| Objective:1. To explore the effect of Naringin on osteoclast.2. To explore the effect of Naringin on osteoporosis in ovariectomized rats.3. To investigate the effects of naringin on bone healing of osteoporotic fracture. Method:1. In this study, RAW 264.7 cells were cultured with RANKL(100ng/ml), and naringin was applied for a given period. We counted the number of osteoclast cells which were tartrate-resistant acid phosphatase(TRAP)-positive and resorption pit assay, and measured osteoclast proliferation by flow cytometry. The m RNA expression levels of RANK, TRAP, MMP-9, NFATc1, and C-fos were detected by RT-PCR.2. Surgical removal both of ovaries in rats, After 60 days, the rats were randomly divided into sham operation group, estrogen group(22.5μg/kg), Naringin low, medium and high(40mg/kg, 100mg/kg, 200mg/kg) group. After treatment 60 days. The trabecular microstructure, histomorphometry analysis and mechanical of distal femur were detected in different groups.3. Sixty female Sprague-Dawley rats were oophorectomized before establishment of tibia fracture model. The fracture of right tibia was stabilized after 2 month. The rats were assigned to control group(n=20), naringin group(n=20) and estrogen group(n=20) according to random number table. Rats in naringin group received gavage of 100mg/kg naringin per day, estrogen group received 17-β-estradiol 22.5μg/kg per day. Instead, isotonic saline solution of the same volume was gavage given to rats in control group. Half of the animals in each group were killed at week 2 and 8 respectively. The tibias were dissected to perform X-ray Review, dual energy X-ray absorptiometry, Micro-CT, Serum analysis and Mechanical testing. Results:1. There was a decrease in the number of osteoclasts and bone resorption area under naringin compared with the control. And naringin significantly reduced osteoclast proliferation. Expression of m RNA for the osteoclast-specific genes, TRAP, MMP-9, NFATc1 and, decreased with mechanical stress and was associated with the number of osteoclasts.The expression of RANK m RNA showed no significant differences compared to control. In spite of the decrease in osteoclast number with naringin, C-fos m RNA expression increased with naringin.2. 60 days after treatment, Compared with Ovariectomized rats, the rats weight loss in medium and high dose of Naringin groups; increased bone mineral density and the number of trabecular bone in Naringin groups; serum calcium and aspartate aminotransferase(AST) decreased, increases of estrogen and calcium in Naringin groups.And Naringin proportional to the concentration; and CTX-1 and total cholesterol regulation.3. At week 2 following operation, X-ray score, BMD, Tb.Th, osteocalcin and maximum load were highered significantly in naringin group as compared to control group(P < 0.05); BV, BV/TV were higher in naringin group than in control group(P0.01); However, serum CTX-1 was lower than control group(P 0.05); BV, osteocalcin and maximum load were higher in naringin group as compared to control group(P 0.05). BMD, BV, BV/TV, Tb.Th, osteocalcin and maximum load in estrogen group also higher than control group(P 0.05). There were no signi?cant difference in X-ray score, BMD, BV / TV, Tb.Th, CTX-1 between naringin group and estrogen group. At week 8 following operation, naringin group presented higher X-ray score, BMD, BV, BV/TV, Tb.Th(P 0.05) as compared to control group(P < 0.05); However, there were no signi?cant difference between naringin group and estrogen group(P > 0.05). The osteocalcin and maximum load in naringin group signi?cant higher than control group and estrogen group(P < 0.05). Conclusion:These findings indicate that naringin promote osteoclasts apoptosis, increase the number of trabecular and bone mineral density in ovariectomized rats, regulation of body weight, blood biochemistry and bone metabolism, improve the mechanical properties of rat femur, promote fracture healing by improving the BMD, BV, BV/TV, Tb.Th, mechanical strength, and ameliorate bone metabolism. |
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