RHO and retinal degeneration: To examine whether preserved retinal sheets could become engrafted and differentiate into mature photoreceptors in severely degenerated condition, we performed a transplantation study using end-stage retinal degeneration model nude rats carrying a mutated human rhodopsin transgene (SD-Foxn1 Tg(S334ter)3Lav nude rats, RD-nude rats hereafter)54,55.