The Effect Of Curcumin On Bone Loss In Ovariectomized Rats

Object:Postmenopausal osteoporosis (PMOP) is the osteoporosis caused by theimbalance between bone resorption of osteoclasts and bone formation ofosteoblasts because of a deficiency of estrogen after the menopause,belonging to primary osteoporosis. The characteristics of the disease areeasy fractures and high morbidity and mortality, and it seriously affectsmiddle-aged and old women’s health and life. With the increase of agingpopulation, postmenopausal osteoporosis problem more and morehighlighted. In recent years, home and abroad studies have confirmed thatoxidative stress plays an important role in the pathogenesis of osteoporosisin postmenopausal women. It has become a new concept with naturalantioxidant to prevent and treat osteoporosis.Curcumin (C) is a natural antioxidant, and it can induce theexpression of heme oxygenase-1(HO-1) in many organizations to reduceoxidative stress, and thus plays a protective role in the organization. In thepresent study, we used overiectomized (OVX) rats to establish the model ofthe postmenopausal osteoporosis, gave curcuminadministered orally asintervention factor, and measured the content of the oxidative stressindicators malondialdehyde (MDA), and the vitality of antioxidant enzymesuperoxide dismutase (SOD) in serum using the thiobarbituric acid (TBA)method and Water-soluble tetrazolium (WST-1) method, and determinatedthe expression changes of HO-1in bone tissue, in order to investigate theeffect of curcumin on the bone loss of OVX rats and its mechanism, andprovide a theoretical basis for finding a safe and effective prevention andtreatment methods.Methods:1The grouping and duplication of model of postmenopausal osteoporosis50Clean level female Sprague/Dawley rats at the age of3month wererandomly divided into5groups (10in each group):①Sham-operated(Sham),②OVX,③OVX treated withEstradiol valerate (OVX+E),④OVXtreated with high dose curcumin(OVX+HC),⑤OVX treated with lower dosecurcumin(OVX+LC). The rats were injected with10%chloralhydrate(0.35ml/100g weight) through abdominal cavity before surgery. Underaseptic condition, from the middle longitudinal incision of the small of theback entered into the abdominal cavity, then removed bilateral ovaries ofrats in group②-⑤and an equivalent weight of adipose tissue below bilateralovaries of rats in group①.7days after surgery, different groups of rats wereadministrated intragastricly separately with different drugs for12weeks.Rats in OVX+E group were treated with estradiol valerate at0.833mg/kg.d,and rats in OVX+HC group were treated with curcumin at200mg/kg. day.Rats in OVX+LC group were treated with curcumin at100mg/kg.day, whilerats in the Sham group and OVX group were given an corresponding volumeof0.5%sodium carboxymethyl cellulose solutionan per day, according to10ml/Kg body weight. The dosages of drugs were proofread per week inaccordance with their body weights.2Dual-energy X-ray absorption method measure bone mineral density(BMD)12weeks after treatment, the rats were taken placed on the Osteocore3dual energy X-ray absorptiometry, the bone mineral density of the femur andlumbar were measured by computer systems center animals software.3Hematoxylin-eosin stain and immunohistochemistry stain, SerumSOD, MDA levels measurementThe rats were sacrificed after drawing2ml blood from the heart.Weobtained the femurs and performed hematoxylin-eosin stain andimmunohistochemistry stain. The HO-1levels in bone tissue weredetermined by immunohistochemistry techniques. The level of MDA andSOD in serum were determined by the method of TBA and WST-1 respectively.4Result and image analysisWe applied One-Way ANOVA using Statistical Product and ServiceSolutons16.0(SPSS16.0) for data analysis. All values were demonstrated byaverage±standard deviation(Ｘ－±S).And two-two comparison among themeans were done by Student-Neuman-Keuls. P＜0.05was consideredstatistically significant.Results:1The bone mineral densityCompared with the sham-operated group, the BMD of the femur andlumbar reduced in OVX group and OVX+LC group, and the differenceswere statistically significant (P＜0.05,P＜0.05). There were no significantdifferences in OVX+E group (P＞0.05). The BMD of the femur reduced inOVX+HC group, and the differences were statistically significant (P＜0.05),while the BMD of the lumbar had no significant differences in OVX+HCgroup(P＞0.05). Compared with OVX group, the BMD of the femur andlumbar increased in OVX+E group,OVX+HC and OVX+LC group(P＜0.05,P＜0.05,P＜0.05). Compared with OVX+E group, the BMD of thefemur and lumbar reduced in OVX+LC, and the differences werestatistically significant(P＜0.05), while there were no significant differencesin OVX+HC group(P＞0.05). Compared with OVX+LC group, the BMD ofthe femur and lumbar increased in OVX+HC group. The differences werestatistically significant(P＜0.05).2The observation of bone tissue morphology(1)Sham operation group: bone trabecula arranged vertically,interconnected reticulate, arranged densely and regularly. The number ofbone trabecula plentiful, and trabecular separation was narrow. The corticalbone was dense.(2)Ovariectomized group: bone trabecula fractured,arranged sparsely and irregularly. No reticulate structure was seen and alarge number of trabecular bone blind side was seen. The trabecular becamethinner, trabecular separation became wider, and the cortical bone became thinner compared with sham group.(3)The OVX+E group shared similarchanges with sham-operated group, in the trabecular number, trabecularthickness, trabecular separation, trabecular length, trabecular distributionand continuity were greatly improved in the OVX+HC and OVX+LC groupcompared with the OVX group, and the OVX+HC group improved moreobviously.3The observation result of the immunohistochemistry stainThe expression characteristic of HO-1in bone tissue: The HO-1positive signal is in the osteoblast around bone trabecula, chondrocyte andbone marrow. The expression of HO-1protein was only a small amount inthe Sham and OVX+E group, and there were no significant differencesbetween the two groups(P＞0.05). The expression of HO-1protein in OVXgroup was enhanced, compared with the two groups(P＜0.05), while itsexpression in OVX+HC group and OVX+LC group was higher than theother three groups (P＜0.05,P＜0.05). The expression of HO-1protein inOVX+HC group was higher than that in the OVX+LC group (P <0.05).4The level of SOD, MDA in serumCompared with the sham-operated group, the content of MDA inserum was increased, while the activity of SOD in serum was reduced inOVX group,OVX+HC group and OVX+HC group(P＜0.05,P＜0.05,P＜0.05). There was no significant differences in OVX+E group(P＞0.05).Compared with OVX group, the content of MDA in serum was reduced,while the activity of SOD in serum was increased in OVX+E group,OVX+HC group and OVX+LC group(P＜0.05,P＜0.05,P＜0.05).Compared with OVX+E group, the content of MDA in serum was increased,while the activity of SOD in serum was reduced in OVX+LC group. Thecontent of MDA in serum had no significant differences in OVX+HC group(P＞0.05), and the activity of SOD in serum was reduced in OVX+HCgroup (P <0.05). Compared with OVX+LC group, the content of MDA inserum was reduced, while the activity of SOD in serum was increased inOVX+HC group (P＜0.05). 5The correlation analysis resultThe activity of SOD in serum of each group rats were positivelycorrelated with the BMD of the left femur and lumbar(r=0.884P<0.01,r=0.890P<0.01),while the content of MDA in serum werenegatively correlated with the BMD of the left femur and lumbar（r=-0.889P<0.01, r=-0.881P<0.01).There was no correlation between the expression of HO-1with theBMD of the left femur in Sham group,OVX group and OVX+E group（r=0.292P＞0.05, r=0.592P＞0.05,r=0.577P＞0.05. The expressionlevels of HO-1were positively correlated with the BMD of the left femur inOVX+LC group and OVX+HC group (r=0.885P<0.05, r=0.861P<0.05).Conclusions:1Oxidative stress plays an important role in the OVX-associated bornloss.2Curcumin can enhance the BMD of OVX rats, and inhibit the boneloss following ovariectomy.3Curcumin can increase the activity of the antioxidant enzymes SODand reduce the content of the oxidation marks MDA in serum of the OVXrats, and improve the oxidative stress state of the OVX rats.4The mechanism of preventing bone loss by curcumin might bethrough inducing the expression of HO-1in bone tissue, then reducingoxidative stress in ovariectomized rats.