Impact of neurotrophic factors combination therapy on retinitis pigmentosa

Objective We aimed to determine the location of neurotrophic receptors tropomyosin receptor kinase (Trk)B, TrkC, and ciliary neurotrophic factor receptor (CNTFR)alpha in the retina of retinal degeneration (rd) mice and to explore the dynamic changes of B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X-protein (Bax), and microtubule-associated protein light chain 3 (LC3) expression and ultrastructure in the retina of rd mice intravitreally injected with neurotrophic factors. Methods Rd mice aged 2 and 3 weeks post-natally (PN) received intravitreal injections of neurotrophic factors. Two weeks later, their retinas were harvested for the detection of Bax, Bcl-2, and LC3 mRNA and protein expression. Results TrkB and TrkC expression levels were lower at 3 weeks PN compared with 0, 1, and 2 weeks PN, but CNTFR alpha expression was still detected in certain layers. The three receptors were expressed in different retinal layers at the same timepoint. Bax expression was downregulated in, rhBDNF + rhCNTF, rhBDNF + rhNT-3, groups 2 weeks after intravitreal injection; Bcl-2 expression was upregulated in the rhBDNF + rhCNTF + rhNT-3 group at PN-4w; and LC3 expression was upregulated in rhBDNF + rhCNTF + rhNT-3 groups. Conclusions The combined use of neurotrophic factors had a more significant effect on Bax, Bcl-2, and LC3 expression than the same factors used alone.