Vascular endothelial growth factor-C increases lymphatic vessels in the conjunctiva and maintains low intraocular pressure after trabeculectomy in rabbits

The aim of this study is to determine the effect of Vascular Endothelial Growth Factor-C (VEGF-C) in stimulating the growth of functional lymphatic vessels of postoperative conjunctival filtration blebs in rabbits. Twelve New Zealand Red Eye rabbits were allocated to four treatment groups, each receiving an injection of recombinant VEGF-C at doses of 0 μg (control), 1 μg, 3 μg, and 10 μg following trabeculectomy surgery. The effects of the VEGF-C injection on lymphatic vessels were analyzed using FLT4 fluorescence immunostaining and trypan blue filling techniques. Additionally, vascular vessels were examined using CD31 immunostaining, and post-surgical intraocular pressure (IOP) was compared across the treatment groups. Lymphatic vessels in treatment groups exhibited higher mean values of 11.7, 12.7, and 19.0 in groups treated with 1 μg, 3 μg, and 10 μg of VEGF-C, respectively, compared to a mean value of 5.3 in the control group (p = 0.00). Blood vessel count revealed using CD31 did not indicate any increase in vascular vessels between the groups. Intraocular pressure (IOP) levels ten days after trabeculectomy were significantly lower in the 3 μg and 10 μg treatment groups (7.00 mmHg) compared to 10.33 mmHg in the control group (p = 0.047). The study demonstrates that trabeculectomy augmented with VEGF-C injection in rabbits results in an increased lymphatic vessel count in the conjunctiva and a decrease in IOP levels on the tenth post-operative day. These findings suggest that VEGF-C may be a potential adjuvant agent for enhancing the efficacy of trabeculectomy.