ABSTRACT
Objective:To explore one-stage total knee arthroplasty (TKA) combined with open reduction and internal fixation (ORIF) for knee osteoarthritis complicated with tibial stress fracture.Methods:The 3 patients were retrospectively analyzed who had been treated for knee osteoarthritis complicated with tibial stress fracture at Department of Orthopedics, Ganzhou District People＇s Hospital from March 2018 to March 2020. They were all female, aged from 54 to 76 years (average, 66 years). There were 2 transverse fractures and one short oblique fracture; all of them had knee varus deformity. The Hospital for Special Surgery (HSS) scores averaged 37.6 (from 28 to 50) for the left knee and 28.3 (from 22 to 39) for the right knee. One-stage TKA was performed for the articular surface while ORIF for the right tibial stress fracture for all patients. Recorded were fracture union time, HSS knee score and range of articular motion.Results:The 3 patients were followed up for 25 to 44 months (average, 32 months).The fracture union time ranged from 4 to 7 months (average, 5 months). The last follow-ups revealed no such complications as prosthesis loosening, peri-prosthesis osteolysis or joint instability. Knee varus deformity was corrected in all patients. The HSS knee scores at the last follow-up averaged 89.6 (from 88 to 91) for the left knee and 88.3 (from 85 to 90) for the right knee.Conclusion:In the treatment of knee osteoarthritis complicated with tibial stress fracture, one-stage TKA combined with ORIF can restore the function of knee joint, leading to fine curative effects.
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Objective To investigate the effect of Dexamethasone (Dex) on the proliferation and apoptosis of osteoblasts in vitro and to explore its underlying mechanism.Methods Osteoblasts were acquired by primary culturing from new born SD rats.The inverted microscope was used to observe the cellular appearance.The cells were identified by alkaline phosphatase staining and alizarin red staining.The third generation osteoblasts were divided into four groups.Cells were incubated with different concentrations (0,10-8 mol/L,10-7 mol/L,10-6 mol/L) of dexamethasone for 12 hours,24 and 48 hours.Cell Counting Kit-8 was performed to evaluate the inhibitory effect on cell proliferation.The apoptosis rate was analyzed by flow cytometry with Annexin Ⅴ-FITC/PI double staining.The fluorescence microscopy was used to test the nuclear alteration and the expression of caspase-3.Western blot assay was applied to detect the expression of Bcl-2,Bad,caspase-3 and phosphorylated Akt.One-Way analysis of variance was used to determine the difference between groups.LSD-t was used to compare the difference between any two groups.Results Com-pared with the control group,dexamethasone at dose of 10-8 mol/L,10-7 mol/L and 10-6 mol/L inhibited the proliferation of osteoblasts,most evidently in 48 hours (0.980±0.028 vs 1.143±0.017,t=5.454,P＜0.05;0.798±0.057 vs 1.143±0.017,t=1 1.555,P＜0.05;0.728±0.031 vs 1.143±0.017,t=13.908,P＜0.05).Dexamethasone at dose of 10-7 mol/L and 10-6 mol/L induced apoptosis of osteoblasts at 48 hours,showing significant difference compared with control group [(9.8± 2.6)％ vs (4.1±0.8)％,t=3.508,P＜0.05;(12.4±2.6)％ vs (4.1±0.8)％,t=5.140,P＜0.05].However,10-8 mol/L of dexamethasone had no apparent effect in inducing apoptosis of osteoblasts [(4.9±1.2)％ vs (4.1±0.8)％,t=0.470,P ＞0.05].The immunofluorescene staining result showed that the expression of caspase-3 protein was significantly increased in 10-7 mol/L and 10-6 mol/L dex group (t=4.320,8.475,P＜0.05).The Western blotting results showed that dexamethasoneat the concentration of 10-7 mol/L,10-6 mol/L could significantly increase the expression of Bad and caspase-3 and down-regulate the expression of Bcl-2 and p-Akt.The expression of Bcl-2 was markedly reduced by 53.8％,78.4％ (t=4.019,5.988;P＜0.05),The expression of p-Akt decreased by 37％,49.6％ (t=2.067,3.491;P＜0.05),the expression of Bad protein increased by 276.9％ and 334.8％ respectively (t=7.342,8.872;P＜0.05),the expression of caspase-3 protein were increased by 138.0％ and 193.9％ (t=5.510,7.750;P＜0.05).Conclusion Dexamethasone is capable of inhibiting the proliferation of osteoblast,as well as augmenting the apoptosis.The mechanism of this process is probably related to reduction of the level of Bcl-2 expressionand up-regulation the expression of Bad,caspase-3 with the effects of inhibiting the PI3K/Akt signaling pathway.
ABSTRACT
BACKGROUND:Osteoblasts with high purity and activity are essential for bone metabolism research. OBJECTIVE:To explore a simple and effective culturing method of primary osteoblasts. METHODS:Osteoblasts were isolated from the parietal and frontal bones of newborn Sprague-Dawley rats using trypsin and collagenase digestion and tissue explant method. The morphology of osteoblasts was observed by inverted phase contrast microscope and transmission electron microscope;the cells was counted to draw the growth curve;the osteoblasts were identified by alkaline phosphatase BCIP/NBT staining and alizarin red staining. RESULTS AND CONCLUSION:The cells showed spindle, triangle or polygon shapes, having two or three protrusions. There were abundant mitochondria and endoplasmic reticulum under electron microscope, which presented the typical characteristics of osteoblasts. The cell growth was slow intially, accelerating at the 3rd day, and peaking at the 7th day. The cells were highly positive for alkaline phosphatase staining and were stained orangered through the alizarin red staining. To conclude, the cells isolated using enzymatic digestion combined with tissue explant method exhibit the typical characteristics and functions of osteoblasts, and this method is an ideal way to culture primary osteoblasts.