This study was to determine the bone protective effects and underlying mechanisms of Osthole (OT) in ovariectomized (OVX) mice. We found that the inhibitory effects of OT on receptor activator of nuclear factor kappa-B ligand (RANKL)-activated osteoclastogenesis are responsible for its bone protective effects in OVX mice.
Eight-week-old mice were ovariectomized and OT (10 mg/kg/d) was intraperitoneally administrated to OVX mice 7 days after the surgery and were sacrificed at the end of the 3 months. Osteoclasts were generated from primary bone marrow macrophages (BMMs) to investigate the inhibitory effects of OT. The activity of RANKL-activated signaling was simultaneously analyzed in vitro and in vivo using immunohistochemistry, Western blot, and PCR assays.
OT dose dependently inhibited RANKL-mediated osteoclastogenesis in BMM cultures. OT administration attenuated bone loss (mg Ha/cm: 894.68 ± 33.56 vs 748.08 ± 19.51, P
< 0.05) in OVX mice. OT inhibits osteoclastogenesis (Oc.N/per view area: 72 ± 4.3 vs 0.8 ± 0.4, P
< 0.05) and bone resorption activity (bone resorbed percentages %, 48.56 ± 7.25 vs 3.25 ± 1.37, P
< 0.05) from BMMs. Mechanistically, OT inhibited the expressions of nuclear factor of activated T-cells c1 (NFATc1) and c-Fos. Moreover, OT suppressed the expression of RANKL-induced osteoclast marker genes, including matrix metalloproteinase 9 (MMP9), Cathepsin K (Ctsk), tartrate-resistant acid phosphatase (TRAP), and carbonic anhydrase II (Car2).
OT inhibits RANKL-mediated osteoclastogenesis and prevents bone loss in OVX mice. Our findings revealed that OT is a potential new drug for treating postmenopausal osteoporosis.
1Longhua Hospital, Shanghai University of Traditional Chinese Medicine (TCM), Shanghai, China
2Spine Research Institute, Shanghai University of TCM, Shanghai, China
3Key Laboratory of Theory and Therapy of Muscles and Bones, Ministry of Education (Shanghai University of TCM), Shanghai, China
4School of Rehabilitation Science, Shanghai University of TCM, Shanghai, China
5Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, Shreveport, LA.
Address correspondence to: Bing Shu, PhD, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Room 809, Building 12, 725 South Wanping Road, Shanghai 200032, China. E-mail: email@example.com
Received 16 March, 2018
Revised 4 May, 2018
Accepted 4 May, 2018
DZ and QW equally contributed to this work.
Funding/support: This work was supported by the program for the National Natural Science foundation of China (81673991, 81603643, 81774329, 81528022, 81473701, and 81730107), Ministry of Science and Technology of China (Grant No. 2015RA4002), and Ministry of Education of China (IRT1270).
Financial disclosure/conflicts of interest: None reported.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.menopause.org).