RESUMO
Thetherapeuticeffectsofintermitentcyclicetidronatedisodium(HEBP)ofdifferentdosesonovariectomy-inducedosteoporosiswerestudied.53femaleWistarrats,weighingwithanaver-ageof266gmwererandomlydividedinto5groups.Gourp1hadbilateralovariectomy(OVX)andwasgivenlowdoseHEBPof25mg/kgBW/day;group2hadOVXandgivenmediumdoseHEBPof36mg/kgBW/day;group3hadOVXandgivenhighdoseHEBPof51mg/kgBW/day;group4hadOVXandgroup5hadshamOVX.HEBPwasadministratedoralyduringfastingfor5daysfolowedbyarestperiodof25daysandtheregimewasrepeatedfor3times.Alanimalsweresacrificedat90thdayafterOVX.RadioimmunoassayofserumestradiolconfirmedthesuccessofOVX.TheserumCaandPcon-tent,AKPaseactivity,femoralrelativedryweight,CaandPcontentwereanalysedrespectively.Therighttibiaewereprocessedundecalcifiedforquantitativebonehistomorphometry.TheresultsshowedthatthebonecalciumcontentandtrabecularbonevolumeofOVX-ratstreatedwithHEBP,especialywiththelowdosegroupwerehigherthanthatofthesimplyOVX-ratandtheboneturnoverparameterssuchasAKPaseactivity,boneformationsurface,boneresorptionsurface,activeformationsurface,bonemineralappositionrateandboneformationratewerelowerthanthoseofthesimplyOVX-rat.TheresultsindicatetheHEBPcouldretardthedegreeofosteopososisthroughreducingtheelevatedboneresorptionandboneturnoverinducedbyOVX.Meanwhile,theresultssuggestthattheefectoflowdoseHEBP(25mg/kgBW/day)wasmoreefectivethanthatofthehighdose.