BACKGROUND: After loss of teeth, the dynamic equilibrium between osteoblast and osteoclast in alveolar bone is destroyed because of systematic and local factors, and residual ridge resorption and atrophy occur irreversibly, which result in the loss of massive alveolar bone. Bone morphogenetic protein-7 (BMP-7) exerts an important effect in the development and traumatic repair of bone and tooth.OBJECTIVE: To investigate the effect of human recombinant bone morphogenetic protein-7 (rhBMP-7) on new bone formation of alveolar ridge and absorption of alveolar ridge.DESIGN: Control experiment.SETTING: Department of Orthodontics, Jinan Stomatological Hospital;Shangdong Academy of Medical Sciences.MATERIALS: This study was conducted at the Shangdong Academy of Medical Sciences from June 2003 to December 2004. Totally 28 New Zealand white rabbits, of either gender, weighing 2 kg, were used in this study.METHODS: Animal extracted wound models were created on the rabbits.The mandibular left and right central incisor of the rabbits were removed.Two carriers containing BMP7 complex (40 μg/each) were implanted into the mandibular right central incisor (experimental group), two empty carriers containing only phosphate buffer solution(PBS) (40 μg/each) were implanted into the mandibular left central incisor (control group). The animals were sacrificed at postoperative 2, 4, 8 and 12 weeks. The specimen from the operated regions were harvested and observed by scanning electron microscope, and calcium content and alkaline phosphatase (ALP) activity were also measured.MAIN OUTCOME MEASURES: ① Result of scanning electron microscope (SEM). ② ALP activity and calcium content.RESULTS: ① The bone wound healing was 4-6 weeks earlier in the experimental group than in the control group . ② The ALP activity was significantly higher in the experimental group than in the control group [week 2:(38.191±5.384, (19.821±2.084) μkat/g;week 4: (160.815±9.669), (126.709±1.634) μkat/g;week 8: (378.892±13.086),(225.212±1.884) μkat/g,P ＜ 0.01]. ③ The calcium was significantly higher in the experimental group than in the control group [week 2:(5.592±0.110), (0.913±0.064) mg/g;week 4: (8.654±0.177), ( 1.702±0.071 ) mg/g;week 8: (25.326±0.287), (5.980±0.145) mg/g,P ＜ 0.01]CONCLUSION: BMP-7, which is expressed in the prokaryocyte, possesses good role in augmenting alveolar ridge and promoting the healing of alveolar wound.

In this paper we studied cryopreservation of Cyclamen persicum Mill. callus to avoid variations produced by sub-culture. The callus in the logarithmic phase after sub-culture were used for experiments. Firstly, the callus were pre-cultured in culture-medium containing 4%, 6% or 8% sucrose for different time periods, transferred to different cryoprotectants to directly cryopreserve or incubated for 2 hours at -20 degrees C, then submersed in liquid nitrogen, lastly thawed rapidly in a waterbath at 37 degrees C, and washed with liquid culture-medium containing the corresponding concentration of sucrose. Cell survival rate was computed after stained by Neutral Red, and SPSS 13.0 software was used for statistical analysis. The results showed that sucrose concentration, pre-culture time, cryoprotectants had various impacts on cell survival rate. We have developed a simple but effective protocol for the cryopreservation of callus of C. persicum. Of the different protocols tested, 4%sucrose, pre-culturing for 3 days, No. 9 cryoprotectant and freezing directly after 30 minutes at 0 degrees C results in the highest cell survival rate.
Cryopreservation ; Culture Techniques ; methods ; Cyclamen ; growth & development