PDE6B and retinal degeneration: Given that intravitreal injections of PEDF protein, 17-mer or H105A peptides elevate anti-apoptotic BCL-2 and attenuate pro-apoptotic BAX levels in photoreceptors of retinal degeneration models such as the rd1 mouse and RCS rat30,44, we hypothesized that these peptides delivered via eye drops would similarly regulate BCL-2 and BAX proteins to prevent cell death in rd10 and rd10/Serpinf1-/- retinas.