(A–C) The qRT-PCR assay showed that the mRNA levels of Caspase-3, CHOP, and Bax in the INas administered group were significantly down-regulated compared with the MNU group. The mRNA level of Caspase-3, CHOP, and Bax in the INas administered group was also significantly lower than that in the IVen administered group. (D) In the INas administered group, the mRNA level of Bcl-2 was significantly higher compared with the MNU group, suggesting that the anti-apoptotic mechanism should be responsible for the EPO mediated protection. (E) The retinal MDA concentration in the INas administered group was significantly lower than that in the MNU group. (F) The expression level of SOD in the INas administered group was significantly up-regulated compared with the MNU group, suggesting that the INas delivery of EPO could alter the oxidation status in the degenerative retina. (G) The Mn-SOD level in the IVen administered group was significantly higher than that in the MNU group. Meanwhile, the Mn-SOD level in the IVen administered group was significantly lower than that in the INas administered group (ANOVA analysis followed by Bonferroni's post-hoc analysis was performed,*p < .05, #p < .01, for differences between groups; n = 10).