Zoledronate reverses mandibular bone loss in osteoprotegerin-deficient mice
- 230 Downloads
To characterize the changes in osteoprotegerin-deficient (OPG−/−) mice mandibles and the possible mandibular bone loss prevention by zoledronate. This preventive effect in the mandible differed from that in the proximal tibia and was independent of the OPG pathway.
The study aimed to characterize both the changes in the mandible in osteoprotegerin-deficient (OPG−/−) mice and possible mandibular bone loss prevention by zoledronate.
Twenty-eight 6-week-old female mice (C57BL/6J), including OPG−/− (n = 21) and wild-type (WT) (n = 7) mice, were assigned to four groups after 2 weeks of acclimatization to local vivarium conditions: wild mice with vehicle (WT group); OPG−/− mice with vehicle (OPG−/− group); and OPG−/− mice that were subcutaneously injected with either 50 or 150 μg/kg zoledronate (Zol-50 and Zol-150 groups, respectively). Mice were sacrificed at 4 weeks after these treatments and after fasting for 12 h. Sera were harvested for biochemical analyses. The right mandible and tibia of each mouse were selected for microCT analysis. Student’s t-test was performed for comparisons of bone parameters at different sites in the WT group. Analysis of variance (ANOVA) was used to compare the biomarkers and bone parameters in the different treatment groups.
Serum bone-specific alkaline phosphatase (B-ALP) and tartrate-resistant acid phosphatase 5b (TRACP-5b) were significantly decreased in WT mice as compared to the levels in the OPG−/− mice (P < 0.05). Zoledronate treatment decreased the high serum B-ALP activity observed in OPG−/− mice to the levels seen in WT mice, while serum TRACP-5b concentrations were decreased to levels even lower than those in WT mice. There were substantial variations in BMD and microstructure of the mandibular and proximal tibial trabeculae. Mandibular bone loss was less affected by OPG gene deprivation than the proximal tibia was. Both zoledronate groups showed greater BMD, trabecular BV/TV, Tb.Th, Tb.N, and Conn.D and a significant decrease in Tb.Sp and SMI as compared to the findings in OPG−/− mice (P < 0.05). However, higher apparent BMD and more compact plate-like trabeculae were observed in the mandible after treatment with zoledronate as compared to the findings in the proximal tibia. No significant differences were found in any parameter in both zoledronate groups.
The present study showed that zoledronate could reverse the significant bone loss in mice mandibles that was induced by OPG gene deficiency. This preventive effect, which was accompanied with considerable inhibition of bone turnover, differed in the mandible and in the proximal tibia and was independent of the OPG pathway.
KeywordsBisphosphonate BMD Mandible MicroCT Microstructure Osteoprotegerin-deficient mice
- 10.Simonet WS, Lacey DL, Danstan CR, Kelley M, Chang MS, Lüthy R, Nguyen HQ, Wooden S, Bennett L, Boone T, Shimamoto G, DeRose M, Elliott R, Colombero A, Tan HL, Trail G, Sullivan J, Davy E, Bucay N, Renshaw-Gegg L, Hughes TM, Hill D, Pattison W, Campbell P, Sander S, Van G, Tarpley J, Derby P, Lee R, Boyle WJ (1997) Osteoprotegerin: A novel secreted protein involved in the regulation of bone density. Cell 89:309–319PubMedCrossRefGoogle Scholar
- 11.Kong YY, Yoshida H, Sarosi L, Tan HL, Timms E, Capparelli C, Morony S, Oliveira-dos-Santos AJ, Van G, Itie A, Khoo W, Wakeham A, Dunstan CR, Lacey DL, Mak TW, Boyle WJ, Penninger JM (1999) OPGL is a key regulation of osteoclastogenesis, lymphocyte development and lymphnode organogensis. Nature 397:315–323PubMedCrossRefGoogle Scholar
- 15.Mizuno A, Amizuka N, Irie K, Murakami A, Fujise N, Kanno T, Sato Y, Nakagawa N, Yasuda H, Mochizuki S, Gomibuchi T, Yano K, Shima N, Washida N, Tsuda E, Morinaga T, Higashio K, Ozawa H (1998) Severe osteoporosis in mice lacking osteoclastogenesis inhibitory factor/osteoprotegerin. Biochem Biophys Res Commun 29(247):610–615CrossRefGoogle Scholar
- 25.Mizuno A, Amizuka N, Irie K, Murakami A, Fujise N, Kanno T, Sato Y, Nakagawa N, Yasuda H, Mochizuki S, Gomibuchi T, Yano K, Shima N, Washida N, Tsuda E, Morinaga T, Higashio K, Ozawa H (1998) Severe osteoporosis in mice lacking osteoclastogenesis inhibitory factor/osteoprotegerin. Biochem Biophys Res Commun 247:610–615PubMedCrossRefGoogle Scholar
- 31.Yong Hee K, Gwan-shik K, Jeong-Hwa B (2002) Inhibitory action of bisphosphonates on bone resorption does not involve the regulation of RANKL and OPG expression. Exp Mol Med 34:145–151Google Scholar
- 40.Bamias A, Kastritis E, Bamia C, Moulopoulos LA, Melakopoulos I, Bozas G, Koutsoukou V, Gika D, Anagnostopoulos A, Papadimitriou C, Terpos E, Dimopoulos MA (2005) Osteonecrosis of the jaw in cancer after treatment with bisphosphonates: incidence and risk factors. J Clin Oncol 23:8580–8587PubMedCrossRefGoogle Scholar