Objective      To investigate the expression of Nogo-A/B proteins in the retina of Royal college of surgeons (RCS) rats (a classic genetic animal model with hereditary retinal degeneration) and its significance.       Methods      According to the development status of retinal degeneration

the RCS-p+ (RCS rats with inherited retinal dystrophy) rats were divided into 4 groups including a P15d group

a P30d group

a P60d group and a P90d group

and RCS-rdy+p+ (RCS rats without retinal degeneration) rats of the corresponding periods were used as control groups (C15d group

C30d group

C60d group and C90d group

n=5). Immunohistochemical assay and Western blot analysis were used to detect the expression patterns of Nogo-A/B proteins in the retinal tissues of the RCS rats (RCS-p+/RCS-rdy+p+).        Results      (1) Compared with the control groups

no obvious change of the cell numbers and thickness of retina were observed in the P15d and P30d groups

except for a slight decrease of retinal ganglion cell (RGC) number. In the P60d and P90d groups

apparent structural disorder was observed in the outer nuclear layer (ONL) and inner nuclear layer (INL) of the retina. In addition

the cell number decrease was significant in the ONL and RGC layers. (2) The immunohistochemistry results showed that the positive expression of Nogo-A/B proteins was detected in each time period

and the Nogo-A/B expression upregulated along with the retinal degeneration process from P15d

mainly locating in the INL and RGC layers. The number of Nogo-A/B-positive cells was significantly greater in the RCS-p+ rats than in the RCS-rdy+p+ rats. (3) Western blot analysis showed that the protein expression of Nogo-A of the RCS-p+ rats at P15d

P30d

P60d and P90d were (0.827 37±0.212 92)

(1.110 19±0.089 99)

(1.315 52±0.028 57) and (1.268 81±0.080 42)

respectively

which were significantly different from those of the control groups (P0.05). The trend of Nogo-B2 protein expression was consistent with that of the Nogo-A protein expression

but the quantity is relatively low.       Conclusion      Nogo-A protein may be involved in the inhibition of the regeneration and repair of optic nerve in retinitis pigmentosa.