CircSmg5 stimulates the osteogenic differentiation of bone marrow mesenchymal stem cells by targeting the miR-194-5p/Fzd6 axis and beta-catenin signaling.

BACKGROUND: Osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) is closely associated with bone diseases. Circular RNAs are reported to be involved in BMSC differentiation. CircSmg5 (circ_0001145) has been identified to be downregulated in an osteoporosis mouse model. In this study, we aimed to explore the function and regulatory mechanism of circSmg5 in BMSC osteogenic differentiation. METHODS: The Alizarin Red staining and alkaline phosphatase staining assays were performed to explore the osteogenic differentiation of BMSCs. The interaction between circ_0001145, miR-194-5p, and frizzled class receptor 6 (Fzd6) was analyzed by luciferase reporter assay. The nuclear translocation of ß-catenin was assessed using immunofluorescence staining. RESULTS: CircSmg5 is in stable circular structure. CircSmg5 expression was elevated in the process of BMSC osteogenic differentiation. CircSmg5 overexpression promoted the osteogenic differentiation of BMSCs. CircSmg5 bound with miR-194-5p, whose expression was decreased in the osteogenic differentiation of BMSCs. MiR-194-5p directly targeted the 3'UTR of Fzd6. The mRNA and protein levels of Fzd6 were positively modulated by circSmg5 and negatively regulated by miR-194-5p in BMSCs. CONCLUSION: CircSmg5 was demonstrated to promote the BMSC osteogenic differentiation by targeting the miR-194-5p/Fzd6 axis to activate the Wnt/ß-catenin signaling.

A prospective comparative study of hip resurfacing arthroplasty and large-diameter head metal-on-metal total hip arthroplasty in younger patients-a minimum of five year follow-up.

INTRODUCTION: Both hip resurfacing arthroplasty (HRA) and large-diameter head metal-on-metal total hip arthroplasty (LDH MoM THA) are generally used for young and active patients. A number of comparative studies of HRA and total hip arthroplasty have been published in the literature. However, studies that have compared HRA with LDH MoM THA are rare. The purpose of this study is to compare the mid-term results of HRA with those of LDH MoM THA in young patients. PATIENTS AND METHODS: Between 2007 and 2011, 68 patients were enrolled in the study and randomized into two groups: HRA group (28 hips) and LDH MoM THA group (40 hips). Peri-operative data including blood loss, surgery duration, size of the implant, and post-operative complications were recorded. All patients were assessed clinically and radiologically at six weeks; one, three and five years; and at the time of final review. Functional outcome were assessed using Harris hip (HHS), University of California Los Angeles (UCLA) and Oxford hip (OHS) scores. The mean follow-up for all patients was 7.4 years (5 to 9). RESULTS: Patient groups matched similarly in age, percent female, body mass index, preoperative HHS, and follow-up time. No differences were observed between the two groups in blood loss or in head size or acetabular inclination angle. HRA group had significantly longer surgery duration but less blood loss. The two groups had comparable HHS, UCLA, and OHS at the latest follow-up. Major complications, such as fracture, dislocation, infection, and adverse reactions to the metal debris (ARMD) were not found in the two groups. Only one case in LDH MoM THA group underwent revision surgery due to unexplained pain. CONCLUSION: Comparison of HRA and LDH MoM THA shows similar mid-term clinical results. HRA may be preferable due to the well-preserved bone stock and restoration of the native anatomy. LDH MoM THA may be used with caution due to the excessive metal ion release.

Transcriptome changes during TNF-α promoted osteogenic differentiation of dental pulp stem cells (DPSCs).

Dental pulp stem cells (DPSCs), due to the ease of isolation and their capacities of multi-lineage differentiation, are considered as attractive resources for regenerative medicine. In a previous study, we showed that TNF-α promoted the osteogenic differentiation of DPSCs via the NF-κB signaling pathway. However, the mechanisms of such differentiation were largely unknown. Here, we examined the gene expression profiles between undifferentiated, partially differentiated and fully differentiated DPSCs induced by TNF-α by performing the next-generation sequencing technique (RNA-Seq). Our results revealed a continuous transition of the transcriptome changes during TNF-α promoted osteogenic differentiation of DPSC. Bioinformatics analysis revealed a relatively general to specific transformation of the involved signaling pathways from the early to late stages of differentiation. Gene regulatory network analysis highlighted novel, key genes that are essential for osteogenic differentiation at different time points. These results were further validated by quantitative RT-PCR, confirming the high reliability of the RNA-Seq. Our data therefore will not only provide novel insights into the molecular mechanisms that drive the osteogenic differentiation of DPSCs, but also promote the studies of bone tissue engineering that utilizes DPSCs as a crucial resource.

Gender differences of venous thromboembolism risk after total hip and total knee arthroplasty: a meta-analysis.

We performed a meta-analysis to evaluate gender differences of venous thromboembolism (VTE) risk after total hip (THA) and total knee arthroplasty (TKA). We searched PubMed and Web of Knowledge from their beginning to 25 July 2015. Pooled odds ratio (OR) and 95 % confidence interval (CI) for VTE risk were calculated. Twenty studies with 7,892,585 patients were included in our study. The VTE incidence ranged from 0.27 to 61.0 %. The sex ratio (male/female) was 0.623 (3,016,648/4,839,785) in no VTE group versus 0.492 (11,926/24,226) in VTE group. The pooled OR was 1.184 (95 % CI 1.070-1.310; Z = 3.28, P = 0.001). The Begg's test (z = 1.46, P = 0.144) and the Egger's test (t = 0.58, P = 0.571), and the funnel plot suggested there was no significant publication bias. Sensitivity analysis by omitted a study with largest simple size showed the pooled OR was 1.166 (95 % CI 1.051-1.294; Z = 2.91, P = 0.004) by random-effects model. Meta-regression showed VTE risk was not related with THA and TKA incidence (t = 0.35, P = 0.732). Our meta-analysis showed female patients have slightly higher risk of VTE than male patients after THA and TKA.

Prevention of Surgical Site Infection After Ankle Surgery Using Vacuum-Assisted Closure Therapy in High-Risk Patients With Diabetes.

Patients with diabetes have a high risk of surgical site infection (SSI) after ankle surgery. The aim of the present study was to investigate the efficacy of vacuum-assisted closure (VAC) in the prevention of SSI after ankle surgery compared with the efficacy of standard moist wound care (SMWC). A retrospective study was performed of unstable ankle fractures for surgical fixation in patients with diabetes from January 2012 to December 2014. VAC and SMWC were used for surgical incision coverage. The primary outcome was the incidence of SSI, and the secondary outcomes were the length of hospital stay and crude hospital costs. The data from 76 patients were analyzed, with 22 (28.95%) in the VAC group and 54 (71.05%) in the SMWC group. The incidence of SSI was 4.6% in the VAC group compared with 27.8% in the SMWC group (chi-square 5.076; p = .024), and the crude odds ratio for SSI in the VAC group was 0.124 (95% confidence interval 0.002 to 0.938). The length of hospital stay was lower in the VAC group than in the SMWC group (12.6 ± 2.7 days and 15.2 ± 3.5 days, respectively; t = 3.122, p = .003). The crude hospital costs were also lower in the VAC group than in the SMWC group (Chinese yuan 8643.2 ± 1195.3 and 9456.2 ± 1106.3, respectively; t = 2.839, p = .006). After logistic regression analysis, the adjusted odds ratio for the total SSI rate comparing VAC and SMWC was 0.324 (95% confidence interval 0.092 to 0.804; p = .021). Compared with SMWC, VAC can decrease the SSI rate after ankle surgery in patients with diabetes. This finding should be confirmed by prospective, randomized controlled clinical trials.

Atlas of Human Skeleton Hardness Obtained Using the Micro-indentation Technique.

OBJECTIVES: Measure and systematically evaluate the distribution of microhardness in the human skeleton. METHODS: Three fresh corpses were obtained, aged 62 (male), 45 (female), and 58 years (male). Soft tissues were removed, and all axial and unilateral appendicular bones were freshly harvested. All three skeletons were examined by X-ray and computed tomography (CT) to exclude skeletal pathology. Only bones from donors with no known skeletal pathology were included in the study. Axial and unilateral appendicular skeleton bones from each of the three donors were obtained, except for ear ossicles, hyoid bone, tailbone, and 14 phalanges of the foot, for which samples were difficult to obtain. Precision bone specimens with a thickness of 3 mm, which were cut with a Buehler IsoMet 11-1280-250 low-speed diamond saw (Buehler, USA), were obtained from all important anatomic sites in a direction perpendicular to the mechanical axis of each bone. Micro-indentation (the Vickers hardness test) was performed on the surface of each specimen using a microhardness tester with a diamond indenter. Hardness value (HV) was computed for each indentation. Each bone specimen was divided into several regions of interest. Indentations were carefully made and computed. Then we analyzed the data to identify hardness distribution rules at different anatomic sites. RESULTS: In total, 5360 indentations were made in 1072 regions of interest in each donor. Hardness of the axial and appendicular bones were all inhomogeneous depending on the anatomic sites, but the distribution of microhardness followed certain rules. The mean hardness value ranged from 24.46 HV (HV = hardness value, kgf/mm2 ) for the sacrum to 53.20 HV for the shaft of the tibia. The diaphysis was harder than the metaphysis, and the proximal and distal epiphysis had lower values (8.85%- 40.39%) than the diaphysis. Among the long bone diaphyses, the tibia cortical bone (51.20 HV) was the hardest, harder than the humerus (47.25 HV), the ulna (43.26 HV), the radius (42.54 HV), and the femur (47.53 HV). However, in some anatomic sites such as the lumbar vertebra (cortical bone 32.86 HV, cancellous bone 31.25 HV), the cortical shells were sometimes not harder than the internal cancellous bones. The lumbar vertebra (32.86 HV) was harder than the cervical vertebra (28.51 HV) and the thoracic vertebra (29.01 HV). CONCLUSIONS: The distribution of microhardness in the human skeleton follows certain rules. These distribution rules could be used to predict the mechanical properties of bone and progress in this field could provide data for the basis of a new three-dimensional printing technique, which may lead to new perspectives for custom-made implants.

[Treatment of type C intercondylar fractures of distal humerus using dual plating].

OBJECTIVE: To evaluate the clinical outcome of dual plating in the treatment of humeral intercondylar type-C fractures in adults. METHODS: From June 2004 to October 2007, 38 cases of type-C distal humeral fractures were stabilised with dual plating. There were 21 males and 17 females. The average age was 43 years with a range from 21 to 71 years. According to the AO classification, 9 cases were of type C1, 17 of C2 and 12 of C3. The posterior midline approach was selected. Twenty-one cases were exposed through the trans-olecranon osteotomy, 11 through the Campbell (Van Gorder) approach, 6 through triceps sparing approach. Autogenous bone graft was performed in 5 cases because of severe comminution. RESULTS: Thirty-five patients were followed-up for 14-30 months (mean 24.2 months). At the latest follow-up, the elbow flexion averaged 119 degrees (range 90 degrees - 135 degrees ), and the loss of extension averaged 16.2 degrees (range 5 degrees - 25 degrees ). All the patients got bony healing, the average healing period was 14 weeks. The patients were evaluated using the criteria of Aitken and Rorabeek and the scores were 13 excellent, 16 good, 6 fair. Twenty-nine patients (82.9%) had a good or excellent results. Complications included 4 cases of traumatic osteoarthritis, 2 heterotopic ossification, 1 ulnar neuropathy. Infection as well as loosening or breakage of the implant was not found. CONCLUSIONS: The dual plating is able to provide rigid fixation for the humeral intercondylar fractures. In addition, it can allow early functional exercise after operation, decrease the related complications significantly, and improve the functional results.

Profiling lncRNA alterations during TNF­α induced osteogenic differentiation of dental pulp stem cells.

The multipotent and easily accessible characteristics of dental pulp stem cells (DPSCs) make them a promising target for bone tissue engineering. Long non­coding RNAs (lncRNAs) have an important role in the osteogenic differentiation of mesenchymal stem cells. Nevertheless, whether lncRNAs are involved in the osteogenic differentiation of DPSCs remains unclear. The present study examined the expression alterations of lncRNAs in tumor necrosis factor­α induced osteogenic differentiation of DPSCs. Following identification of differentially expressed lncRNAs at different time points by reverse transcription­quantitative polymerase chain reaction, profiling analysis was performed and a profile was further validated, in which lncRNA expression levels demonstrated significant upregulation. The next generation sequencing analysis identified 77 (58 upregulated and 19 downregulated) and 133 differentially expressed lncRNAs (73 upregulated and 60 downregulated) at 7 and 14 days post­treatment, respectively. In addition, 34 lncRNAs were predicted to be strongly associated with 336 mRNA transcripts that underwent significant alterations during osteogenic differentiation. The present data demonstrated that one lncRNA, X inactive specific transcript, is essential for efficient osteogenic differentiation of DPSCs by alkaline phosphatase staining. In summary, the present findings provide insight for the understanding of how non­coding RNAs are involved in regulating the osteogenic differentiation of DPSCs, which may further advance the translational studies of bone tissue engineering.

Bone Material Properties of Human Phalanges Using Vickers Indentation.

OBJECTIVE: To investigate the microhardness distribution throughout the human hand phalanges using the Vickers method, which can be used to directly evaluate the bone mechanical properties at tissue level and provide an alternative means to investigate bone quality. METHODS: The phalanges bones involved in this study were collected from three healthy donors; fresh-frozen right limbs were used. The phalanges bones were dissected and cut into 3-mm thick slices perpendicular to the long axis in the phalanges base, the phalanges shaft, and the phalanges head with a low-speed saw and then the slices were polished with sandpaper. A microindenter fitted with a Vickers indenter point was used to measure the Vickers hardness in the plantar, dorsal, medial, and lateral sites of cortical bone in metatarsal shaft and trabecular bone in the metatarsal base and head. The indentation load and dwell time was set to 50 g and 12 s for both the cortical and cancellous tissues in this study. For each site or region, five valid values were recorded and averaged as the Vickers hardness for the site or region. RESULTS: In total, 96 bone slices were harvested from the base, shaft, and head of the 15 phalanges and 1920 indentations were performed. In general, the Vickers hardness in phalanges was 34.11 ± 7.95 HV. For the 5 phalanges, the 3rd phalanx showed the highest hardness (36.74 ± 7.10 HV), closely followed by the 1st (36.46 ± 5.96 HV) and 2nd (35.28 ± 6.52 HV) phalanx. The hardness in the 4th (31.90 ± 9.15 HV) and 5th (31.19 ± 8.22 HV) phalanx were significantly lower than in the other 3 phalanges. The hardness in the phalanx shaft (38.52 ± 6.67 HV) was significantly higher than that in both the base (30.73 ± 7.46 HV) and head (30.64 ± 6.81 HV) of the phalanx (F = 300.7, P = 0.000); no statistic difference existed between the base and head of the phalanx (P = 0.996). The Vickers hardness in the proximal, middle, and distal phalanx showed statistical difference in Vickers hardness (F = 19.278, P = 0.000). The proximal phalanx showed higher Vickers hardness than the middle phalanx in the 2nd to 5th phalanges (P = 0.002). CONCLUSION: This study reported on the Vickers hardness distribution of the human phalanges bone and provides the theoretical basis of differences in hardness, which will benefit the placement of plates and screws in orthopaedic surgery and contribute to the research on ideal artificial bones and 3D-printed orthopaedic implants with inner gradient distribution of hardness.

N-acetylcysteine Attenuates Cobalt Nanoparticle-Induced Cytotoxic Effects through Inhibition of Cell Death, Reactive Oxygen Species-related Signaling and Cytokines Expression.

OBJECTIVE: Complex cobalt-chromium alloys, bearing surfaces of the second-generation metal-on-metal (MoM) hip prostheses, are subject to wear and generate cobalt nanoparticles (CoNPs). CoNPs could reduce cellular viability, activate the mitogen-activated protein kinase (MAPK) pathway and increase cell apoptosis via reactive oxygen species (ROS). However, the detailed mechanisms of ROS functioning on CoNP-mediated signaling molecules and cytotoxicity has not yet been fully demonstrated. The present study investigated the functional role of N-acetylcysteine (NAC) in reversing the activation of ROS signaling pathways triggered by CoNPs in normal mice kidney cells (TCMK-1 cells). METHODS: After being pretreated with NAC, TCMK-1 cells were treated with 300-700 µmol/L CoNPs, then, CCK-8 assay was used to verify the survival of TCMK-1 cells. Annexin V/PI staining was performed to investigate the apoptosis of TCMK-1 cells after NAC and different concentrations of CoNP treatments. In addition, western blot was performed to identify the cytokine (p-ERK, p-p38, and p-JNK) expression of the ROS-related MAPK signaling pathway. RESULTS: Apoptosis rate of TCMK-1 cells was increased obviously after different concentrations of CoNP treatment. However, TCMK-1 cells, pretreated with NAC, exhibited a significantly decreased apoptosis rate. In addition, p-ERK, p-p38, and p-JNK expressions were increased with CoNP treatment, which indicated that CoNPs could activate the MAPK pathway. Interestingly, this entire stimulated phenomenon by CoNPs was reversed with NAC treatment. CONCLUSIONS: These findings indicated that NAC could reverse CoNP-induced cytotoxicity by inhibiting ROS-induced cell death and cytokine expression. To our knowledge, this is the first report that describes how CoNP-induced cytotoxicity in TCMK-1 cells could be attenuated by anti-oxidative agents (NAC), which may function through inhibition of cell death and ROS.

Wound management with vacuum assisted closure in surgical site infection after ankle surgery.

OBJECTIVE: The aim of this study was to compare the efficacy of vacuum assisted closure (VAC) with standard moist wound care (SMWC) in surgical site infection after ankle surgery. METHODS: A prospective cohort was performed among patients with surgical site infection after ankle surgery between 2012 and 2013. The follow-up period was three month, and the efficacy end point was complete wound closure rate. RESULTS: Ninety-four patients were analyzed, with 61 patients in the VAC group and 33 in the SMWC group. The complete wound closure rate in the VAC group was higher than that in the SMWC group at 3 month follow up (90.2% Vs. 72.7%, p = 0.028). The median time to complete wound closure was 31 days (95% CI 20.2-41.8) for VAC, and 63 days (95% CI 46.9-79.1) for SMWC (χ(2) = 4.023, p = 0.045). In the superficial infection subgroup, the median times to complete wound closure were 20 days (95% CI 14.2-35.1) in the VAC group and 42 days (95% CI 35.4-69.4) in SMWC group (χ(2) = 4.331, p = 0.041). In the deep subgroup, the median times to complete wound closure were 46 days (95% CI 28.2-65.9) in the VAC group and 75 days (95% CI 43.2-79.6) in SMWC group (χ(2) = 6.475, p = 0.026). CONCLUSION: Our result showed that vacuum assisted closure was more effective than standard moist wound care in surgical site infection after ankle surgery.

Toxicity and bioactivity of cobalt nanoparticles on the monocytes.

OBJECTIVE: To explore the toxicity and biological activity of cobalt nanoparticles on the osteoclasts. Analyze the relationship between cobalt nanoparticles and osteolysis. METHODS: Monocyte-macrophages (RAW 264.7) was cultured in vitro, osteoclast-like cells were induced by lipopolysaccharides (LPS). After RAW 264.7 was induced for 24 h, Methyl Thiazolium Tetrazolium (MTT) biological toxicity test of osteoclast-like cell was preceded using Cobalt nanoparticles (set 4 concentrations: 10, 20, 50, 100 µM) and cobalt chloride (set 4 concentrations: 10, 20, 50, 100 µM) at 2, 4, 8, 24 and 48 h respectively. The relative expression of mRNA of CA II and Cat K after RAW 264.7 induction was determined by Q-PCR. RESULTS: mRNA relative expression of CA II, Cat K were reduced at multiple concentrations both cobalt nanoparticles and cobalt chloride, and was time and concentration dependent, cobalt nanoparticles are more significant than cobalt chloride group. But when the cobalt nanoparticles concentration is in 10-50 µM, the mRNA relative expression of CA II, Cat K increased. CONCLUSION: Cobalt nanoparticles have biological toxicity. At multiple concentrations, the differentiation and proliferation of osteoclasts was inhibited, but when the concentration of cobalt nanoparticles is in 10-50 µM, it has been strengthened.

HbA1c and Lower Extremity Amputation Risk in Patients With Diabetes: A Meta-Analysis.

In this meta-analysis, we aimed to assess glycosylated hemoglobin (HbA1c) level and lower extremity amputation (LEA) risk in patients with diabetes. Systematic computerized searches of the PubMed and Web of Knowledge were performed. We compared HbA1c level between groups with LEA and without LEA by meta-analysis; we also examined the dose-response relationship between HbA1c level and LEA risk. Sixteen studies were included in the meta-analysis. Eleven studies with 43,566 patients compared HbA1c between groups with and without LEA. The mean HbA1c (%) ranged from 8.3 to 12.5 in the group with LEA and from 7.4 to 11.3 in the group without LEA. The pooled weighted mean difference was 1.110 (95% confidence interval = 0.510-1.709; Z = 3.63, P = .008). The funnel plot was symmetrical, and Begg's test (z = 0.00, P = 1.000) and Egger's test (t = -0.02, P = .984) suggested no significant publication bias. Six studies with 109,933 patients included in the dose-response meta-analysis. The LEA incidence ranged from 0.3% to 14.6% between different HbA1c levels. Dose-response meta-analysis showed statistically significant association between HbA1c and LEA risk (χ(2) = 65.51, P = .000). In linear model, the odds ratio for LEA incidence was 1.229 (95% confidence interval = 1.169-1.292) for every 1% HbA1c increase. In the spline model, the odds ratio of LEA risk increased with HbA1c levels, especially when HbA1c ranged from 5% to 9%. Our meta-analysis indicates that high level of HbA1c is an important risk factor for LEA in patients with diabetes. This evidence supports the strategy for lowering glucose levels to reduce amputation in patients with diabetes.

Body mass index and knee osteoarthritis risk: a dose-response meta-analysis.

OBJECTIVE: Evidence shows obesity is an important risk factor for knee osteoarthritis (OA). However, the dose-response relationship between body mass index (BMI) and knee OA risk is unclear. The purpose of the current study is to establish a nonlinear dose-response relationship between BMI and risk of knee OA. METHODS: The electronic database of PubMed, Web of Science, and translating research into practice (TRIP) database were searched. Observational studies for BMI and knee OA risk were included. Restricted cubic splines and generalized least-squares regression methods were used to model a potential curvilinear relationship and to make a dose-response meta-analysis. RESULTS: A total of 12 studies were included in the meta-analysis. A non-linear dose-response association between BMI and risk of knee OA was significant (P = 0.001). The relative risks were 1.59 (95% CI: 1.34-1.81), 3.55 (95% CI: 2.51-5.11), and 7.45 (95% CI: 4.19-13.13) when BMI was at the point of 25, 30, and 35 kg/m(2) compared with reference (22.5 kg/m(2) , the median value of the lowest category), respectively. Non-linear dose-response association was also significant in male and female subgroup. In male subgroup, the relative risks were 1.39 (95% CI: 0.99-1.92), 3.41 (95% CI: 2.07-5.48), and 5.71 (95% CI: 3.12-9.95) when BMI was at the point of 25, 30, and 32.5 kg/m(2) compared with reference, respectively. In female subgroup, the relative risks were 1.72 (95% CI: 1.51-1.99), 3.51 (95% CI: 2.65-4.51), and 4.72 (95% CI: 3.25-6.91) compared with reference when BMI was at the point of 25, 30, and 32.5 kg/m(2) compared with reference, respectively. Modest publication bias was found in the meta-analysis. However, sensitivity analysis showed a high stability for the result. CONCLUSIONS: The meta-analysis indicated that knee OA risk increased almost exponentially according with the increase of body mass index. Knee OA prevention will benefit from weight control.

Effects of serum cobalt ion concentration on the liver, kidney and heart in mice.

OBJECTIVE: To investigate the effects of serum cobalt ion concentration on the liver, kidney and heart in mice. METHODS: Forty 4-week-old male ICR mice were randomly divided into four groups (n = 10 in each group) as follows: Group 1 (HD), high-dose cobalt chloride group (3.28 mg/kg/day); Group 2 (MD), medium-dose cobalt chloride group (1.64 mg/kg/day); Group 3 (LD), low-dose group cobalt chloride group (0.82 mg/kg/day); and Group 4 (NC), normal control group (vehicle). Cobalt chloride and normal saline were given by intraperitoneal injection once per day for 3 weeks. The body weights of the mice were recorded every 3 days to ensure the correct doses of cobalt chloride. Blood samples for testing were taken at day 4, week 1, week 2 and week 3. Serum cobalt ion concentrations were measured in all samples whereas other serum biochemical variables, including aspartate aminotransferase (AST), aspartate aminotransferase (ALT), blood urea nitrogen (BUN), creatinine (Cr), and creatine kinase (CK) were evaluated at week 1, 2 and 3. After killing the mice at week 3, the heart, liver and kidney were collected for pathological evaluation. RESULTS: Serum cobalt ion concentration was different between the groups. High-dose cobalt chloride significantly increased AST, ALT and CK concentrations, the concentrations increasing in parallel with treatment duration. Pathological evaluation showed that high-dose cobalt chloride had toxic effects on the heart and liver; however no significant effect was apparent in the kidney. CONCLUSION: High-dose cobalt ion concentration in serum has toxic effects on the heart and liver, but no significant effect on the kidney in mice.