AIM: To identify the genes that were differentially expressed in the retina of rds mouse during the development of retinitis pigmentosa.METHODS: mRNA differential display method was used to compare and analyze mRNA samples prepared from the retina of rds mouse and normal mouse on postnatal day 25(P25). Differentially expressed fragments were cloned, sequenced and compared with GenBank database by BLASTN. Expression difference was further investigated by gene-specific primer RT-PCR.RESULTS: Obvious difference in gene expression occurred between rds mouse and normal mouse. One fragment, clone No.5, shared 91% homology with rat NADH-cytochrome b5 reductase (b5R) cDNA. Thus, it was identified as mouse b5R cDNA. Gene-specific RT-PCR confirmed that b5R mRNA level was increased in the retina of rds mouse compared with normal mouse on postnatal day 12, 25 and 37, respectively.CONCLUSION: Certain oxidative factors may up-regulate the expression of b5R resulting in large consumption of NADH and production of NAD +, through which apoptotic retinal cell death was enhanced.