目的：探讨铁皮石斛多糖(DOP)对高糖诱导的视网膜毛细血管周细胞凋亡的保护作用及其线粒体途径相关机制。

方法：将大鼠视网膜毛细血管周细胞分为5组：正常组、高糖组、DOP低浓度(DOP-L)组、DOP中浓度(DOP-M)组、DOP高浓度(DOP-H)组。透射电镜观察周细胞的超微结构； AnnexinV-FITC检测周细胞凋亡率； JC-1法检测线粒体跨膜电位表达； qRT-PCR及Western blot检测细胞色素C(Cyt C)、B淋巴细胞瘤-2(Bcl-2)，Bcl-2相关X蛋白(Bax)、半胱氨酸的天冬氨酸蛋白水解酶(Caspase)-9以及Caspase-3的表达水平。

结果：与正常组相比，高糖组细胞线粒体受损，细胞凋亡率、Cyt C、Bax、Caspase-9、Caspase-3 mRNA及蛋白表达显著增加(均P<0.01)，线粒体跨膜电位、Bcl-2 mRNA及蛋白表达显著降低(均P<0.01)； 与高糖组相比，DOP-M组与DOP-H组细胞线粒体受损减少，细胞凋亡率、Cyt C、Bax 、Caspase-9 、Caspase-3 mRNA及蛋白表达均显著降低，线粒体跨膜电位、Bcl-2 mRNA及蛋白表达显著增加(均P<0.05)。

结论：DOP可抑制高糖诱导的视网膜毛细血管周细胞凋亡，减少线粒体损伤，其机制可能与线粒体跨膜电位改变有关。

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.