AIM:To investigate the protective effects of Dendrobium officinale polysaccharide(DOP)on high glucose-induced apoptosis in retinal capillary pericytes and its potential mechanism involving mitochondrial function.METHODS:Retinal capillary pericytes were allocated into five groups: normal control(NC), high glucose(HG), and three DOP treatment groups(low, DOP-L; medium, DOP-M; high, DOP-H). Pericyte ultrastructure was analyzed using transmission electron microscopy(TEM). Apoptotic rate was quantified via Annexin V-FITC staining. Mitochondrial transmembrane potential was assessed using the JC-1 probe. Quantitative real-time polymerase chain reaction(qRT-PCR)and Western blot were employed to measure expression levels of cytochrome C(Cyt C), B-cell lymphoma 2(Bcl-2), Bcl-2-associated X protein(Bax), Caspase-9, and Caspase-3, respectively.RESULTS:Compared to the NC group, pericytes exposed to HG exhibited significant mitochondrial damage, elevated apoptotic rate, increased mRNA and protein expression of Cyt C, Bax, Caspase-9, and Caspase-3(all P<0.01), alongside a marked reduction in mitochondrial transmembrane potential and expression of Bcl-2 mRNA and protein(all P<0.01). In contrast, DOP treatment groups(DOP-M,DOP-H)dose-dependently ameliorated mitochondrial damage, reduced apoptotic rate, downregulated Cyt C, Bax, Caspase-9, and Caspase-3 expression, enhanced mitochondrial transmembrane potential, and upregulated Bcl-2 expression relative to the HG group(all P<0.05).CONCLUSION:DOP attenuates high glucose-induced apoptosis and mitochondrial injury in retinal capillary pericytes. The underlying mechanism may involve the restoration of mitochondrial transmembrane potential.