Sophocarpine attenuates wear particle-induced implant loosening by inhibiting osteoclastogenesis and bone resorption via suppression of the NF-κB signalling pathway in a rat model.

BACKGROUND AND PURPOSE: Aseptic prosthesis loosening, caused by wear particles, is one of the most common causes of arthroplasty failure. Extensive and over-activated osteoclast formation and physiological functioning are regarded as the mechanism of prosthesis loosening. Therapeutic modalities based on inhibiting osteoclast formation and bone resorption have been confirmed to be an effective way of preventing aseptic prosthesis loosening. In this study, we have investigated the effects of sophocarpine (SPC, derived from Sophora flavescens) on preventing implant loosening and further explored the underlying mechanisms. EXPERIMENTAL APPROACH: The effects of SPC in inhibiting osteoclastogenesis and bone resorption were evaluated in osteoclast formation, induced in vitro by the receptor activator of NF-κB ligand (RANKL). A rat femoral particle-induced peri-implant osteolysis model was established. Subsequently, micro-CT, histology, mechanical testing and bone turnover were used to assess the effects of SPC in preventing implant loosening. KEY RESULTS: In vitro, we found that SPC suppressed osteoclast formation, bone resorption, F-actin ring formation and osteoclast-associated gene expression by inhibiting NF-κB signalling, specifically by targeting IκB kinases. Our in vivo study showed that SPC prevented particle-induced prosthesis loosening by inhibiting osteoclast formation, resulting in reduced periprosthetic bone loss, diminished pseudomembrane formation, improved bone-implant contact, reduced bone resorption-related turnover and enhanced stability of implants. Inhibition of NF-κB signalling by SPC was confirmed in vivo. CONCLUSION AND IMPLICATIONS: SPC can prevent implant loosening through inhibiting osteoclast formation and bone resorption. Thus, SPC might be a novel therapeutic agent to prevent prosthesis loosening and for osteolytic diseases.

PTH[1-34] improves the effects of core decompression in early-stage steroid-associated osteonecrosis model by enhancing bone repair and revascularization.

Steroid-associated osteonecrosis (SAON) might induce bone collapse and subsequently lead to joint arthroplasty. Core decompression (CD) is regarded as an effective therapy for early-stage SAON, but the prognosis is unsatisfactory due to incomplete bone repair. Parathyroid hormone[1-34] (PTH[1-34]) has demonstrated positive efficacy in promoting bone formation. We therefore evaluated the effects of PTH on improving the effects of CD in Early-Stage SAON. Distal femoral CD was performed two weeks after osteonecrosis induction or vehicle injection, with ten of the ON-induced rabbits being subjected to six-week PTH[1-34] treatment and the others, including ON-induced and non-induced rabbits, being treated with vehicle. MRI confirmed that intermittent PTH administration improved SAON after CD therapy. Micro-CT showed increased bone formation within the tunnel. Bone repair was enhanced with decreased empty osteocyte lacunae and necrosis foci area, resulting in enhanced peak load and stiffness of the tunnel. Additionally, PTH enlarged the mean diameter of vessels in the marrow and increased the number of vessels within the tunnels, as well as elevated the expression of BMP-2, RUNX2, IGF-1, bFGF and VEGF, together with serum OCN and VEGF levels. Therefore, PTH[1-34] enhances the efficacy of CD on osteogenesis and neovascularization, thus promoting bone and blood vessels repair in the SAON model.

In vitro and in vivo evaluation of vancomycin-loaded PMMA cement in combination with ultrasound and microbubbles-mediated ultrasound.

Ultrasound (US) has been used to increase elution of antibiotic from an antibiotic-loaded poly(methyl methacrylate) (PMMA) bone cement (ALBC). We aimed to further investigate whether microbubbles-mediated US (US + MB) facilitate elution of vancomycin (VAN) from cylindrical specimens and enhance the activity of the eluted antibiotic against Staphylococcus aureus (S. aureus) in vitro. The study groups comprised cylindrical bone cement fabricated with VAN (VAN), ALBC using US (VAN + US), and ALBC using MB-mediated US (VAN + US + MB). We also carried out an in vivo study involving the activity of VAN from cylindrical cement implanted in tibiae of New Zealand white rabbits inoculated with S. aureus. We found that (1) in vitro, elution from VAN + US + MB cylinders was significantly higher than from either the VAN or VAN + US specimens; (2) the activity of the eluted VAN from the VAN + US + MB cylinders against planktonic S. aureus was significantly higher than from either the control or VAN or VAN + US specimens; and (3) in the rabbits, the activity of the eluted VAN from the VAN + US + MB cylinders against S. aureus was significantly higher than from either the control or VAN or VAN + US specimens. The present results suggest that VAN-loaded PMMA cement irradiated with MB-mediated US may have a role in controlling prosthetic joint infection.

Does hydroxyapatite coating have no advantage over porous coating in primary total hip arthroplasty? A meta-analysis.

There are some arguments between the use of hydroxyapatite and porous coating. Some studies have shown that there is no difference between these two coatings in total hip arthroplasty (THA), while several other studies have shown that hydroxyapatite has advantages over the porous one. We have collected the studies in Pubmed, MEDLINE, EMBASE, and the Cochrane library from the earliest possible years to present, with the search strategy of "(HA OR hydroxyapatite) AND ((total hip arthroplasty) OR (total hip replacement)) AND (RCT* OR randomiz* OR control* OR compar* OR trial*)". The randomized controlled trials and comparative observation trials that evaluated the clinical and radiographic effects between hydroxyapatite coating and porous coating were included. Our main outcome measurements were Harris hip score (HHS) and survival, while the secondary outcome measurements were osteolysis, radiolucent lines, and polyethylene wear. Twelve RCTs and 9 comparative observation trials were included. Hydroxyapatite coating could improve the HHS (p < 0.01), reduce the incidence of thigh pain (p = 0.01), and reduce the incidence of femoral osteolysis (p = 0.01), but hydroxyapatite coating had no advantages on survival (p = 0.32), polyethylene wear (p = 0.08), and radiolucent lines (p = 0.78). Hydroxyapatite coating has shown to have an advantage over porous coating. The HHS and survival was duration-dependent-if given the sufficient duration of follow-up, hydroxyapatite coating would be better than porous coating for the survival. The properties of hydroxyapatite and the implant design had influence on thigh pain incidence, femoral osteolysis, and polyethylene wear. Thickness of 50 to 80 µm and purity larger than 90% increased the thigh pain incidence. Anatomic design had less polyethylene wear.

Microbubble injection enhances inhibition of low-intensity pulsed ultrasound on debris-induced periprosthetic osteolysis in rabbit model.

We determined whether the addition of microbubbles enhances the effect of low-intensity pulsed ultrasound (LIPUS) on bone-implant integration in an early-stage osteolysis model. The bone canals were injected with titanium particles before implantation to establish the periprosthetic osteolysis model. Before ultrasonic therapy, the microbubble-enhanced LIPUS group (GTi-Us-Mb) received an intra-articular injection of microbubbles. Biomechanical testing revealed that GTi-Us-Mb had significantly greater fixation strength than the LIPUS group (GTi-Us). Distal periprosthetic bone mineral density was also higher in GTi-Us than in the Ti group (GTi), but no significant increase was detected after administration of microbubbles. Histomorphometric analyses revealed that bone formation around the implant in GTi-Us was enhanced by the addition of microbubbles in GTi-Us-Mb. Taken together, our data indicate that microbubble injection enhances the inhibitory effect of LIPUS on debris-induced osteolysis and further strengthens the mechanical fixation of implants in an early-stage osteolysis model in vivo.

Cartilage oligomeric matrix protein gene multilayers inhibit osteogenic differentiation and promote chondrogenic differentiation of mesenchymal stem cells.

There are still many challenges to acquire the optimal integration of biomedical materials with the surrounding tissues. Gene coatings on the surface of biomaterials may offer an effective approach to solve the problem. In order to investigate the gene multilayers mediated differentiation of mesenchymal stem cells (MSCs), gene functionalized films of hyaluronic acid (HA) and lipid-DNA complex (LDc) encoding cartilage oligomeric matrix protein (COMP) were constructed in this study via the layer-by-layer self-assembly technique. Characterizations of the HA/DNA multilayered films indicated the successful build-up process. Cells could be directly transfected by gene films and a higher expression could be obtained with the increasing bilayer number. The multilayered films were stable for a long period and DNA could be easily released in an enzymatic condition. Real-time polymerase chain reaction (RT-PCR) assay presented significantly higher (p<0.01) COMP expression of MSCs cultured with HA/COMP multilayered films. Compared with control groups, the osteogenic gene expression levels of MSCs with HA/COMP multilayered films were down-regulated while the chondrogenic gene expression levels were up-regulated. Similarly, the alkaline phosphatase (ALP) staining and Alizarin red S staining of MSCs with HA/COMP films were weakened while the alcian blue staining was enhanced. These results demonstrated that HA/COMP multilayered films could inhibit osteogenic differentiation and promote chondrogenic differentiation of MSCs, which might provide new insight for physiological ligament-bone healing.

Effects of cartilage oligomeric matrix protein on bone morphogenetic protein-2-induced differentiation of mesenchymal stem cells.

OBJECTIVE: To investigate the effect of overexpression of cartilage oligomeric matrix protein (COMP) on bone morphogenetic protein-2 (BMP-2) induced osteogenic and chondrogenic differentiation of mesenchymal stem cells (MSCs). In this study, we used liposomes to transfect MSCs with plasmid encoding COMP and then induced the transfected MSCs to differentiate in osteogenic and chondrogenic differentiation media containing BMP-2. METHODS: MSCs transfected with plasmid DNA encoding recombinant human COMP were induced to differentiate into osteocytes and chondrocytes by BMP-2. Real-time polymerase chain reaction (PCR) assays of osteogenesis-related markers (collagen type I alpha 1, runt-related transcription factor 2, osteopontin, bone gla protein) and chondrogenesis-related markers (collagen type II alpha 1, sry-related high-mobility group box 9, Aggrecan) was performed to evaluate the process of cell differentiation. Cell differentiation was evaluated by alkaline phosphatase (ALP) and Alizarin red S stains for osteogenic differentiation and alcian blue staining for chondrogenic differentiation. RESULTS: Real-time PCR assay showed significantly greater COMP expression by MSCs when COMP gene had been transfected into the cells (P < 0.01). Overexpression of COMP down-regulated expression of osteogenesis-related markers and up-regulated expression of chondrogenesis-related markers. ALP staining and Alizarin red S staining were weakened, whereas alcian blue staining was enhanced. CONCLUSION: Overexpression of COMP inhibits BMP-2-induced osteogenic differentiation and promotes BMP-2-induced chondrogenic differentiation. These findings may provide new insights for cartilage tissue engineering. The experiments in the present study were all in vitro, which has potential limitations. Further in vivo studies to investigate the effects of COMP in animal models are necessary, which will be the next step in our research.

Microbubble-mediated ultrasound enhances the lethal effect of gentamicin on planktonic Escherichia coli.

Previous research has found that low-intensity ultrasound enhanced the lethal effect of gentamicin on planktonic E. coli. We aimed to further investigate whether microbubble-mediated low-intensity ultrasound could further enhance the antimicrobial efficacy of gentamicin. The planktonic E. coli (ATCC 25922) was distributed to four different interventions: control (GCON), microbubble only (GMB), ultrasound only (GUS), and microbubble-mediated ultrasound (GMUS). Ultrasound was applied with 100 mW/cm(2) (average intensity) and 46.5 KHz, which presented no bactericidal activity. After 12 h, plate counting was used to estimate the number of bacteria, and bacterial micromorphology was observed with transmission electron microscope. The results showed that the viable counts of E. coli in GMUS were decreased by 1.01 to 1.42 log10 CFU/mL compared with GUS (P < 0.01). The minimal inhibitory concentration (MIC) of gentamicin against E. coli was 1 µ g/mL in the GMUS and GUS groups, lower than that in the GCON and GMB groups (2 µ g/mL). Transmission electron microscopy (TEM) images exhibited more destruction and higher thickness of bacterial cell membranes in the GMUS than those in other groups. The reason might be the increased permeability of cell membranes for gentamicin caused by acoustic cavitation.

Ten versus five polymorphonuclear leukocytes as threshold in frozen section tests for periprosthetic infection: a meta-analysis.

We objectively appraised available evidence regarding the threshold for the number of polymorphonuclear leukocytes required in frozen section tests used to diagnose periprosthetic infection. Pooled summary estimates for sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio (OR) were compared for ten and five polymorphonuclear leukocytes per high power field as the threshold. The total cohort included 1011 patients and the rate of infection was 19.2%. Although there was no difference in sensitivity or diagnostic OR, specificity was significantly higher for ten than for five polymorphonuclear leukocytes per high power field (p=0.007) In sum, a threshold of 10 polymorphonuclear leukocytes is better for diagnosing periprosthetic infections.

Gallic acid induces the apoptosis of human osteosarcoma cells in vitro and in vivo via the regulation of mitogen-activated protein kinase pathways.

To examine the antitumor effects of gallic acid (GA) on osteosarcoma, two human osteosarcoma cell lines U-2OS and MNNG/HOS were treated by GA and subjected to cell proliferation and apoptosis assays. In addition, MNNG/HOS xenograft tumors were established in nude BALB/c mice to evaluate the anticancer capacity of GA in vivo. The results showed that GA inhibited the proliferation and induced the apoptosis of osteosarcoma cells, accompanied by the upregulation of p-38 activation and the downregulation of c-Jun N-terminal kinase (JNK) and extracellular signal regulated kinase (ERK1/2) activation. Additionally, p38 MAPK inhibitor abrogated GA-induced growth inhibition of osteosarcoma cells, whereas JNK or ERK1/2 inhibitors sensitized osteosarcoma cells to GA-induced growth inhibition. In vivo studies further showed that GA administration decreased xenograft tumor growth in a dose-dependent manner. Immunohistochemistry analysis demonstrated the downregulation of PCNA and CD31 expression and upregulation of apoptosis in MNNG/HOS tumor tissues following GA treatment. This study demonstrates the antitumor efficacy of GA for osteosarcoma that is mediated by the modulation of cell proliferation, apoptosis, and angiogenesis. Our findings suggest that GA could be a potent agent for osteosarcoma intervention.

Low-intensity pulsed ultrasound (LIPUS) may prevent polyethylene induced periprosthetic osteolysis in vivo.

We investigated the effect of local low-intensity pulsed ultrasound (LIPUS) on polyethylene debris induced periprosthetic osteolysis. The periprosthetic osteolysis model was made by injecting endotoxin-free pure polyethylene particles into the distal part of the femur canal and inserting a stainless steel plug into this femur. The effects of polyethylene and LIPUS were assessed histologically and by the shear strength test and periprosthetic bone mineral density (BMD) test. Sixteen rabbits received a stainless steel plug on one side and both polyethylene and a stainless steel plug on the other side. Three months later, the side that received polyethylene showed periprosthetic osteolysis. Subsequently, another 16 rabbits received polyethylene plus local LIPUS (200 mW/cm(2) for 20 min daily) on one side and polyethylene alone on the other side. Three months later, LIPUS effectively prevented the periprosthetic osteolysis caused by polyethylene in this rabbit model.

[Effects of carbon monoxide inhalation on severe limb ischemia/reperfusion injury and its damages lead to shock].

OBJECTIVE: To study the protective effect of carbon monoxide (CO) inhalation on the serious limb ischemia/reperfusion (I/R) injury, and which effects caused to shock in rats. METHODS: 36 SD rats were randomly divided into I/R, I/R + CO (RC), sham operation (S) groups. I/R injury models were made by the occlusion of the femoral artery for 8 h and the reperfusion for 12 h, 10 d. Before reperfusion of 2 h, RC group started to breathe medical air containing CO (the volume fraction of CO: 0.075%) continuously, until after reperfusion for 4 h, a total of inhalation 6 h. S, I/R groups exposed to air, breathe freely. Caudal artery pressures (CAP), ten days survival rate, serum lactate dehydrogenase (LDH) and creatine kinase (CK) activity, limb wet - to - dry weight ratio (W/D) and the pathologic changes of limb were observed. RESULTS: Once the reperfusion started, the CAP decreased rapidly in I/R group, and the mean reduced to(5.3259 +/- 0.3832) kPa when reperfusion for 8 h. Compared to I/R group, the CAP decreased slower and smaller in RC group, moreover, its mean reduced to (8.3300 +/- 0.4224) kPa when reperfusion for 8 h. The 10 d survival rate in I/R group was that 8 rats died all between reperfusion for 13 - 20 h. Only 1 rat died in RC group and the other 7 rats were still alive when reperfusion for 10 d. Compared to I/R group, the pathological features of the ischemic limb were significant ly improved, and the figures of W/D, serum LDH and CK value were remarkable lower in RC group (P < 0.05). CONCLUSION: Inhaling exogenous low-dose CO has a reverse regulation in the blood pressure decline caused by serious limb I/R injury in rats. And at the same time, it can effectively prevent the occurrence of shock, reduce physical damage, significantly increase the survival rate of animals.

The effect of injection volume on disc degeneration in a rat tail model.

STUDY DESIGN: A prospective study to compare the effects of injection of various doses of phosphate-buffered saline (PBS) solution into the intervertebral disc. OBJECTIVE: To evaluate the effect of injection volume on disc degeneration in a rat tail-disc model. SUMMARY OF BACKGROUND DATA: There are many studies on disc degeneration models induced by needle injection. Recently, novel treatments for disc degeneration have been developed that are administered by injection. However, it is unknown whether injection volume affects disc degeneration. METHODS: A total of 180 Sprague Dawley rats were randomized into five groups and injected with 0(control), 1.0, 2.0, 2.5, or 3.0 µL of PBS solution. Discs were harvested at weeks 1, 2, and 4 after injection and were evaluated using radiography, histology, and biochemistry (glycosaminoglycan, hydroxyproline, and water content). RESULTS: No significant differences in radiography, biochemistry, or histology were observed at any of the three sampling times between the 1.0, 2.0 µL groups and the control. The 2.5 and 3.0 µL groups exhibited significant decrease in radiographic disc height index and water content since week 2. The glycosaminoglycan content of 2.5 µL group decreased significantly by week 4 and that of 3.0 µL group decreased at weeks 2 and 4. Significant hydroxyproline content decrease was only observed for 3.0 µL group during week 4. Significantly higher histologic score was observed in 3.0 µL group since week 1 and 2.5 µL group since week 2. The three parameters of 3.0 µL group indicated more severe disc degeneration than those of 2.5 µL group, particularly during week 4. CONCLUSION: When the volume of PBS injected into the rat tail-disc exceeded a threshold, it rapidly exhibited degenerative changes according to radiographic, biochemical, and histologic analysis. The degenerative changes were dose-dependent and increased as the dose increased.

Effects of diallyl sulphide in chondrocyte and cartilage in experimental osteoarthritis in rabbit.

Diallyl sulphide (DAS) is known for its antioxidant, anticancer and detoxifying properties. The aim of this study was to investigate the effect of DAS on rabbit articular chondrocytes and cartilage in experimental osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT). DAS inhibited matrix metalloproteinase-1 (MMP-1), MMP-3 and MMP-13 expression in interleukin-1beta (IL-1ß)-induced chondrocytes. In an in vivo study, DAS ameliorated cartilage degradation as assessed by morphological and histological examination. Messenger RNA expression of MMP-1, MMP-3, MMP-13 and IL-1ß was inhibited by DAS in cartilage. In addition, DAS increased the collagen II level in cartilage. The results suggest that DAS may protect cartilage in the development of OA.

Anti-arthritic effects of chlorogenic acid in interleukin-1ß-induced rabbit chondrocytes and a rabbit osteoarthritis model.

Cartilage degradation is one of the pathological changes of osteoarthritis (OA), and accumulating evidence suggests an excess of matrix metalloproteinases (MMPs) plays a role in this cartilage breakdown. Here, we investigated the effects of chlorogenic acid (CGA) on the mRNA and protein expression of MMPs in interleukin (IL)-1ß-induced rabbit chondrocytes and evaluated the in vivo effects of CGA in experimental OA induced by anterior cruciate ligament transection (ACLT) in rabbits. Using quantitative real-time PCR and ELISA to investigate the expression levels of MMP-1, MMP-3, MMP-13, and tissue inhibitors of metalloproteinase-1(TIMP-1) in IL-1ß-induced rabbit chondrocytes, we showed that CGA inhibits the expression of these MMPs while increasing TIMP-1 expression, at both the mRNA and protein levels. In addition, IL-1ß-induced activation of nuclear factor kappa B (NF-κB) and the degradation of inhibitor of κB (IκB)-α were suppressed by CGA. In rabbits, CGA decreased cartilage degradation as assessed by morphological and histological analyses. The down-regulation of MMP-1, MMP-3, and MMP-13 expression and up-regulation of TIMP-1 expression were also detected in CGA-treated cartilage compared with vehicle-treated cartilage, confirming these findings in an in vivo model. Taken together, these findings indicate that CGA may be considered as a possible candidate agent in the treatment of OA.

Increased serum concentrations of visfatin and its production by different joint tissues in patients with osteoarthritis.

BACKGROUND: The goal of this study was to investigate the distribution of visfatin in paired serum and synovial fluid (SF) samples from patients with osteoarthritis (OA), and in serum from healthy controls. In addition, we wished to determine the potential sources of visfatin in joint tissue. METHODS: Twenty-three patients with OA requiring total knee arthroplasty (TKA), 17 healthy subjects and ten donors requiring amputation were included in the study. Concentrations of visfatin in serum and SF were analyzed using an enzyme-linked immunosorbent assay (ELISA). The concentration of visfatin was also measured in conditioned media from cultured joint tissues. RESULTS: We found serum visfatin concentrations to be higher in patients with OA compared to healthy controls (p<0.05), and SF-visfatin concentrations exceeded those in paired serum (p=0.004). In addition, infrapatellar fat pad and synovium were important sources of visfatin, while osteophytes released largest amounts of visfatin. Therefore, osteophytes can be considered a major source of visfatin in the knee joint in patients with OA. CONCLUSIONS: These results suggest that visfatin may be involved in the pathophysiology of OA and may have local effects in the joint during the process of OA.

[Carbon monoxide inhalation protects against limb ischemia/reperfusion injury].

OBJECTIVE: To study the protective effect of carbon monoxide(CO) inhalation in the limb ischemia/reperfusion (I/R) injury of rats. METHODS: Forty-four Sprague-Dawley rats were randomly divided into three groups: S, I/R and RC groups. I/R injury model was made by the occlusion of the femoral artery for four hours and the reperfusion for forty-eight hours. RC group was exposed to medical air mixed CO (the volume fraction of CO: 0.05%) during limb reperfusion in rats. The other two groups were exposed to the routine air. Gross morphology of the ischemic limb, wet-to-dry weight ratio (W/D), and skeletal muscle histopathology were observed. The apoptosis index and expression levels of Bax and Bcl-2 in the muscle were assessed with Flow Cytometry. The activities of serum lactate dehydrogenase (LDH) and creatine kinase (CK) were tested by Automatic Biochemical Analyzer. RESULTS: Compared to I/R group, W/D, serum LDH and CK activities, the apoptosis index and Bax expression level in the muscle were all significantly decreased, the Bcl-2 expression level was significantly increased, gross morphology of the ischemic limb and muscle histopathology were obviously improved in RC group. CONCLUSION: Inhaling exogenous CO can attenuate limb I/R injury.

Leptin plays a catabolic role on articular cartilage.

Leptin has been shown to play a crucial role in the regulation of body weight. There is also evidence that this adipokine plays a key role in the process of osteoarthritis. However, the precise role of leptin on articular cartilage metabolism is not clear. We investigate the role of leptin on articular cartilage in vivo in this study. Recombinant rat leptin (100 µg) was injected into the knee joints of rats, 48 h later, messenger RNA (mRNA) expression and protein levels of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), cathepsin D, and collagen II from articular cartilage were analyzed by real-time quantitative polymerase chain reaction (PCR) and western blot. Two important aggrecanases ADAMTS-4 and -5 (a disintegrin and metalloproteinase with thrombospondin motifs 4 and 5) were also analyzed by real-time quantitative PCR. Besides, articular cartilage was also assessed for proteoglycan/GAG content by Safranin O staining. Leptin significantly increased both gene and protein levels of MMP-2, MMP-9, cathepsin D, and collagen II, while decreased bFGF markedly in cartilage. Moreover, the gene expression of ADAMTS-4 and -5 were markedly increased, and histologically assessed depletion of proteoglycan in articular cartilage was observed after treatment with leptin. These results strongly suggest that leptin plays a catabolic role on cartilage metabolism and may be a disadvantage factor involve in the pathological process of OA.

Enhanced anticancer effect of gemcitabine by genistein in osteosarcoma: the role of Akt and nuclear factor-kappaB.

Genistein, a nontoxic flavonoid compound, has potent antitumor activity in various cancer cell lines. This study was designed to investigate whether combination therapy with gemcitabine and genistein enhances antitumor efficacy in osteosarcoma cell lines (MG-63 and U2OS). Our results show that significant reduction in cell viability and corresponding induction of apoptosis were observed with combination treatment in both cell lines. On the molecular level, we found that gemcitabine alone can activate nuclear factor kappaB (NF-kappaB) in osteosarcoma, suggesting the potential mechanism of acquired chemoresistance. In contrast, genistein reversed the cancer's resistance to gemcitabine through the downregulation of NF-kappaB activity and the suppression of Akt. These findings suggest that the combination of gemcitabine and genistein enhanced the antitumor efficacy by abrogating the Akt/NF-kappaB pathway. The marked ability to induce apoptosis with a combination of gemcitabine and genistein suggests that this could be a rational and novel approach for osteosarcoma preclinical and clinical trials.

Variation patterns of two degradation enzyme systems in articular cartilage in different stages of osteoarthritis: regulation by dehydroepiandrosterone.

BACKGROUND: Osteoarthritis (OA) is a multifactorial degenerative joint disease in which the cartilaginous matrix of the articular joint is destroyed in a continuous process. We evaluated mRNA levels of cysteine proteinases/cystatin C system and urokinase plasminogen activator/plasminogen activator inhibitor-1 (uPA/PAI-1) system in articular cartilage and regulation by dehydroepiandrosterone (DHEA) in different stages of osteoarthritis (OA). METHODS: One hundred and eight rabbits underwent anterior cruciate ligament transection (ACLT) in the left knee, 54 received weekly intra-articular injections of DHEA (100 micromol/l) 0.3 ml 3 weeks after transaction as DHEA group. Thirty-six rabbits (18 from 2 groups respectively) were euthanized 6, 9, and 12 weeks after ACLT. All left knee joints were assessed by gross morphology and histology, meantime the gene expression from articular cartilage was analyzed. RESULTS: Cathepsins and uPA gene increased significantly 6 weeks and reached peak in the 9th week, while declined to extremely low levels 12 weeks after ACLT. Cystatin C decreased accompanied by OA progression, while PAI-1 expressed in the same trend with uPA. Additionally, these 2 enzyme systems were markedly suppressed by DHEA 6 and 9 weeks after ACLT but not in the 12th week. CONCLUSION: The variation of these 2 enzyme systems was closely related to the progression of OA, and could be regulated by DHEA especially in the early and medium stages of OA.