title: Zinc enhances bone metabolism in ovariectomized rats and exerts anabolic osteoblastic/adipocytic marrow effects ex vivo.
abstract: Investigations of bone mass and marrow adiposity are critical for defining the role of zinc (Zn) in bone metabolism. Rats used for study were grouped as follows: control (sham), ovariectomy (OVX), ovariectomy + estradiol (OVX-E), ovariectomy + Zn treatment (OVX-Zn). Bone mineral density (BMD) was quantified (microCT); serum osteocalcin, adiponectin, RANKL, and TRAP levels were assayed (ELISA); and biochemical determinations of serum alkaline phosphatase (ALP), calcium (Ca), and phosphorus (P) were done. Cells derived from bone mesenchymal stem cell (BMSC) isolates of respective test groups were compared, identifying primary osteoblasts by MTT assay and adipocytes by Oil Red O stain. Osteocalcin and adiponectin levels in culture supernatants were determined by ELISA. Zn supplementation resulted in a modest increase in BMD, but serum osteocalcin and ALP activity increased significantly (P < 0.01, both). Serum levels of RANKL and TRAP were lower in OVX-Zn (vs OVX) rats (P < 0.01), whereas serum concentrations of adiponectin, Ca, and P did not differ by group. Osteocalcin level was significantly upregulated ex vivo (P < 0.01) in the supernatant of cultured OVX-Zn (vs OVX) cells, accompanied by a slight upturn in osteoblastic differentiation. However, Oil Red O uptake and adiponectin level in supernatant were sharply diminished in cultured OVX-Zn (vs OVX) cells (P < 0.01). Overall, we concluded that Zn contributes to bone mass by marginally stimulating differentiation and proliferation of osteoblasts and by effectively inhibiting osteoclastic and adipocytic differentiation of BMSCs.
authors.affiliation: Department of Oral Pathology, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing, 100081, People's Republic of China, kqlibinbin@aliyun.com.
authors.forename: Binbin
authors.initials: B
authors.lastname: Li
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.forename: Shengnan
authors.initials: S
authors.lastname: Jia
mesh_terms: D000135:Acid Phosphatase / Q000097:blood; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D002478:Cells, Cultured; D005260:Female; D007527:Isoenzymes / Q000097:blood; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D015675:Osteocalcin / Q000097:blood; D010052:Ovariectomy; D010758:Phosphorus / Q000097:blood; D053245:RANK Ligand / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D000071681:Tartrate-Resistant Acid Phosphatase; D015032:Zinc / Q000494:pharmacology*
chemical_list: D007527:Isoenzymes; D053245:RANK Ligand; D015675:Osteocalcin; D010758:Phosphorus; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D015032:Zinc; D002118:Calcium