Background/aims: To investigate the correlation between the clinical course and gene expression pattern in murine oxygen-induced retinopathy (OIR), a commonly used model of retinopathy of prematurity (ROP).
Methods: OIR was induced in C57BL/6N mice by placing postnatal day 7 (P7) pups in 75% oxygen for 5 days. The clinical course of the OIR was evaluated on retinal flat-mounts after FITC-conjugated dextran perfusion from P12 to P21. The expression values of 94 genes, selected by microarray analyses, were determined daily from P12 through P21 by RT-PCR with TaqMan® low-density array (TLDA) and analyzed by hierarchical clustering.
Results: TLDA cluster analyses showed a homology of gene expression pattern between P12 and P13 and between P16 and P17. Many genes associated with inflammation were up-regulated on P12 and P13 when the degree of both central avascular area and central vasoconstriction were maximal, and the up-regulation of the genes continued to P21. At P16 and P17 when extraretinal neovascularization became most noticeable, several genes associated with angiogenesis, e.g., vascular endothelial growth factor-A and angiopoietin-2, were most up-regulated.
Conclusion: The gene expression pattern was well-correlated with the clinical appearance in murine OIR. These findings should contribute to the understanding of the pathological conditions in ROP.