Effects of strontium ranelate on bone strength and bone turnover markers in glucocorticoid induced osteoporosis model in wistar-albino rats

SUMMARYEFFECTS OF STRONTIUM RANELATE ON BONE STRENGTH AND BONETURNOVER MARKERS IN GLUCOCORTICOID INDUCED OSTEOPOROSISMODEL IN WISTAR-ALBINO RATSDr. Nusret YılmazDepartment of Internal Medicine, School of Medicine, Dokuz Eylul University. IzmirAddress for correspondence: DEUTF Ic Hastaliklari AD Inciralti / Izmir 35340E-mail: nusret.yilmaz@deu.edu.trAim: Glucocorticoids are one of the major causes of osteoporosis. Most drugs employedin osteoporosis treatment were also tried and prescribed with this indication. Strontiumranelate (SR) is approved for postmenopausal osteoporosis treatment. There are ongoing trialsevaluating the effects of this drug on glucocorticoid induced osteoporosis. In this study, wedemonstrated the effects of SR on bone turn-over markers and bone strength in Wistar-Albino rats with experimentally glucocorticoid induced osteoporosis.Method: Six groups of female Wistar-Albino rats [control group rats sacrificed on firstday (B1) and sacrificed at the end of sixteen week (B2); rats with osteoporosis induced byeight weeks treatment of methylprednisolon (OP1); rats with osteoporosis induced by sixteenweeks treatment of methylprednisolon (OP2); rats treated with SR 900 mg/kg/day for eightweeks after eight weeks of methylprednisolon treatment (TG); rats treated with vehicle (1%carboxymetylcellulose) for sixteen weeks (CMC-G)] were included in the study. Vertebraland femoral bone mineral density (BMD) and serum osteocalcin and C-telopeptide ofcollagen cross links (CTx) levels were measured. Vertebral bone strength was assessed bycompression test and femoral bone strength was assessed by three point bending test.Maximum load and maximum stress was measured by these tests. Statistical analyze wasdone with SPSS for windows. Mann Whitney-U test was applied. P values less than 0.05 wasaccepted as statistically significant.Results: Rats treated with SR had 30.8% (p=0,053) relatively more vertebral maximumload and 14.2% (p= 0.209) relatively more vertebral maximum compression stress comparedto those not treated with SR. The treatment group also had 6.4% (p=0,314) relatively morefemoral maximum load and 7.3% (p=0.209) relatively more femoral maximum bendingstress. None of these discrepancies were statistically significant.Conclusion: In this glucocorticoid induced osteoporosis model, we demonstratedstatistically insignificant increment of femoral and vertebral bone power with SR treatment.Key words: Strontium ranelate, Bone strength, Glucocorticoid, Osteoporosis.