Protective Effects Of Subretinal Transplantation Of The Bone Marrow Mesenchymal Stem Cells On Light-damaged Retina

Objective: To study the changes of the retinal tissue structure and retinal cellapoptosis in the rat model for light-damaged retina; to observe the effects ofGFP-BMSCs subretinal transplantation on light-damaged retina.Methods:1. Rat model for light-damaged retina:Sprague-Dawley rats were exposed to longtime cycle light.The rats’ eyes were removed at the point of3d,7d,10d,14dafter light exposure.Histological changes in the retina were observed byhematoxin-eosin(HE) staining.Apoptosis of retinal cells was identified by theterminal deoxynucleotidyl transferase-mediated nick end labeling(TUNEL).2. Subretinal transplantation of GFP-BMSCs:GFP-BMSCs were transplanted intothe subretinal space of light-damaged rat model.The ONL thickness,the apoptosisof retinal cells and the expression of neurotrophic factors(bFGF、BDNF) wereobserved by HE staining,TUNEL detection,immunofluorescence,real-time PCRamong the groups7days after transplantation.The groups were normal controlgroup,light damaged group,BMSCs-injected group and DMEM-injected group.Inthe BMSCs injection group,immunofluorescence and real-time PCR wereconducted to observed the migration of transplanted cells and the expression ofbFGF、BDNF at the1st、3rd、7th、14th、21th day after transplantation. Results:1. With the passage of light exposure time,progressive reduction of the outer nuclearlayer thickness was observed by HE staining.Meanwhile,progressive increase ofthe apoptotic retinal cells number was detected by TUNEL.2. GFP-BMSCs were able to migrate to the inner retina tissue after subretinaltransplantation.Delayed reduction of the ONL thickness was observed inBMSCs-injected group(P<0.05).The apoptosis in retinal cells were also inhibitedin BMSCs-injected group(P<0.05).Immunofluorescence showed four groups ofthe localization of neurotrophic factors wasn’t the same.Aftertransplantation,immunofluorescence、RT-PCR showed the expression of bFGF、BDNF and their mRNA was up-regulated(P<0.05).Within21days aftertransplantation,the expression of bFGF、BDNF and their mRNA increased firstlyand then decreased,but the expressive peak at the different time points.Conclusions:Subretinal transplantation of GFP-BMSCs exerts neuroprotective effectagainst light damaged retina.The mechanism may be as follows. The transplantedBMSCs secrete neurotrophic factors and promote retinal cells secrete neurotrophicfactors. Then the light damaged retina is restored.