INVESTIGADORES
PELLEGRINI Gretel Gisela
congresos y reuniones científicas
Título:
Dietary strontium (Sr) in a model of established osteopenic rats reduce the levels of 25hidroxyvitamin D
Autor/es:
GONZALES CHAVES M; MAROTTE C; PELLEGRINI G; FRIEDMAN S; PIGHIN A; LANDETA MC; ZENI SN
Lugar:
Montreal, Canada
Reunión:
Congreso; 30 Annual Meetting ASBMR; 2008
Institución organizadora:
ASBMR
Resumen:
Previously we found that vitamin D (vitD) status (i.e.normal or insufficient) interferes with bone mass recovery from bisphosphonate therapy in a model of OVX rats with established osteopenia (Bone 39: 837,2006). Using this model we investigated bone recovery from SrRanelate (SrRa) therapy. After 15 days post surgery and during 45 days, 20 OVX rats fed a diet containing 200IU% D (+D) and 20 a diet lacking vitD (-D) to obtain osteopenic/vitD repleted or depleted groups. Thereafter, 10 –D and 10 +D OVX rats were treated with vehicle (-RaSr) or RaSr (900mg/kg/d) (+RaSr) for 45 days to obtain 4 subgroups (table). A SHAM group was run as control. At 0, 60 and 105 days total skeleton BMD and BMC(teBMC) were assessed by DXA, 25OHD by RIA (Diasorin) and serum Ca and phosphorus (P) by atomic absorption spectrophotometry (AAS) and colorimetric methods, respectively. At day 105, rats were sacrificed and tibia total bone volume (BV/TV) and Sr in bone were determined by histology and AAS, respectively. Results (mean±SE) Control +D+RaSr -D+RaSr    +D-RaSr -D-RaSr Sr in bone (ppm) 10.7±0.3a 488.5±32.0b 511.9±31.3b 12.5±0.3c 16.3±0.2c DTeBMC(mg)(105-60)d -0.18±0.08a 1.07±0.11b 1.13±0.30b 0.08±0.16c -0.54±0.27d BV/TV (%) 27.1±2.9a 4.2±1.2b 4.4±1.3b 2.8±0.4c 2.5±0.3c 25OHD at day 105 17.9±0.9a 9.8±0.7b 6.3±0.9c 18.6±0.3a 6.4±0.1c Different letter indicates a p<0.05. The were no differences in teBMC, bony Sr and BV/TV between +SrRa treated –D or +D groups. BV/BT in +RaSr was 50% higher than in -SrRa groups but only represented a 10% of SHAM level. The 25OHD levels were significantly lower in +D+RaSr than in +D-RaSr rats. Conclusions: under our experimental conditions Sr may be incorporated into the formed bone independently of vitamin D status. We surprisingly found a diminution in serum 25OHD in +D+SrRa treated rats compared to +D-SrRa groups suggesting, as previously found in chicks (this effect on rats was not previously reported), an inhibition of vitD metabolism to its functional metabolite of nutritional status, 25OHD. (J Biol Chem 247: 5520, 1972). Grant PIP 6483, CONICET.