Bone mass recovery of osteopenic-vitamin D insufficient rats from strontium ranelate treatment:Does the response depend on vitamin D nutritional status or on source of vitamin D (D2 vs. D3)?

GONZALES CHAVES M; MAROTTE C; PELLEGRINI G; PIGHIN A; DE LANDETA MC; FIMA LIFSHITZ; FRIEDMAN S; MANDALUNIS P; ZENI SN

Journal of Musculoskeletal Research

JMER

Lugar: Atenas; Año: 2010 vol. 13 p. 95 - 108

0218-9577

It was investigated if vitamin D (vitD) status or source (D2 vs. D3) interferes with bone mass recovery from strontium ranelate (SrRa) treatment of rats with vitD insufficiency and established osteopenia. Osteopenic and vitD insufficient rats were divided in groups to complete a 105-day period. 1st experiment: they were fed diets that only varied in vitD (100 vs. 0 IU%) and/or SrRa (0 vs. 900mg/kg/day) content. A SHAM group received vit D throughout the experience. 2nd experiment: rats were divided to receive vitD2 or vitD3 by diet and SrRa by gavages in a fasting state. Two SHAM groups received vitD2 or vitD3 throughout the study. Results: Levels of 25OHD were reduced in groups lacking dietary vitD (p<0.001). Independently of vitD status or source, SrRa did not affect body weight gain or bone alkaline phosphatase levels; osteocalcin and C-terminal telopeptide of type I collagen levels were reduced (p<0.05) and bone Sr content was increased (p<0.0001), although no improvement in biomechanical parameters was observed; total skeleton bone mineral content and proximal tibial bone mineral density were increased (p<0.05); there was a reduction in the trabecular number and, an increase in the trabecular surface and bone volume without reaching SHAM levels. Conclusion: This is the first study which examined SrRa effects in an osteopenic vitamin D-insufficient experimental model. Under our experimental condition, SrRa increased bone Sr content independently of vitD status or source, however no evidence of an anabolic or anti-fracture effect was found and only a slight decrease in some bone resorption parameters were observed.