Search

Osteoarthritis (OA) is a disease of joint degeneration and impaired function. Muscle atrophy, fatty infiltration (FI), and fibrosis are degenerative features of muscle injury and predict poor outcomes in some degenerative and exercise-related injuries. Patients with glenohumeral joint OA are usually accompanied by rotator cuff muscle degeneration, even though the rotator cuff is intact. However, the mechanism and correlation between OA and degeneration of muscles around joints are still unknown.Forty-five 12-month-old C57BL/6J mice received a single injection of monoiodoacetic acid(MIA)into the right glenohumeral joint. The sham group was injected with saline on the same day in the right glenohumeral joint. 3 and 6 weeks after the operation, gait analysis was conducted to evaluate the function of the forelimb. Then, the shoulder joint and supraspinatus muscle (SS) were collected for histological staining, RT-qPCR, and biomechanics test. Correlations between fat area fraction in muscle, percentage wet muscle weight change or OARSI score and gait analysis,/muscle mechanics tests were assessed using Pearson's correlation coefficient or Spearman's correlation coefficient.Compared with the sham group, the MIA group developed significant glenohumeral joint OA, and the SS developed significant FI and muscle atrophy. Shoulder function correlated with glenohumeral joint OA/rotator cuff muscle severity, weight loss, and FI.In mice, glenohumeral joint OA can lead to rotator cuff degeneration and inferior limb function. The small animal model could be a powerful tool to further study the potential mechanisms between glenohumeral OA and rotator cuff muscle degeneration.Basic Science Study; In-Vivo Animal Model.

Background: Fatty infiltration (FI) of the rotator cuff muscles is correlated with shoulder function and retear rates after rotator cuff repair. High-intensity interval training (HIIT) induces beige adipose tissue to express more uncoupling protein 1 (UCP1) to consume lipids. The beta-3 adrenergic receptor (β3AR) is located on adipocyte membrane and induces thermogenesis. Purpose: To test the role of HIIT in improving muscle quality and contractility in a delayed rotator cuff repair mouse model via β3AR. Study Design: Controlled laboratory study. Methods: Three-month-old C57BL/6J mice underwent a unilateral supraspinatus (SS) tendon transection with a 6-week delayed tendon repair. Mice ran on a treadmill with the HIIT program for 6 weeks after tendon transection or after delayed repair. To study the role of β3AR, SR59230A, a selective β3AR antagonist, was administered to mice 10 minutes before each exercise through intraperitoneal injection. The SS, interscapular brown adipose tissue (iBAT), and subcutaneous inguinal white adipose tissue (ingWAT) were harvested at the end of the 12th week after tendon transection and were analyzed by histology and Western blotting. Tests were performed to assess muscle contractility of the SS. Results: Histologic analysis of SS showed that HIIT prevented and reversed muscle atrophy and FI. The contractile tests showed higher contractility of the SS in the HIIT groups than in the no-exercise group. In the HIIT groups, SS, iBAT, and ingWAT all showed increased expression of tyrosine hydroxylase, UCP1, and upregulated β3AR thermogenesis pathway. However, SR59230A inhibited HIIT, suggesting that the effect of HIIT depends on β3AR. Conclusion: HIIT improved SS quality and function after delayed rotator cuff repair through a β3AR-dependent mechanism. Clinical Relevance: HIIT may serve as a new rehabilitation method for patients with rotator cuff muscle atrophy and FI after rotator cuff repair to improve postoperative clinical outcomes.

ObjectivesMetabolic syndrome (MS) comprises a constellation of symptoms that include abdominal obesity, hypertension, hyperglycaemia and dyslipidaemia. Dietary intake is a crucial environmental risk factor for MS, but the exact association between MS and egg consumption, which accounts for more than half of the daily total cholesterol intake in Chinese population, has not been previously studied. The aim of this study was to examine the correlation between dietary egg consumption and the prevalence of MS in the context of a large population.DesignA cross-sectional study.SettingsOur study was conducted in a health examination centre in China.ParticipantsParticipants who aged ≥40 years and received routine physical examinations were included for analyses.Main outcome measuresMS was diagnosed in accordance with the clinical diagnosis criteria specified in the American Heart Association Guidelines. Egg consumption was assessed by a validated semi-quantitative food frequency questionnaire.ResultsA total of 11 529 participants (46.2% women) were included in the present study. On the basis of multivariable logistic regression analysis, egg consumption was negatively associated with the prevalence of MS after adjusting for dietary energy intake (OR=0.84, 95% CI 0.76 to 0.93, p value for trend=0.001). The above findings did not change with further adjustment for other potential confounders: model 2 was further adjusted for age, body mass index and sex (based on model 1) and model 3 was further adjusted for education level, physical activity level, smoking status, alcohol use status, dietary fat intake, dietary fibre intake and nutritional supplementation (based on model 2). Consistent results were obtained from the analysis in the female subgroup but not in male subjects.ConclusionsA higher level of egg consumption was associated with a lower prevalence of MS in our study participants, and particularly in female subjects.

Objective This study was designed to evaluate the biocompatibility and osteointegrative activity of hydroxyapatite (HA)-CaTiO 3 , titanium substrate, traditional HA coating and CaTiO 3 coating via an animal experiment. Method Four types of screws (type 1: coated with HA; type 2: coated with CaTiO 3 ; type 3: coated with HA-CaTiO 3 ; type 4: untreated titanium screws) were implanted into femur bone of 48 New Zealand rabbits. Histological and mechanical investigations were employed at the end of 2, 4, 8 and 12 weeks to evaluate the material osteointegration. Results (1) All of the experimental rabbits were healthy during the experiment process. (2) Histological investigation showed fully regenerated and well integrated bone tissue surrounding the screws coated with HA, HA-CaTiO 3 and CaTiO 3 . (3) Mechanical investigation showed that the bonding strength of HA-CaTiO 3 coating was significantly higher than that of CaTiO 3 coating or titanium materials without coating, but was lower than those coated with HA. Conclusion HA-CaTiO 3 coating possesses similar admirable biocompatibility and osteointegration activity with HA coating, indicating a promising coating material for implants in orthopedics.

The distal end of the spinal cord and neuromuscular junction may develop secondary degeneration and damage following spinal cord injury because of the loss of neural connections. In this study, a rat model of spinal cord injury, established using a modified Allen's method, was injected with basic fibroblast growth factor solution via subarachnoid catheter. After injection, rats with spinal cord injury displayed higher scores on the Basso, Beattie and Bresnahan locomotor scale. Motor function was also well recovered and hematoxylin-eosin staining showed that spinal glial scar hyperplasia was not apparent. Additionally, anterior tibial muscle fibers slowly, but progressively, atrophied. nohistochemical staining showed that the absorbance values of calcitonin gene related peptide and acetylcholinesterase in anterior tibial muscle and spinal cord were similar, and injection of basic broblast growth factor increased this absorbance. Results showed that after spinal cord injury, the distal motor neurons and motor endplate degenerated. Changes in calcitonin gene related peptide and acetylcholinesterase in the spinal cord anterior horn motor neurons and motor endplate then occurred that were consistent with this regeneration. Our findings indicate that basic fibroblast growth factor can protect the endplate through attenuating the decreased expression of calcitonin gene related peptide and acetylcholinesterase in anterior horn motor neurons of the injured spinal cord.