AIM: To investigate the osteoclastogenic effect of conditioned medium of human multiple myeloma RPMI 8226 cells on preosteoclast RAW264. 7 cells. METHODS; The protein expression of soluble receptor activator of NF - kB ligand ( sRANKL) was detected by Western blotting. The morphological changes of RAW264. 7 cells were observed after tartrate - resistant acid phosphatase (TRAP) staining. The mRNA expression of TRAP and cathepsin K was e -valuated by RT - PCR. RESULTS: The result of Western blotting showed that conditioned medium of RPMI 8226 cells contained sRANKL. RPMI 8226 cell conditioned medium induced RAW264. 7 cells to differentiate into TRAP - positive multinuclear osteoclasts. Human neutralized RANKL monoclonal antibody suppressed the differentiation of preosteoclasts in a dose - dependent manner , which was induced by 30% RPMI 8226 cell conditioned medium. RPMI 8226 cell conditioned medium increased the mRNA expression of TRAP and cathepsin K in RAW 264. 7 cells. CONCLUSION; The sRANKL in conditioned medium of human multiple myeloma RPMI 8226 cells has the bioactivity to induce preosteoclast RAW 264. 7 cells to differentiate into TRAP - positive multinuclear osteoclasts. Human neutralized RANKL monoclonal antibody sup -presses the differentiation of preosteoclasts induced by sRANKL in a dose - dependent manner.%目的:探讨人多发性骨髓瘤RPMI 8226细胞条件培养液对破骨前体细胞RAW264.7的影响.方法:Western blotting检测可溶性核因子κB 受体激活剂配体(soluble receptor activator of NF-κB ligand,sRANKL)的蛋白表达.抗酒石酸酸性磷酸酶(tartrate-resistant acid phosphatase,TRAP)染色观察RAW264.7细胞的分化成熟情况.RT-PCR法检测RAW264.7细胞TRAP和cathepsin K mRNA的表达.结果:Western blotting法证实RPMI 8226细胞条件培养液中含有sRANKL.TRAP染色发现RPMI 8226细胞条件培养液能诱导RAW264.7细胞分化为TRAP阳性的多核成熟破骨细胞.人抑制性RANKL单克隆抗体拮抗30%RPMI 8226细胞条件培养液中sRANKL的作用,且具有剂量依赖性.30% RPMI 8226细胞条件培养液能刺激RAW264.7细胞上调TRAP和cathepsin K mRNA表达.结论:人多发性骨髓瘤细胞RPMI 8226条件培养液中的sRANKL具有促RAW264.7破骨前体细胞分化成TRAP阳性的多核成熟破骨细胞的生物活性.人抑制性RANKL单克隆抗体阻断30%RPMI 8226细胞条件培养液中sRANKL的诱导分化作用,且具有浓度依赖性.
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