Stem cell therapy is a promising therapeutic approach for
retinal degeneration (RD). Our study investigated the effects of human adipose
derived stem cell (hADSCs) on Royal College of Surgeons (RCS) rats.
Methods: Green fluorescent protein (GFP)-labeled hADSCs were transplanted
subretinally into RCS rats at postnatal (PN) 21 days to explore potential therapeutic
effects, while adeno-associated viral vector (AAV2)-vascular endothelial growth
factor (VEGF) and siVEGF-hADSCs were used to aid the mechanistic dissections.
Visual function was evaluated by Electroretinogram (ERG) recording. Potential
transdifferentiations were examined by Immunofluorescence (IF) and gene
expressions were analyzed by quantitative reverse transcription-polymerase chain
reaction (qRT-PCR). Apoptotic retinal cells were detected by Terminal Deoxynucleotidyl Transferase
dUTP Nick End Labeling (TUNEL) assay and the cytokines secreted by hADSCs were measured by
Enzyme-linked Immunosorbent Assay (ELISA).
Results: The visual function of RCS rats began to decrease one week after their eyes opened at PN
week 3 and almost lost in PN 5 weeks, accompanied by the loss of retinal outer nuclear layer (ONL).
Subretinal transplantation of hADSCs significantly improved the visual function 2 weeks after the
transplantation and such therapeutic effect persisted up to 8 weeks after the treatment (PN 11 weeks),
with 3-4 rows of photoreceptors remained in the ONL and reduced apoptosis. Consistent with these
phenotypic changes, the gene expression of rod photoreceptor markers Rhodopsin (Rho), Crx and
Opsin (Opn1) in RCS rats showed obvious decreasing trends over time after PN 3 weeks, but were
elevated with hADSC treatment. hADSC transplantation also repressed the expressions of Bax, Bak
and Caspase 3, but not the expression of anti-apoptotic genes, including Bcl-2 and Bcl-XL. Finally,
substantial VEGF, hepatocyte growth factor (HGF) and pigment epithelium-derived factor (PEDF)
secretions from hADSCs were detected, while endogenous Vegf expression level decreased over time
in RCS rats. The treatment of AAV2-VEGF showed comparable therapeutic effects as hADSCs but
siRNA knockdown of VEGF in hADSCs essentially abolished the therapeutic effects.
Conclusions: Subretinal transplantation of hADSCs in RCS rats effectively delayed the retinal
degeneration, enhanced the retinal cell survival and improved the visual function. Mechanistically this
was mainly due to hADSC dependent anti-apoptotic and neuroprotective effects through its secretion of
growth and neurotrophic factors including VEGF. Clinical application of hADSCs merits further