Abstract
Abstract: :
Purpose: Previous studies have shown that matrix metalloproteinase-2 (MMP-2) is involved in experimental, inflammation-associated, choroidal neovascularization (Berglin et al. IOVS, in press). To investigate whether MMP-2 is also involved in experimental, ischemia-associated, retinal neovascularization we have studied neovascularization in a model for retinopathy of prematurity (ROP) in MMP-2 knock out mice. Methods: Ischemic retinopathy was produced in 14 MMP-2 knock out mice and 20 control mice. 7-day-old pups were exposed to 75% 02 for 5 days and then returned to normoxic conditions for an additional 5 days. Retinal neovascularization was maximal at P17 when mice were sacrified and eyes were enucleated and fixed. Serial paraffin embedded sections were stained with hematoxylin-eosin and neovascularization was quantified by counting the number of retinal vascular cell nuclei internal to the inner limiting membrane. Retinal neovascularization was also visualized on retinal flat-mounts from animals perfused with FITC-dextran. Results: In the MMP-2 knock out mice group the median number of nuclei on the vitreous side of ILM was 26,0 (range 16,4 - 49,1) compared to 35,8 (range13,6 - 67,4) in the control mice group. Retinal neovascularization was non-significantly reduced in the MMP-2 knock out mice group. Retinal flatmounts appeared similar in the two groups. Conclusions: The weak and statistically non-significant reduction in retinal neovascularization in MMP-2 knock out mice compared to normal mice suggests that MMP-2 may be less important in ischemia-associated neovascularization.
Keywords: retinal neovascularization • neovascularization • molecular biology