Abstract
Purpose: :
To investigate the anti-angiogenesis capacity of Tetramethylpyrazine(TMPz) on the vascularization in chick embryo chorioalletoic membrane (CAM) and its effect on retinal neovascularization in oxygen-induced retinopathy (OIR) mice.
Methods: :
Forty-eight Fertilized chick eggs were randomly divided into 4 groups and incubated at 37 ºC with 55% humidity for 9d. Then, exposing the CAM by open a round well(r=0.5cm) on the shell. CAM were treated with Physiologic Saline (Control) and TMPz 25ug/ring (Group1) , TMPz 50ug /ring (Group2), TMPz 100ug/ring (Group3) which were topically administrated in the center of the filter ring on the CAM. Continue incubation until d13, then CAM was fixed . Vascular density was quantified by branch point counting. In the next study, Forty Neonatal C57BL6 mice were exposed to 75% oxygen from postnatal day 7 (P7) to P12. At P12, the mice were transfer to room air and treated with 100mg/Kg (Group1),200mg/Kg (Group2), 400mg/Kg TMPz (Group3) or vehicle (Control) by intraperitoneal injection once a day until P16 for 5 days. At P17, mice were sacrificed, and retinal flat-mount was prepared. To quantify the area of the retinal neovasculariztion, we stained CD31 selectively by immunocytochemistry.
Results: :
In the CAM assay, The average vessel branch points is 148.7±38.0(Control), 156.6±41.91(Group 1), 99.6±34.62(Group 2), 110.6±55.3(Group 3). Compare with Control, the vascular density of Group 2 and Group 3 decreased by 33.1% and 25.7% respectively(P<0.05). There is no difference between Control and Group 1 (P=0.283).In the OIR mouse model, The average area of NV are 2.17±0.21 mm2/eye(Control), 2.37±0.25mm2/eye(Group1), 1.87±0.16mm2/eye(Group2), 1.49±0.13 mm2/eye (Group3) respectively. Compare with the Control group, the average area of NV in Group3 and Group2 decreased 31.4%(p<0.01) and 13.9%(p=0.28). While there is no difference between Control and Group1.
Conclusions: :
TMPz can partly inhibit the angiogenesis on the CAM, but whether it is dose-dependence needs future study. And TMPz can also partly inhibit retinal neovascularization in the mouse model of oxygen-induced retinopathy with a dose dependent effect, and that administration of these agents could have clinical utility for treatment of Retinopathy of prematurity.
Keywords: retinal neovascularization