ABSTRACT
<p><b>OBJECTIVE</b>To investigate the expression of receptor activator of nuclear factor-κB (RANK), its ligand RANKL, and osteoprotegerin, and observe the effects of αD3 on their expressions in male rats at different ages.</p><p><b>METHODS</b>Wistar rats at 6 weeks, 6 months, and 24 months (n=15) were examined for mRNA expressions of RANK/RANKL and osteoprotegerin in the left proximal femur using RT-PCR and for their protein expressions in the right femur using immunohistochemistry. RANK/RANKL and osteoprotegerin expressions were also detected in another 15 rats aged 24 months following intragastric administration of 0.05 µg/kg αD3 (3 times a week for 10 weeks).</p><p><b>RESULTS</b>Compared with 6-week-old rats, 6-month- and 24-month-old rats showed a 6.2-fold and 7.3-fold increase of RANKL mRNA expression, respectively (P<0.05), and osteoprotegerin mRNA levels increased slightly with age. αD3 treatment resulted in significantly increased expression of RANK in 24-month-old rats with a lowered RANKL/osteoprotegerin ratio. RANKL and osteoprotegerin were co-localized in the osteoblasts and chondrocytes. αD3 treatment also caused an increased expression of osteoprotegerin mRNA in 24-month-old rats.</p><p><b>CONCLUSION</b>The age-related increase of the ratio of RANKL/osteoprotegerin mRNA promotes osteoclast activity and bone turnover. αD3 has favorable effect on osteogenesis and suppress bone absorption in the femur possibly by reducing RANK expression and lowering RANKL/osteoprotegerin ratio.</p>
Subject(s)
Animals , Male , Rats , Age Factors , Chondrocytes , Metabolism , Femur , Metabolism , Osteoblasts , Metabolism , Osteoprotegerin , Genetics , Metabolism , RANK Ligand , Genetics , Metabolism , RNA, Messenger , Genetics , Rats, Wistar , Receptor Activator of Nuclear Factor-kappa B , Genetics , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of monofluorphosphate and alphaD3 on the bone mineral density of mandibular of ovariectomy rats.</p><p><b>METHODS</b>39 female Sprague-Dawley rats about 90 days of age were randomly divided into the following treatment groups and treated for 12 weeks: SHAM group, OVX group, MFP group, MFP+alphaD3 group. Rats of MFP group received monofluorphosphate by gastric feeding. Rats of MFP+alphaD3 group received monofluorphosphate and alphatD3 by gastric feeding. The femur and the mandibles were collected for histomorphometry and bone mineral density measurement.</p><p><b>RESULTS</b>The bone area, bone thick, and bone mineral density of femur in the OVX group were significantly lower than those of other groups, while the trabecular separation of the OVX group was significantly higher than that of other groups. The bone mineral density of mandible was increased in OVX group and MFP+alphaD3 group compared with SHAM group.</p><p><b>CONCLUSION</b>Monofluorphosphate and alphaD3 can obviously increase the mass of mandible. The bone mineral density of femur decreased after ovariectomy while it increased in mandibular.</p>