Résumé
Objective: To study La accumulation and microstructure change of leg bones of rats fed with La(NO 3) 3 in low dosage for a long term. Methods: After the rats were fed by La(NO 3) 3 in dosage of 2 mg?kg -1 ?d -1 for 6 months, the contents of La and Ca,P in the leg bones were determined by ICP MS and spectrophotometry; the microstructure changes of the leg bones were investigated by electron microscopy and X ray powder diffraction. Results: In the leg bones of tested rats, the contents of La and P increased greatly, and those of Ca did not change obviously, so that Ca/P ratio values decreased in comparison with the control group. Conclusion: La was accumulatied in the rat leg bones and the change of bone microstructure induced after the rats were fed with La(NO 3) 3 in low dosage for a long term.
Résumé
AIM: To investigate the role of transferrin/transferrin receptor system in transferrin-bound Yb 2 (Yb 2Tf) uptake by U-87 MG cells and the effect of transferrin-bound and -free Yb 2 on proliferation of U-87 MG cells. METHODS: Cell culture and ICP-MS measurement of Yb 2. RESULTS: Yb 2Tf uptake by U-87 MG cells increased with the concentrations of Yb 2Tf, and reached saturation as the concentration in the incubation medium was raised to about 2 ?mol/L. Also, Yb 2 uptake by the cells increased with increase of the mole ratio (Yb 2: apoTf), reaching a maximum at 1.5 mole ratio. Yb 2Tf in 0.4 ?mol/L significantly inhibited proliferation of U-87 MG cells, however, 10 ?mol/L Yb 3+ had no significant effect on proliferation of the cells. CONCLUSION: The uptake of Yb 2 by U-87 MG cells might be mediated by transferrin/transferrin receptor system. Transferrin-bound but not transferrin-free Yb 2 could significantly inhibit proliferation of U-87 MG cells.