METHODS: BRVO model rats were induced by photochemistry induction and randomly divided into BRVO model group and TA(1, 7, 21)d groups; at the same time, blank control group was set for comparison. The intraocular pressure of rats was measured by ophthalmotonometer; the condition of rat fundus was observed fluorescein fundus color photography(FFA)and optical coherence tomography(OCT); retinal angiogenesis related factors vascular endothelial growth factor(VEGF)and vascular endothelial growth factor receptor 2(VEGFR2), the protein expressions of Notch pathway important factors Notch 1, Jagged 1 and DLL4 were detected in rat retina by Western blotting(WB).

RESULTS: In the normal control group, the fundus vessels were arranged neatly and in a clear state. In the BRVO model group, edema appeared in the fundus, the retina turned white, the arrangement of blood vessels was disordered, the optic disc pit was disappeared, retinal vessels were in the state of vasoconstriction. In TA 1, 7 and 21d groups, edema gradually decreased, blood vessels expansion and bending gradually slowed down, and the optic disc pit was restored. Compared with the blank control group, the intraocular pressure of BRVO model group increased, the thickness of the retina increased at the injured site and 250μm far from injured site, the protein expressions of VEGF, VEGFR2, Notch1 and Jagged1 increased, the protein expression of DLL4 protein was decreased(P<0.05). Compared with the BRVO model group, in TA 1d group, the retinal thickness decreased at 250μm far from injured site, the protein expressions of VEGFR2, Notch1 and Jagged1 decreased, the protein expression of DLL4 protein increased; in TA 7d group, the retinal thickness was decreased at the injured site and 250μm far from injured site, the protein expressions of VEGFR2, Notch1 and Jagged1 decreased, the protein expression of DLL4 protein increased; the intraocular pressure of TA 21d group decreased, the thickness of the retina decreased at the injured site and 250μm far from injured site, the protein expressions of VEGF, VEGF R2, Notch1 and Jagged1 decreased, the protein expression of DLL4 protein increased(P<0.05).

CONCLUSION: Vitreous injection of TA may inhibit angiogenesis by regulating Notch pathway to inhibit the activation of VEGF, thus achieving the retinal protection in BRVO rats.