The effects of rare earth ions on bone resorbing function of osteoclasts were studied by culturing Japanese white rabbit osteoclasts on bone slices. In order to evaluate the activity of osteoclasts, the number and sur...The effects of rare earth ions on bone resorbing function of osteoclasts were studied by culturing Japanese white rabbit osteoclasts on bone slices. In order to evaluate the activity of osteoclasts, the number and surface areas of lacunae were measured by photomicrography and image analysis, and the calcium concentration in the supernatant was measured by the atomic absorption spectrometry. The lacunae morphology was observed under a scanning electron microscope. The results indicated that La3+, Sm3+ and Er3+ at the concentration of 1.00?0-5, 1.00?0-6 and 1.00?10-7mol/L and Nd3+, Gd3+ and Dy3+ at the concentration of 1.00?10-5 and 1.00?0-6 mol/L inhibited osteoclastic activity as indicated by the dose-dependent reduction in the numbers and surface areas of the lacunae (P<0.01). On the contrary, the number and surface areas of lanunae were increased and osteoclastic bone resorbing function was significantly enhanced by La3+, Sm3+ and Er3+ at the concentration of 1.00?0-8 mol/L and Nd3+, Gd3+ and Dy3+ at the concentration of 1.00?0-7 mol/L (P<0.01). Nd3+, Gd3+ and Dy3+ had no effect on osteoclastic bone resorption function at concentrations as low as 1.00?0-8 mol/L (P>0.05). It is suggested that the effects of rare earth ions on osteoclastic bone resorption are bidirectional, depending on concentrations and species.展开更多
Intestinal absorption of two oxovanadium complexes, vanadyl acetylacetonate (VO(acac)2) and bis (maltolato)-oxovanadium (VO(ma)2), has been compared using Caco-2 monolayers as a model system. The two compounds are sim...Intestinal absorption of two oxovanadium complexes, vanadyl acetylacetonate (VO(acac)2) and bis (maltolato)-oxovanadium (VO(ma)2), has been compared using Caco-2 monolayers as a model system. The two compounds are similar in chemical structures but different in glucose-lowering effects. Our experimental results show that they are both transported via passive diffusion with apparent permeabilty coefficients (apical→basolateral) of (82.0 ± 6.7)× 10-7 and (14.6 ± 0.7)× 10-7 cm· s-1, respec-tively. This suggests that absorptivity of VO(acac)2 is much higher than that of VO(ma)2. This difference may be related to the metabolism of either compound, or its ligand, or both in the course of the transport. However, This difference in absorption will cause the great difference in bioavailability,which might account for better efficacy of VO(acac)2 than VO(ma)2 as the insulin-mimic agent.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.20031010).
文摘The effects of rare earth ions on bone resorbing function of osteoclasts were studied by culturing Japanese white rabbit osteoclasts on bone slices. In order to evaluate the activity of osteoclasts, the number and surface areas of lacunae were measured by photomicrography and image analysis, and the calcium concentration in the supernatant was measured by the atomic absorption spectrometry. The lacunae morphology was observed under a scanning electron microscope. The results indicated that La3+, Sm3+ and Er3+ at the concentration of 1.00?0-5, 1.00?0-6 and 1.00?10-7mol/L and Nd3+, Gd3+ and Dy3+ at the concentration of 1.00?10-5 and 1.00?0-6 mol/L inhibited osteoclastic activity as indicated by the dose-dependent reduction in the numbers and surface areas of the lacunae (P<0.01). On the contrary, the number and surface areas of lanunae were increased and osteoclastic bone resorbing function was significantly enhanced by La3+, Sm3+ and Er3+ at the concentration of 1.00?0-8 mol/L and Nd3+, Gd3+ and Dy3+ at the concentration of 1.00?0-7 mol/L (P<0.01). Nd3+, Gd3+ and Dy3+ had no effect on osteoclastic bone resorption function at concentrations as low as 1.00?0-8 mol/L (P>0.05). It is suggested that the effects of rare earth ions on osteoclastic bone resorption are bidirectional, depending on concentrations and species.
基金supported by the National Natural Science Foundation of China(Grant No.20101001)
文摘Intestinal absorption of two oxovanadium complexes, vanadyl acetylacetonate (VO(acac)2) and bis (maltolato)-oxovanadium (VO(ma)2), has been compared using Caco-2 monolayers as a model system. The two compounds are similar in chemical structures but different in glucose-lowering effects. Our experimental results show that they are both transported via passive diffusion with apparent permeabilty coefficients (apical→basolateral) of (82.0 ± 6.7)× 10-7 and (14.6 ± 0.7)× 10-7 cm· s-1, respec-tively. This suggests that absorptivity of VO(acac)2 is much higher than that of VO(ma)2. This difference may be related to the metabolism of either compound, or its ligand, or both in the course of the transport. However, This difference in absorption will cause the great difference in bioavailability,which might account for better efficacy of VO(acac)2 than VO(ma)2 as the insulin-mimic agent.
