Protective Effect Of Daidzein On Glucocorticoid-induced Osteoporosis Rats

BackgroundGlucocorticoid-induced osteoporosis (GIOP) is a kind of bone disease whichinduced by endogenous or exogenous glucocorticoid and characterized by decrease inbone biomechanical strength, fracture, increase the risk for metabolic. Its incidence isin the third place of osteoporosis (OP), after postmenopausal osteoporosis and senileosteoporosis. And its incidence is in the first place in the secondary OP occupied.Daidzein (DAI) is a kind of soybean isoflavone, its main physiological role of estrogenaction. Many studies have confirmed that daidzein could promote bone metabolism,inhibit bone transformation, and has effect in the treatment of postmenopausalosteoporosis. In order to observe the effect of daidzein intervention on bone marrow density (BMD), bone microstructure, biochemical index and bone biomechanicalstrength of GIOP Sprague-Dawley (SD) rat model, to provide the experimental basisfor the clinical prevention and treatment of glucocorticoid-induced osteoporosis.1. Effect of Daidzein on bone mass and bone microstructurein GIOP ratsObjectiveTo observe the effect of daidzein on bone mineral density (BMD), bone mineralcontent (BMC) and bone microstructure of glucocorticoids osteoporosis rat model.MethodsA total of303-month-old female Sprague–Dawley (SD) rats were randomlydivided into Control group (Con), glucocorticoid group (GCT group) and daidzeingroup (DAI). GCT group and DAI group were given prednisone7.5mg/kg lavage eachday, Con group was given equal normal saline. In addition, DAI group were givendaidzein5mg/kg lavage each day. After12weeks, the rats were sacrificed and examinethe lumbar1section and left tibia by micro-CT. Analysis parameters include: bonemineral content (BMC); Bone mineral density (BMD); Bone trabecular thickness(Tb.Th); Bone trabecular number (Tb.N); Bone trabecular spacing (Tb.Sp); Bonevolume fraction (BV/TV).Results(1) BMD and BMC of GCT group compared with Con group were significantlylower (P <0.01), suggesting building GIOP model success. There were significantlydifferences in BMD (L4) between DAI group and GCT group (P <0.05).(2) Tb.Th,Tb.N and BV/TV of left tibia in GCT group compared with Con group were lower,Tb.Sp of left tibia in GCT group were significantly higher than Con group (P <0.01). In DAI group, Tb.Th, BV/TV were higher than those in GCT group (P <0.05), Tb.Spdecreased significantly (P <0.01).ConclusionGlucocorticoids can decrease the BMD and BMC of lumbar4section of SD rats,reduce the number of trabecular bone, decrease the thickness of the bone trabecular、bone mineral density and bone volume fraction, increase the bone trabecular spacing.Daidzein can prevent the Bone mass reduction of glucocorticoid-induced osteoporosis(GIOP) in the rats, and protect the bone microstructure of GIOP rats.2. Effect of Daidzein on biochemical markers of bonemetabolism in GIOP ratsObjectiveTo evaluate the effect of Daidzein on prednisolone resulted in the rat model ofosteoporosis related biochemical indicators.Methods363months aged female SD rats as the research object, randomly divided intoControl group (CON,12rats), Prednisolone group (GCT,12rats) and daidzeinintervention group (group DAI,12rats). GCT group and DAI group were givenintragastric administration of prednisolone7.5mg/kg/d; Con group was given normalsaline. In addition, the rats of group DAI were given daidzein administrated with5mg/kg. Serum was separated in sixth weeks and twelfth weeks in each group wererandomly6rats were killed, blood biochemical indexes. The indexes included: bloodcalcium, phosphorus, bone alkaline phosphatase (b-ALP),C-telopeptide of type I collagen (CTX). Results(1) after six weeks, GCT group and DAI group compared with CON group, serumcalcium, phosphorus index increased slightly, but no significant difference; b-ALPindex of GCT group and DAI group were slightly low than CON group, but nostatistical difference between the three groups; CTX index in GCT group comparedwith CON group and DAI group was decreased, there were significant differencesP<0.05, there was no difference between DAI group and CON group.(2) After twelveweek, compared to sixth weeks, three groups of serum calcium, phosphorus decreasedslightly, but no significant difference between the three groups, the serum calcium,phosphorus level is not statistically significant; GCT group compared with CON groupand DAI group, serum b-ALP was significantly decreased (P<0.05), no differenc esbetween CON group and DAI group (P>0.05); GCT group compared with CON groupand DAI group, the serum levels of CTX were obviously increased (P<0.05), there wasno difference between group CON and group DAI (P>0.05).Conclusionthe serum calcium, phosphorus index was not too big effect, but can make theb-ALP index decreased, the CTX index increased; b-ALP index decreased with theincrease of Daidzein on prednisolone caused and CTX index have a certainantagonism.3. Effect of Daidzein on the biomechanics of GIOP ratsObjectiveTo evaluate the effect of Daidzein on prednisolone resulted in the rat model ofosteoporosis biomechanical strength index.Methods 303months aged female SD rats as the research object, randomly divided intoControl group (group CON,10rats), hormone group (group GCT,10rats) andhormone molding and daidzein intervention group (group DAI,10rats). GCT groupand DAI group were given intragastric administration of prednisolone7.5mg/kg/d;CON group was given normal saline. The rats were killed after12weeks, we separatedthe left femur of the rats, and did the bone biomechanical test. Detection parametersuse maximum load (Fmax) and elastic load (Fp).ResultsAfter12months treatment, compared with the rats in group CON, femoral Fmaxand Fp values of rats in group GCT were low, P<0.05, there are significant difference s;femoral Fp of rats in DAI group was lower than that in the CON group, but nosignificant difference; rats femoral Fmax values in group DAI were higher than thevalues in group GCT, but P>0.05, the rats in group DAI femoral Fp values were higherthan the GCT group, the P<0.05, there were significant differences.ConclusionGC can affect the biomechanical properties of femur of rats and increase the riskof fracture. Although compared to CON group, the femoral biomechanical strength ofrats that daidzein intervention decreased slightly, but the elastic load index was notstatistically significant. And because daidzein intervention, elastic load of rats weresignificant higher than that in GCT group. The above result showed that Daidzein onGC induced femoral biomechanical strength rats decreased has a preventive effect.