Effect of polygonimitin C on bone formation and resorption in human osteoblast-like MG63 cells

Hua-Li Shi,Xue-Qing Jin,Zhuo-Ling Fu,Xin-Wei Li,Hai-Lian Ji,Xiao-Feng Yang

doi:10.4314/tjpr.v16i7.18

Abstract

Purpose: To investigate the effect of polygonimitin C (PC) on bone formation and resorption in human osteoblast-like MG63 cells.Methods: MG63 cells were treated with PC at doses of 0, 20, 40 or 80 μg/mL for 48 h, with an untreated group as control. The effect of PC on alkaline phosphatase (ALP) activity in MG63 cells was investigated by p-nitrophenyl phosphate disodium hexahydrate assay. Western blot assay was used to evaluate the effect of PC on the expressions of osterix (OSX), bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (RUNX-2), osteocalcin (OC), fibronectin (FN), type I collagen (COL I), osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL) proteins in MG63 cells.Results: ALP relative activity in MG63 cells treated with PC at 20, 40 or 80 μg/mL (123.58, 137.74 or 159.62 %, respectively) was significantly (p < 0.05 or 0.01) higher than that in control group (99.37 %). Expressions of OSX, BMP-2, RUNX-2, OC, FN, COL I and OPG proteins in MG63 cells treated with PC at 20, 40 or 80 μg/mL were significantly (p < 0.01) higher than those in control group. However, there were no statistically significant differences in RANKL protein expression between PC-treated MG63 cells and control group.Conclusion: These results show that PC exerts protective effects against osteoporosis by promoting bone formation and inhibiting bone resorption. Thus, PC may be useful in the development of new antiosteoporosis drugs.Keywords: Polygonimitin C, MG63 cells, Bone formation, Bone resorption, Osteoporosis

Highlights

Osteoporosis (OP) is characterized by weak bone, which manifests clinically in bone fractures [1]
MG63 cells were harvested after treatment with polygonimitin C (PC), and their total proteins were extracted with the aid of cell lysis buffer, ultrasound and centrifugation
After blocking with 5 % non-fat milk, the polyviylidene difluoride (PVDF) membranes were incubated with primary antibodies for β-actin, OSX, bone morphogenetic protein-2 (BMP-2), RUNX-2, OC, FN, COL I, OPG and RANKL overnight at 4oC

Summary

Introduction

Osteoporosis (OP) is characterized by weak bone, which manifests clinically in bone fractures [1]. It is a major public health problem which affects numerous people worldwide, and imposes significant mental stress and economic burden on family and society [2]. The etiology of OP may be primary, secondary or idiopathic [3]. Typical primary OP is sub-divided into postmenopausal and senile OP, while secondary OP is sub-divided into endocrine, metabolic, drug-induced and deficiency OP [3, 4]. In OP patients, the bone-forming function of osteoblasts is lower than the bone-resorbing function of osteoclasts [7]. The fundamental principle involved in the treatment of OP is to regulate the imbalance between the bone-forming function of osteoblasts and boneresorbing function of osteoclasts

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