The severe osteopenia induce by ovariectomy and a low protein intake was reduced by olpadronate treatment

MAROTTE C; GONZALES CHAVES M; PELLEGRINI GG; MANDALUNIS P; FRIEDMAN SM; ZENI SN

Viena, Austria

Congreso; ECTS; 2009

Previously we found that a low dietary protein intake in OVX rats induce a severe osteopenia. In the present study we investigated the effect of anticatabolic treatment with the aminobisphosphonate, olpadronate (OPD) in rats feeding a low protein, normal calcium diet. A total of 30 Wistar adult rats (300±50 g) were studied, 20 rats were ovariectomized (OVX) and 10 were SHAM operated. During 15 days post-surgery all rats were fed a commercial diet (Granave SA, Bs.As.) which supplied protein 15%, vitamin D 200UI% and 0.6% calcium. After that rats were divided in 4 groups and for an additional 60 days they received: G1: OVX +  2.5% casein diet. G2: OVX + 2.5% casein diet + 8ug OPD/100g rats one a week (intraperitoneally) . G3: SHAM + comercial diet (protein 15%) At baseline (Tb) and at the end of the experience (Tf) total skeleton bone mineral content (BMC: mg) and density (BMD: mg/cm2)) were measured by DXA (Small animal Software, Lunar DPX). Proximal tibia BMD (BMDpt) was evaluated using a specific ROI and changes in BMC and BMDpt between Tf and Tb was calculated.  Serum calcium (Ca: mg/dl), phosphorus, bone alkaline fosfatase (bAL) and osteocalcin (BGP) were also evaluated. At Tf bone volume of tibia (BV/TV %) was measured by histology. Results (mean± standard error):   G1 G2 G3 bAL Tf (UI/L) 74±11a 50±5b 45±4b Calcium (mg%) Tf 9.6±0.1a 8.7±0.1b 10.3±0.1c BGP (ng/ml) Tf 131.0±15.1a 111.2±12.7b 178±55c [BMCetf  - BMCet baseline ] (mg)   253±19a   1512±343b   2706±556c [tibia BMD f - tibia BMD baseline] (%)   0.0±0.4a   22.0±2.1b   59.2±5.2c BV/TV (%). 2.9±0.2a 7.1±0.9b 25.1±3.2c Different letters indicates a: p<0.05 The OVX and low protein intake reduced serum Ca and BGP as well as BV/TV and increase serum bAL and BMC and BMDpt compared to SHAM group. OPD treatment reduced serum bAL, Ca an BGP and increased BMC, BMDpt and BV/ compared to untreated group. However, G2 did not reach the bone mass parameter observed in SHAM group. Conclusions: The severe osteopenia induce by OVX and a low protein intake was reduced by OPD treatment. Grant PIP6843.CONICET