FIGURE 5.
Elevated MMP and subsequent decreased expression of CD44 and neurocan correlate with enhanced photoreceptor integration in the MRL mouse retina. Abutting retinal explants were performed in which GFP-positive photoreceptor sheets isolated from adult mice were transplanted on top of BL6, rd1, or MRL mouse retinas. Explants were cultured in serum-free neurobasal media for 7 days and subsequently fixed, cryoprotected, sectioned, and analyzed using confocal microscopy for GFP expression and subsequent cell counting. Although minimal photoreceptor integration was detected in abutting Bl6 (A, D) and rd1 (B, D) cultures, indicated by a lack of GFP-positive cells in the host tissue, increased integration of GFP-positive photoreceptor cells was detected in the MRL mouse retinas (C, D), indicated by numerous GFP-positive cells that have migrated to the host tissue (n = 12). Significance was tested using one-way ANOVA with Tukey testing for post hoc comparisons. **P < 0.001. Scale bar = 20 μm.