| ObjectiveTo study the effect of Morinda officinalis oligosaccharide(MO)on femoral bone mineral density and bone microstructure,serum level of bone turnover index and the activation of OPG/RANKL signal axis in ovariectomized osteoporosis rats,and to explore the preventive and therapeutic effect of MO on postmenopausal osteoporosis(PMOP),so as to provide the theoretical basis for the clinical application of MO in the treatment of osteoporosis.MethodsThirty 3-month-old female SD rats were randomly divided into 4 groups according to body weight: Sham operative group(n = 6),Ovariectomized group(n = 10),Positive Control group(Positive group)(n = 6),Morinda officinalis oligosaccharide group(MO group)(n = 8).After one week of adaptive feeding,bilateral ovariectomy was operated in OVX group,positive group,MO group through dorsal approach to establish the pathological model of PMOP,Sham group only removed the same amount of adipose tissue around the ovaries through the same approach.The rats in MO group were given Morinda officinalis oligosaccharide 25mg/kg·d,while Positive control group were treated with alendronate 0.5mg/kg·d.The Sham group and OVX group were treated with double distilled water 0.1ml/kg·d,and the weight was measured and recorded every 3 days.The dosage of the drug was adjusted according to the weight of the rats.The rats in each group were given the drug continuously for 8 weeks.After treatment,rats were anesthetized with10% chloral hydrate.After laparotomy,blood was taken from abdominal aorta and bilateral femurs were taken.Bone mineral density and bone microstructure of distal femur were measured by Micro-CT.Serum level of the bone turnover index including BGP,P1 NP,TRACP-5b,CTX-1 were detected by Enzyme Linked Immunosorbent Assay(ELISA).Reverse transcription polymerase chain reaction(RT-q PCR)and Western blot(WB)was used to detect the m RNA and protein expression of OPG and RANKL in the femoral head of SD rats respectively.Results1.BMD and bone microstructure parameters: Compared with Sham group,Bone mineral density(BMD),Relative femoral bone volume(BV/TV),Trabecular bone numbers(Tb.N)of OVX group were significantly decreased(P<0.01),and Trabecular separation(Tb.Sp)and Structure model index(SMI)of OVX group was significantly increased(P<0.01).Compared with OVX group,BMD,BV/TV and Tb.N of Control group and Mo group were significantly increased(P<0.01),Tb.Sp and SMI decreased significantly(P<0.01).However,the trabecular thickness(Tb.Th)of femur between groups were no significant difference(P>0.05).2.ELISA serum test: Compared with Sham group,the serum level of BGP and P1 NP decreased significantly(P<0.01),while the serum level of TRACP-5b and CTX-1 of OVX group increased significantly(P<0.05),and the serum level BGP was found no significant difference.Compared with OVX group,the serum level of BGP of MO group increased significantly(P < 0.05),the serum level of P1 NP of MO group and Control group increased significantly(P < 0.01),while the serum level of TRACP-5b and CTX-1 of Control group and MO group decreased significantly(P<0.01).3.mRNA and protein expression of OPG and RANKL in bone tissue: RT-q PCR showed that compared with OVX group,the m RNA expression of OPG in Mo group increased significantly(P<0.01),and the m RNA expression of RANKL decreased significantly(P<0.01),OPG/RANKL ratio increased significantly and tended to Sham group(P<0.01).Compared with OVX group,the expression of OPG in MO group was significantly increased,while the expression of RANKL was significantly decreased.Conclusions1.Morinda officinalis oligosaccharides can promote the bone formation of ovariectomized osteoporosis rats,through increasing bone mass,optimizing trabecular morphology,and improving bone microstructure.2.Morinda officinalis oligosaccharides could improve bone metabolism,promote bone formation,inhibit bone resorption and reduce bone loss.3.Morinda officinalis oligosaccharides could increase OPG expression,inhibit RANKL expression,increase OPG/RANKL ratio,thus providing antiosteoporosis effect. |
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