[Effects of calcitonin on osteoblast cell proliferation and OPG/RANKL expression: experiment with mouse osteoblasts].

OBJECTIVE: To investigate the effects of calcitonin on the proliferation of osteoblasts and the OPG/RANKL expression therein. METHODS: Osteoblasts were separated by enzyme digestion methods from the cranial bones of 30 newborn mice, cultured, and inoculated in 96-well plate. Calcitonin of the concentrations of 10, 40, and 80 IU/L was administrated into the culture medium for 24, 48, and 72 hours. The proliferation of osteoblasts was detected by MTT method. Flow cytometry was used to analyze the cell cycle. The mRNA expression of osteoprotegerin (OPG) and RANKL and protein expression of OPG were examined by RT-PCR and ELISA respectively. RESULTS: The proliferation rates of the osteoblasts exposed to the calcitonin of the concentrations of 40 and 80 IU/L for 24. 48, and 72 hours cell were all significantly higher than those of the blank control group (P < 0.05, P < 0.01). The index of osteoblasts at the G1 phase was significantly lower and the indexes of the osteoblasts at the S phase and G2-M phase were significantly increased after exposure to calcitonin (all P < 0.01). The OPG mRNA expression of the osteoblasts exposed to 80 IU/L calcitonin was significantly higher and the RANKL mRNA expression was significantly lower compared with the control group (P < 0.05). The OPG protein expression of the osteoblasts exposed to 80 LU/L calcitonin was significantly higher than that of the control group at different time points (P < 0.05, P < 0.01). CONCLUSION: Calcitonin increases the osteoblast proliferation and the OPG mRNA expression in the osteoblasts while RANKL mRNA expression in the osteoblasts is inhibited.

[Effects of carbon monoxide on polymorphonuclear leukocyte apoptosis stimulated by limb ischemia-reperfusion patient serum and the role of nuclear factor-kappaB].

OBJECTIVE: To explore the role of exogenous carbon monoxide (CO) in apoptosis of polymorphonuclear leukocyte (PMN) stimulated by ischemia-reperfusion (IR). METHODS: PMNs isolated from the venous blood of a healthy volunteer, incubated, put in 24-well plates, and randomly divided into 4 groups of 8 wells: control group (exposed to 5% CO2), control + CO group (exposed to 0.025% CO and 5% CO2 for I hour and then serum of healthy person was used to replace the culture fluid), IR group (exposed to 5% CO2 and then IR serum was used to replace the culture fluid), and IR + CO group (exposed to 0.025% CO and 5% CO2 for I hour and then serum of healthy person was used to replace the culture fluid). The IR serum was obtained from 8 male patients with osteoarthritis of knee undergoing knee replacement. After 24-hour incubation the PMNs underwent flow cytometry and electrophoresis to examine the apoptosis of PMNs. Electrophoretic mobility shift assay (EMSA) was used to detect the NF-kappaB binding activity. RESULTS: The PMN apoptotic rate of the IR + CO group was 9.38% +/- 1.58%, significantly higher than that of the control group (4.18% +/- 1.02%, P < 0.05). The PMN apoptotic rate of the IR group was 2.15% +/- 1.02%, significantly lower than that of the control group (P < 0.05). However, the PMN apoptotic rate of the control + CO group was 4.16% +/- 1.12%, not significantly different from that of the control group (P > 0.05). Electrophoresis showed that PMN apoptosis DNA ladder was seen in the control, control + CO, and IR + CO groups, but not in the IR group. EMSA showed that after co-incubation of PMN nuclear extract and isotope- labeled NF-kappaB probe in term of the strength of radiation self-development band the result the IR group was significantly greater than that of the control group, and the result of the IR + CO group was significantly lower than that of the IR group, however, there was no significant difference between the control and control + CO groups. CONCLUSION: Exogenous CO improves the inhibitory effect of IR blood on the PMN apoptosis with a mechanism of suppressing the NF-kappaB binding activity.

Comparison of Tension-Band Wiring With the Cable Pin System in Patella Fractures: A Randomized Prospective Study.

OBJECTIVES: To compare the outcome of tension-band wiring (TBW) with the cable pin system (CPS) for transverse fractures of the patella. DESIGN: Randomized prospective study. SETTING: Academic Level I trauma center. PATIENTS/PARTICIPANTS: From February 2008 to December 2011, 73 consecutive patients with transverse fractures of the patella were prospectively enrolled in this study. INTERVENTION: The patients were randomly divided into 2 groups: one group was treated using the CPS, and the other group was treated using the modified TBW. MAIN OUTCOME MEASUREMENTS: The clinical outcome assessment included analyses of the radiographic images, the modified Hospital for Special Surgery scoring system, and complications. RESULTS: The follow-up time ranged from 12 to 29 months. All fractures healed, with a union rate of 100%. The fracture healing time was significantly shorter in the CPS group (8.51 ± 2.59 weeks, n = 34) compared with the TBW group (11.79 ± 3.04 weeks, n = 39). Postoperative complications in the CPS and TBW groups were observed in 1 and 9 patients, respectively, a difference that was statistically significant. The mean Hospital for Special Surgery score for the CPS group (90.53 ± 5.19 points) was significantly higher than that for the TBW group (81.36 ± 12.71 points). CONCLUSIONS: The CPS is a viable option for transverse fractures of the patella and is associated with a shorter healing time, fewer complications, and better function than TBW. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

[Effects of 1,25-dihydroxyvitamin D3 on the expressions of osteoprotegerin and receptor activator of NF-kappaB ligand in mouse osteoblasts].

OBJECTIVE: To study the effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on the expression of osteoprotegerin (OPG) and receptor activator of NF-kappaB ligand (RANKL) mRNA in mouse osteoblasts. METHODS: Calvariae derived from CD-1 neonatal mouse (after born 24 h). Bone samples were processed by the collagenase/trypsin digestion method. Mouse osteoblasts were cultured in vitro. After 48 hours of addition of 1,25(OH)2D3 (0, 10(-8), 10(-9), 10(-11) mol/L) to the culture medium of mouse osteoblasts, the content of the OPG protein in culture medium was estimated with enzyme linked immunosorbent assay. Total RNA was prepared from mouse osteoblasts. mRNA expression of OPG and RANKL were detected by reverse transcription-polymerase chain reaction. RESULTS: The mRNA expression of OPG in osteoblasts added with 1,25(OH)2D3 significantly decreased compared with the controls, which was markedly dose-dependent. OPG protein production in the medium decreased after treatment with 1,25(OH)2D3. In contrast, RANKL mRNA expression levels in osteoblasts significantly increased after 48 h of culture with 1,25(OH)2D3. CONCLUSION: 1,25 (OH)2D3 can stimulate RANKL mRNA expression, but decrease OPG mRNA levels in vitro in mouse osteoblasts.