Oxidative stress due to hyperglycemia damages the functions of retinal pigment epithelial (RPE) cells and is a major risk factor for diabetic retinopathy (DR). Paeoniflorin is a monoterpenoid glycoside found in the roots of Paeonia lactiflora Pall and has been reported to have a variety of health benefits. However, the mechanisms underlying its therapeutic effects on high glucose (HG)-induced oxidative damage in RPE cells are not fully understood. In this study, we investigated the protective effect of paeoniflorin against HG-induced oxidative damage in cultured human RPE ARPE-19 cells, an in vitro model of hyperglycemia. Pretreatment with paeoniflorin markedly reduced HG-induced cytotoxicity and DNA damage. Paeoniflorin inhibited HG-induced apoptosis by suppressing activation of the caspase cascade, and this suppression was associated with the blockade of cytochrome c release to cytoplasm by maintaining mitochondrial membrane stability. In addition, paeoniflorin suppressed the HG-induced production of reactive oxygen species (ROS), increased the phosphorylation of nuclear factor erythroid 2-related factor 2 (Nrf2), a key redox regulator, and the expression of its downstream factor heme oxygenase-1 (HO-1). On the other hand, zinc protoporphyrin (ZnPP), an inhibitor of HO-1, abolished the protective effect of paeoniflorin against ROS production in HG-treated cells. Furthermore, ZnPP reversed the protective effects of paeoniflorin against HG-induced cellular damage and induced mitochondrial damage, DNA injury, and apoptosis in paeoniflorin-treated cells. These results suggest that paeoniflorin protects RPE cells from HG-mediated oxidative stress-induced cytotoxicity by activating Nrf2/HO-1 signaling and highlight the potential therapeutic use of paeoniflorin to improve the symptoms of DR.

Oxidative stress due to hyperglycemia damages the functions of retinal pigment epithelial (RPE) cells and is a major risk factor for diabetic retinopathy (DR). Paeoniflorin is a monoterpenoid glycoside found in the roots of Paeonia lactiflora Pall and has been reported to have a variety of health benefits. However, the mechanisms underlying its therapeutic effects on high glucose (HG)-induced oxidative damage in RPE cells are not fully understood. In this study, we investigated the protective effect of paeoniflorin against HG-induced oxidative damage in cultured human RPE ARPE-19 cells, an in vitro model of hyperglycemia. Pretreatment with paeoniflorin markedly reduced HG-induced cytotoxicity and DNA damage. Paeoniflorin inhibited HG-induced apoptosis by suppressing activation of the caspase cascade, and this suppression was associated with the blockade of cytochrome c release to cytoplasm by maintaining mitochondrial membrane stability. In addition, paeoniflorin suppressed the HG-induced production of reactive oxygen species (ROS), increased the phosphorylation of nuclear factor erythroid 2-related factor 2 (Nrf2), a key redox regulator, and the expression of its downstream factor heme oxygenase-1 (HO-1). On the other hand, zinc protoporphyrin (ZnPP), an inhibitor of HO-1, abolished the protective effect of paeoniflorin against ROS production in HG-treated cells. Furthermore, ZnPP reversed the protective effects of paeoniflorin against HG-induced cellular damage and induced mitochondrial damage, DNA injury, and apoptosis in paeoniflorin-treated cells. These results suggest that paeoniflorin protects RPE cells from HG-mediated oxidative stress-induced cytotoxicity by activating Nrf2/HO-1 signaling and highlight the potential therapeutic use of paeoniflorin to improve the symptoms of DR.

Oxidative stress due to hyperglycemia damages the functions of retinal pigment epithelial (RPE) cells and is a major risk factor for diabetic retinopathy (DR). Paeoniflorin is a monoterpenoid glycoside found in the roots of Paeonia lactiflora Pall and has been reported to have a variety of health benefits. However, the mechanisms underlying its therapeutic effects on high glucose (HG)-induced oxidative damage in RPE cells are not fully understood. In this study, we investigated the protective effect of paeoniflorin against HG-induced oxidative damage in cultured human RPE ARPE-19 cells, an in vitro model of hyperglycemia. Pretreatment with paeoniflorin markedly reduced HG-induced cytotoxicity and DNA damage. Paeoniflorin inhibited HG-induced apoptosis by suppressing activation of the caspase cascade, and this suppression was associated with the blockade of cytochrome c release to cytoplasm by maintaining mitochondrial membrane stability. In addition, paeoniflorin suppressed the HG-induced production of reactive oxygen species (ROS), increased the phosphorylation of nuclear factor erythroid 2-related factor 2 (Nrf2), a key redox regulator, and the expression of its downstream factor heme oxygenase-1 (HO-1). On the other hand, zinc protoporphyrin (ZnPP), an inhibitor of HO-1, abolished the protective effect of paeoniflorin against ROS production in HG-treated cells. Furthermore, ZnPP reversed the protective effects of paeoniflorin against HG-induced cellular damage and induced mitochondrial damage, DNA injury, and apoptosis in paeoniflorin-treated cells. These results suggest that paeoniflorin protects RPE cells from HG-mediated oxidative stress-induced cytotoxicity by activating Nrf2/HO-1 signaling and highlight the potential therapeutic use of paeoniflorin to improve the symptoms of DR.

BACKGROUND/OBJECTIVES: Recently, herbal medicines have gained attention for the treatment of benign prostatic hyperplasia (BPH), a common disease in elderly men. In this study, we aimed to determine the effect of ethanol extract of Asparagi radix (EAR), which is traditionally used to treat various diseases, on BPH development using a testosteroneinduced BPH model.MATERIALS/METHODS: Testosterone propionate (TP)-treated Sprague–Dawley rats were used to establish a BPH model in vivo. EAR was orally administered along with TP, and finasteride was used as a positive control. All rats were sacrificed at the end of the experiment, and pathological changes in the prostate tissue and levels of key biomarkers associated with BPH pathogenesis were assessed. RESULTS: Oral administration of EAR significantly inhibited TP-induced BPH by reducing the prostate weight, lumen size, and epithelial thickness in a concentration-dependent manner. EAR also significantly abrogated the expression of 5α-reductase type 2 (SRD5A2), proliferating cell nuclear antigen, and prostate-specific antigen (PSA) induced by TP.Additionally, serum levels of testosterone, dihydrotestosterone, and PSA were elevated in the TP-induced group but decreased in the EAR-treated group. EAR also decreased the expression levels of the androgen receptor (AR) and its coactivators in TP-induced BPH model rats. CONCLUSION Our findings revealed that EAR protected against BPH by inhibiting 5α-reductase activity and AR signaling pathway, suggesting its potential for BPH treatment.

BACKGROUND/OBJECTIVES: Recently, herbal medicines have gained attention for the treatment of benign prostatic hyperplasia (BPH), a common disease in elderly men. In this study, we aimed to determine the effect of ethanol extract of Asparagi radix (EAR), which is traditionally used to treat various diseases, on BPH development using a testosteroneinduced BPH model.MATERIALS/METHODS: Testosterone propionate (TP)-treated Sprague–Dawley rats were used to establish a BPH model in vivo. EAR was orally administered along with TP, and finasteride was used as a positive control. All rats were sacrificed at the end of the experiment, and pathological changes in the prostate tissue and levels of key biomarkers associated with BPH pathogenesis were assessed. RESULTS: Oral administration of EAR significantly inhibited TP-induced BPH by reducing the prostate weight, lumen size, and epithelial thickness in a concentration-dependent manner. EAR also significantly abrogated the expression of 5α-reductase type 2 (SRD5A2), proliferating cell nuclear antigen, and prostate-specific antigen (PSA) induced by TP.Additionally, serum levels of testosterone, dihydrotestosterone, and PSA were elevated in the TP-induced group but decreased in the EAR-treated group. EAR also decreased the expression levels of the androgen receptor (AR) and its coactivators in TP-induced BPH model rats. CONCLUSION Our findings revealed that EAR protected against BPH by inhibiting 5α-reductase activity and AR signaling pathway, suggesting its potential for BPH treatment.