| Osteoporosis(OP) is a metabolic bone disease with the characteristic of decline in bone mass and destruction on bone microstructure. Bone fractures as the serious complications of OP, there was 1 case of osteoporotic fracture would happened in every 3 seconds in the global. Hip fracture, as the most serious type of osteoporotic fracture, patients forced to bed, the complicatio ns of bed sores, pneumonia, deep vein thrombosis, as well as risk of urinary tract infection and other serious complications were significantly increased. The risk of death increased 40 percent within one year after hip fracture, and increased 20 percent within five years, which seriously threatened the lives and health of patients, and placing heavy economic burdens on their family. Traditional systemic therapy to prevent osteoporotic hip fractures had more side effects and with poor compliance. In this experiment, a local sustained-release cure system was used to enhance hip bone strength in order to achieve the purpose of prevented osteoporotic hip fractures, meanwhile, to explore for the future clinical applications.Objective To research the effect of Zoledronic and Recombinant Human Bone Morphogenetic Protein-2(rh BMP-2) local injection on the bone strength of rabbit osteoporosis model. Method 30 female New Zealand white rabbits at the age of 5 months were used in this study, and 24 of which were randomly selected to give ovariectomy, the rest as a sham group. The above 24 rabbits were randomly divided into four groups according to the diverse application of drugs(BMP group: rh BMP-2; ZOL group: ZOL; B+Z group: rh BMP-2+ ZOL; NON group: normal saline) as soon as osteoporosis model successful. Serum was separated through the exsanguination from ear vein of the rabbits to use the appropriate Elisa Kit to detect the activities of alkaline phosphatase(ALP) and tartrate-resistant acid phosphatase(TRACP) on the day after the injection, 2 weeks, 4 weeks, 6 weeks, 8 weeks, 10 weeks, and 12 weeks after injection, respectively. The rabbits were killed at 6 weeks and 12 weeks, respectively. The femurs were respectively removed and tested for Micro-CT scans, and bone mechanical properties. Meanwhile, the growth rate of bone trabecula was measured by Tetracycline-Calcein Chemiluminescence technology. Results â‘ After 4 weeks, the activity of ALP in BMP group and B+Z group were apparently higher than ZOL group and NON group(P<0.05); From 6 weeks on, compared with the sham group, no significant difference of the activity of ALP in BMP group and B+Z group(P>0.05). â‘¡At 8 and 10 weeks, the activity of TRACP in B+Z group were obviously lower than sham group(P<0.05); Meanwhile, the decline of the activity of TRACP in ZOL group and B+Z group were earlier and faster than BMP group(P<0.05). â‘¢The growth rate of bone trabecula of BMP group was obviously higher than other groups at all the time(P<0.05); â—‹4 12-weeks after injection, the result of BMD, BV/TV, Tb.Th and Tb.N of B+Z group were all obviously higher than NON group(P<0.05), meanwhile, the result of Tb.Sp was lower than NON group(P<0.05); Besides, the bone mechanical properties: 6-weeks after injection,the shearing strength and shear modulus among showed no significant difference among BMP group, ZOL group and B+Z group(P>0.05), but higher than NON group(P<0.05); the shear strain of ZOL group was higher than NON group(P<0.05). The shearing strength,shear modulus and shear strain of B+Z group were all obviously higher than the other three test groups(P<0.05), and there was no significant difference compared with negative control group. Conclusion Application of rhbmp-2 combined with ZOL not only can better increase the bone mineral density, bone volume fraction(BV/TV), trabecular thickness(Tb.Th) and the trabecular number(Tb.N), but also reduce trabecular spacing at the injection site. Besides, the bone mechanical properties will significantly strengthen. |
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