Functional study of early intervention for degenerative retinopathy through hydrogel sustained release system of rhEPO

Background Retinitis pigmentosa (RP) is the most common cause of blindness in retinal disease. Long-lasting ocular administration is an effective therapy to delay the progression of RP. And hydrogel sustained release system may be an available and stable drug carrier in the treatment of RP.Method Hydrogel sustained release system was constructed as a drug carrier of recombinant human erythropoietin (rhEPO). We administered retinal degenerative (rd) mice (Pdeb rd1 / Pdeb rd1 ) via subconjunctival or retrobulbar injection at postnatal 2 weeks (PN-2w), examined the mice and tested the factors of retina at two weeks after injection. Electroretinogram (ERG) was used to examine retinal function at PN-4w, western blot and q-PCR were used to test the expression of Bax, Bcl-2, iNOS and VEGFa of retina.Result Photoreceptor apoptosis were alleviated in all rhEPO administrated groups. The retinal blood supply was improved in injection groups. Compared with placebo and blank control groups, rhEPO treatment could enhance the retinal function and delay the progression of disease. Although there was no significant difference between rhEPO hydrogel and rhEPO treated group, photoreceptor apoptosis in rhEPO hydrogel group was less than that in rhEPO group, and the retinal function was better in rhEPO hydrogel group. Moreover, different routes of administration might have little effect on treatment in this research.Conclusion Early intervention can effectively control the progression of the disease. Anti-apoptosis,neuroprotection and erythropoietin of rhEPO could be useful in the treatment of RP. Hydrogel as a long-lasting drug sustained release system was stable and available, and might become a potential drug carrier in the future.