Cistanoside A mediates p38/MAPK pathway to inhibit osteoclast activity

Li Yueyao; Zhang Min; Yang Jiaju

doi:10.12307/2025.300

Abstract：BACKGROUND:Cistanoside A has the effects of anti-inflammation,antioxidation,antioxidation,reducing renal damage and anti-osteoporosis,but its effect on osteoclast differentiation,function and its underlying molecular mechanisms remain unclear. OBJECTIVE:To investigate the effect of Cistanoside A on osteoclast differentiation and bone resorption induced by receptor activator of nuclear factor kappa-B ligand(RANKL)in vitro and its mechanism. METHODS:Bone marrow macrophages were obtained from the femur and tibia of 4-6-week-old C57BL/6 mice.The cytotoxic effect of Cistanoside A(5,10,20,40,80,and 160 μmol/L)on bone marrow macrophage viability was examined using the cell counting kit-8 assay kit.Tartrate-resistant acid phosphatase staining was performed to observe the effect of different concentrations of Cistanoside A on osteoblast differentiation and its effective intervention concentration was determined.There was positive control group,Cistanoside A low,medium,and high dose groups(40,80,and 160 μmol/L).After cell attachment,50 ng/mL RANKL was added to induce osteoblast differentiation,and the corresponding dose of Cistanoside A was added to the Cistanoside A low,medium,and high dose groups,respectively.F-actin ring and 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride staining were performed to detect the effects of Cistanoside A on the formation of osteoclasts.Toluidine blue staining of bone abrasion slices was used to observe the effects of Cistanoside A on bone resorption function of osteoclasts.The expression of upstream and downstream proteins of the JNK/MAPK pathway was detected by Western blot.The expression of genes related to osteoclast differentiation and bone resorption function such as tartrate-resistant acid phosphatase,DC-STAMP,Nfatc-1,Ctsk and c-Fos was detected by RT-qPCR. RESULTS AND CONCLUSION:Tartrate-resistant acid phosphatase staining,F-actin ring staining and resorption pit assay showed that Cistanoside A significantly inhibited RANKL-induced osteoclast differentiation and bone resorption in a dose-dependent manner compared with the positive control group.The results of RT-qPCR showed that compared with the positive control group,both high and low dose groups of Cistanoside A could significantly downregulate the mRNA expression of tartrate-resistant acid phosphatase,DC-STAMP,Nfatc-1,Ctsk and c-Fos in a dose-dependent manner.The results of western blot assay showed that the high dose group of Cistanoside A significantly inhibited the expression of p-JNK protein at 10,20,30 and 60 minutes of intervention;compared with the positive control group,Cistanoside A significantly inhibited the expression of Nfatc1 and c-Fos proteins in a dose-dependent manner.To conclude,Cistanoside A could inhibit the formation and bone resorption of osteoclasts by reducing the level of p-JNK protein,inhibiting the activation of MAPK pathway and the expression of key genes in osteoclasts.