高糖条件下唑来膦酸通过内质网应激途径调控破骨细胞分化及骨吸收的机制OA

Objective To investigate the regulatory effects of zoledronic acid(ZA)on osteoclast differentiation and function via the endoplasmic reticulum stress(ERS)pathway under high-glucose conditions,as well as its association with the pathogene-sis of medication-related osteonecrosis of the jaw(MRONJ).Methods RAW264.7 cells were induced to differentiate into osteo-clasts and divided into six groups:control group(CON),ZA group(ZA),high-glucose group(HG),high-glucose+ZA group(HG+ZA),high-glucose+ZA+4-phenylbutyric acid group(HG+ZA+4-PBA),and high-glucose+ZA+tunicamycin group(HG+ZA+TM).The proliferative activity of RAW264.7 cells was detected with the CCK-8 assay.The number of osteoclasts was detected with TRAP staining.The bone resorption lacuna area was detected with toluidine blue staining.The integrity of F-actin rings in osteoclasts was detected with cellular immunofluorescence.The effects on osteoclast differentiation were evaluated with the aforementioned methods,and the mRNA and protein expression levels of ERS markers(GRP78,PERK,eIF2α,ATF4,and CHOP)were detected by RT-qPCR and Western blot,respectively.Results ZA regulated osteoclast differentiation and bone resorption function under high-glucose conditions.Compared with the CON group,the HG group showed decreased numbers of TRAP staining positive cells,reduced bone resorption lacuna areas,and compromised integrity of F-actin rings,which were fur-ther exacerbated by ZA(P＜0.05 or＜0.01).ZA regulated osteoclast differentiation and bone resorption function under high-glucose conditions through the ERS pathway.Compared with the CON group,the mRNA and protein expression levels of ERS pathway markers were decreased in the HG group,which were further exacerbated after the addition of ZA(P＜0.05 or＜0.01).Following the treatment with the ERS inhibitor,the inhibitory effect of ZA on osteoclasts was further exacerbated,where-as the addition of the ERS activator partially reversed this effect.Conclusion Under high-glucose conditions,ZA enhanced its inhibitory effects on osteoclast differentiation and function by suppressing the PERK-eIF2α-ATF4-CHOP ERS signaling pathway,which may be one of the important mechanisms underlying the increased risk of MRONJ in diabetic osteoporosis patients after ZA treatment.