The involvement of NK1 and Y2 receptor in the development of laser-induced CNVs in C57Bl/6N mice.

Purpose: to explore whether the NK1 and Y2 receptors are involved in the pathogenesis of laser-induced CNV (choroidal neovascularization) in C57Bl/6N mice.

Methods: CNV was induced by laser damage of Bruch's membrane and the CNV volume was determined by OCT and/or flatmount preparation. First, the development of the CNV volume over time was evaluated. Second, the CNV development in NK1- and Y2 KO mice was analyzed. Third, the effect on the development as well as the regression of CNV by intravitreal injections of the NK1 antagonist SR140333 and the Y2 antagonist BIIEO246 separately and each in combination with Eylea, was investigated. Furthermore, flatmount CNV volume measurements were correlated to volumes obtained by the in vivo OCT technique.

Results: CNV volume peak was observed at day 4 after laser treatment. Compared to wild type mice, NK1 and Y2 KO mice showed significantly smaller CNV volumes. Eylea and the Y2 antagonist significantly reduced the volume of the developing CNV. In contrast to Eylea there was no effect of either antagonist on the regression of CNV, additionally no additive effect upon combined Eylea/antagonist treatment was observed. There was a strong positive correlation between CNV volumes obtained by OCT and flatmount.

Conclusion: NK1 and Y2 receptors mediate the development of laser-induced CNVs in mice. They seem to play an important role at the developmental stage of CNVs, whereas VEGF via VEGF receptor may be an important mediator throughout the CNV existence. In vivo OCT correlates with flatmount CNV volume, representing a useful tool for in vivo evaluations of CNV over time.