Protective effect of astragalus polysaccharide against H_2O_2-induced oxidative damage on rat retinal ganglion cells

OBJECTIVE To observe the protective effect of astragalus polysaccharide(APS) against H2O2-induced oxidative damage on rat retinal ganglion cells(RGC). METHODS Cultured RGC-5 cells were divided randomly into 4 groups,including normal control group(Group A), negative control group(Group B), H2O2 injury group(Group C) and H2O2+ APS group(Group D). Group A received no treatment, Group B was treated with 1 000μg/ml APS, Group C was treated with 100 μmol/L H2O2, Group D was treated with different concentrations of APS(1 000 μg/ml, 500 μg/ml, 250 μg/ml) and then treated with 100 μmol/L H2O2. The cellular morphology was observed by inverted phase contrast microscope; the cell viability was measured using MTT assay and apoptosis was evaluated using DAPI staining; the cell proliferation was dynamically monitored using the real-time cell electronic sensing(RT-CES) system. RESULTS Normal RGC-5 cells were spindle or polygonal,cell borders were clearly and had short axons. Cells in Group C were sparse, shrinkage and the axons were shorter than normal cells. MTT assay: The cell viability in Group D was higher than Group C, and the difference was significant(P0.01). DAPI stain-ing revealed that characteristic apoptotic changes,such as chromatin condensation,convoluted nuclei with cavitations, fragmentation of the nucleus and apoptotic bodies appeared in RGC-5 cells in Group C. There was almost no evidence of apoptosis in Group D. RT-CES:Cell growth in Group C was suppressed, while other groups has normal cell growth curve. CONCLUSIONSAPS had apparent inhibitive effect on RGC apoptosis, which might provide some experimental basis for astragalus in treating diabetic retinopathy.