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Naringin improves bone properties in ovariectomized mice and exerts oestrogen‐like activities in rat osteoblast‐like (UMR‐106) cells
Author(s) -
Pang WaiYin,
Wang XinLun,
Mok SauKeng,
Lai WanPing,
Chow HungKay,
Leung PingChung,
Yao XinSheng,
Wong ManSau
Publication year - 2010
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.2010.00664.x
Subject(s) - naringin , ovariectomized rat , osteoblast , endocrinology , medicine , chemistry , in vivo , pharmacology , biology , in vitro , biochemistry , estrogen , microbiology and biotechnology , chromatography
Background and purpose: Naringin, a flavanone glycoside in citrus fruits, has been recently reported to stimulate bone formation in vitro and in vivo . The present study was designed to determine if naringin could exert oestrogen‐like protective actions in bone. Experimental approach: Young C57/BL6J mice were ovariectomized (OVX) and treated orally with naringin (0.2 or 0.4 mg·g −1 ·day −1 ), 17β‐oestradiol (2 µg·g −1 ·day −1 ) or its vehicle for 6 weeks. Bone mineral densities (BMD) and polar stress‐strain index (SSI) were measured by peripheral quantitative computed tomography. Rat osteoblast‐like UMR‐106 cells were co‐incubated with the oestrogen receptor (ER) antagonist ICI 182780 to determine if the effects of naringin on osteoblastic functions were ER dependent. Functional transactivation of ERα and ERβ as well as ERα phosphorylation by naringin were also studied. Key results: Naringin at 0.4 mg·g −1 ·day −1 increased BMD at trabecular‐rich bone in OVX mice. Naringin (at both doses) significantly increased SSI at distal femur and lumbar spine and increased biomechanical strength (ultimate load and energy for breaking) at tibia diaphysis in OVX mice. The stimulatory effects of naringin on osteoblastic functions could be abolished by co‐incubation with ICI 182780 in UMR‐106 cells. Naringin failed to stimulate ERα‐ or ERβ‐mediated oestrogen response element‐dependent luciferase activity but could significantly induce ERα phosphorylation at serine 118, in UMR‐106 cells. Conclusions and implications: Naringin was effective in protecting against OVX‐induced bone loss in mice and its actions might be mediated through ligand‐independent activation of ER in osteoblastic cells.