Curcumin regulates EZH2/Wnt/ß-Catenin pathway in the mandible and femur of ovariectomized osteoporosis rats.

Osteoporosis (OP) behaves in different manners in different parts of the skeleton. This study aims to investigate the effects of curcumin on bone mass of the mandibular and femur from ovariectomized OP rats and to validate whether enhancer of zeste homolog 2 (EZH2)/Wnt/ß-Catenin pathway is involved in this process. Curcumin was administered intragastrically into ovariectomized rats for 12 weeks. The bone parameters and the morphology of the trabecular bone of the left mandible and left femur were assessed by micro-computed tomography assay. Morphological changes of the left mandible and left femur were evaluated by hematoxylin and eosin staining. The mRNA levels of EZH2, ß-Catenin, and Runx2 in the right mandible and right femur were examined by quantitative real-time polymerase chain reaction. Immunohistochemistry was performed to assess EZH2 expression. Both the mandible and femur exhibited OP-like changes in ovariectomized rats, while the mandible bone resorption was less than the femur bone resorption. Curcumin intragastric administration improved bone microstructure and promoted bone formation in the mandible and femur. Curcumin inhibited EZH2 mRNA level and induced that of ß-Catenin and Runx2 in the mandible and femur. Collectively, curcumin exerts protective effects against OP, possibly by regulating the EZH2/Wnt/ß-Catenin pathway.

[Effects of curcumin on EZH2 mRNA expression in the mandible and femur of ovariectomized osteoporosis rats].

PURPOSE: To study the effects of curcumin on EZH2 mRNA expression in the mandible and femur of ovariectomized osteoporosis rats,and to investigate its protective effect and mechanism. METHODS: Thirty female 6-month old SD rats were randomly divided into sham group,OVX group and experimental group. The rats in the experimental groups were given curcumin (110 mg/kg) by intragastric administration after ovariectomy, while rats in the sham group and OVX group were given the same dosage of carboxymethylcellulose sodium solution, once a day for 12 weeks. All rats were sacrificed after the last intragastric administration. The serum samples were collected for detemination of biochemistrical parameters. Micro-CT was used for bone parameters and the morphology of the trabecular bone of the left mandibles and femurs. The expression level of EZH2mRNA in right mandible and femurs tissue was detected by reverse transcription polymerase chain reaction (RT-PCR). SPSS22.0 software package was used for statistical analysis. RESULTS: The expression of EZH2mRNA in the OVX group was significantly higher than the sham group (P<0.05). Compared with the OVX group,curcumin increased BMD and improved bone microstructure, decreased serum contents of alkaline phosphatase,and down-regulated the expression levels of EZH2mRNA in bone tissues of rats with osteoporosis (P<0.05). CONCLUSIONS: Curcumin can effectively prevent the lose of bone volume of ovariectomized rats, and repaire bone microstructure. Its mechanism is related with down -regulation of EZH2mRNA.