comparison:the expressions of VEGF-α (0.22 ± 0.04), MMP-2 (11.08 ± 1.28), MMP-9 (4.64 ± 0.38) in OIR mock group were significantly higher than that in normal group (0.16 ± 0.02, 2.18 ± 1.39, 1.17 ± 0.25) (SNK-q test: P < 0.01).In siANXA2 group, the productions of VEGF-α (0.02 ± 0.01), MMP-2 (2.21 ± 0.42) , MMP-9 (1.33 ± 0.10) were significantly lower than that in OIR mock group (SNK-q test: P < 0.01). The mRNA expression of TIMP-2 (0.59 ± 0.15) in OIR mock group was significantly lower than that in normal group (1.35 ± 0.01) (SNK-q test: P < 0.05). In siANXA2 group, the production of TIMP-2 was higher than that in OIR mock group (SNK-q test: P < 0.05). The results of Western blot were similar to that in real-time PCR.

ANXA2 is overexpressed in oxygen-induced retinal neovascularization in a mouse model. The overexpression of ANXA2 may affect the expression of proangiogenic factors. ANXA2 may involve in the development of the retinal neovascularization. The production of ANXA2 may be inhibited by siRNA. ANXA2 maybe a new target for inhibition of retinal neovascularization.