Abstract
Purpose:
To determine the neuroprotetive effect of human serum albumin nanoparticles (HSA-NPs) in the glaucoma animal model by reducing the toxicity of over-expressed amyloid-β (Aβ)
Methods:
The brimonidine loaded HSA-NPs were produced by desolvation methods. The particle size distribution was determined by dynamic light scattering method and particle surface charges was evaluated by dynamic electrophoretic mobility method. Loaded amount and in vitro release of brimonidine from HSA-NPs were quantified by HPLC. The neuroprotective effect on RGCs by HSA-NPs against Aβ in vitro was determined by MTT assay. The glaucoma animal models were induced by clipping optic nerve for 60s. Aβ up-regulation in the glaucoma animal models was demonstrated by immunohistochemistry. After optic nerve injury, balance salt solution (Group I; control), free HSA-NPs (Group II) and brimonidine loaded HSA-NPs (Group III) were injected intravitreally. After 5days post injection, RGCs loss was calculated by cell count in retinal flat mount which was retrogradely labeled with rhodamine-dextran3000.
Results:
The brimonidine loaded HSA-NPs showed narrow size distribution and negatively charged surface. Size distribution of HSA-NPs was 152.78±51.11nm and zeta potential was -29.7±7.54mV. In MTT assay, the cell viability of RGCs in Aβ treated group was 51.91±7.59%, while the cell viability in Aβ and HSA-NPs treated group was 90.13±5.69% after 24h. This result supposed that HSA-NPs were capable of preventing neurodegeneration of RGCs by blocking mechanism of amyloid-β derived apoptosis. In the neuroprotection analysis in in vivo experiments, compared to the result of normal model, RGCs loss of Group I, II and III was 66.81±4.34%, 34.32±1.55% and 26.19±5.21%, respectively. RGCs loss of Group II and Group III were decreased about 2 times, compared to the result of the Group I after 5days post administration.
Conclusions:
The brimonidine loaded HSA-NPs showed high neuroprotective effect on the RGCs by not only brimonidine reaction but also HSA-NPs by mechanism interfering neurotoxic pathway of amyloid-β. Therefore, brimonidine loaded HSA-NPs capable of dual mechanism for neuroprotection synergically enhanced the neuroprotection of RGCs. And we expect that brimonidine HSA-NPs alternate previous glaucomatous drugs for enhancement of neuroprotection.
Keywords: 531 ganglion cells