Revealing the crucial roles of suppressive immune microenvironment in cardiac myxoma progression.

Cardiac myxoma is a commonly encountered tumor within the heart that has the potential to be life-threatening. However, the cellular composition of this condition is still not well understood. To fill this gap, we analyzed 75,641 cells from cardiac myxoma tissues based on single-cell sequencing. We defined a population of myxoma cells, which exhibited a resemblance to fibroblasts, yet they were distinguished by an increased expression of phosphodiesterases and genes associated with cell proliferation, differentiation, and adhesion. The clinical relevance of the cell populations indicated a higher proportion of myxoma cells and M2-like macrophage infiltration, along with their enhanced spatial interaction, were found to significantly contribute to the occurrence of embolism. The immune cells surrounding the myxoma exhibit inhibitory characteristics, with impaired function of T cells characterized by the expression of GZMK and TOX, along with a substantial infiltration of tumor-promoting macrophages expressed growth factors such as PDGFC. Furthermore, in vitro co-culture experiments showed that macrophages promoted the growth of myxoma cells significantly. In summary, this study presents a comprehensive single-cell atlas of cardiac myxoma, highlighting the heterogeneity of myxoma cells and their collaborative impact on immune cells. These findings shed light on the complex pathobiology of cardiac myxoma and present potential targets for intervention.

Theoretical Study on the Electrocatalytic CO2 Reduction Mechanism of Single-Atom Co Complexed Carbon-Based (Co-Nχ@C) Catalysts Supported on Carbon Nanotubes.

Electrocatalytic CO2 reduction serves as an effective strategy to tackle energy crises and mitigate greenhouse gas effects. The development of efficient and cost-effective electrocatalysts has been a research hotspot in the field. In this study, we designed four Co-doped single-atom catalysts (Co-Nχ@C) using carbon nanotubes as carriers, these catalysts included tri- and dicoordinated N-doped carbon nanoribbons, as well as tri- and dicoordinated N-doped graphene, respectively denoted as H3(H2)-Co/CNT and 3(2)-Co/CNT. The stable configurations of these Co-Nχ@C catalysts were optimized using the PBE+D3 method. Additionally, we explored the reaction mechanisms of these catalysts for the electrocatalytic reduction of CO2 into four C1 products, including CO, HCOOH, CH3OH and CH4, in detail. Upon comparing the limiting potentials (UL) across the Co-Nχ@C catalysts, the activity sequence for the electrocatalytic reduction of CO2 was H2-Co/CNT > 3-Co/CNT > H3-Co/CNT > 2-Co/CNT. Meanwhile, our investigation of the hydrogen evolution reaction (HER) with four catalysts elucidated the influence of acidic conditions on the electrocatalytic CO2 reduction process. Specifically, controlling the acidity of the solution was crucial when using the H3-Co/CNT and H2-Co/CNT catalysts, while the 3-Co/CNT and 2-Co/CNT catalysts were almost unaffected by the solution's acidity. We hope that our research will provide a theoretical foundation for designing more effective CO2 reduction electrocatalysts.

Arthroscopic Fixation of Bony Bankart Lesion Using Inverted All-Suture Anchor Through Bone Tunnel.

A bony Bankart lesion is a condition where the labroligamentous complex is detached from the anterior glenoid rim, often accompanied by a fracture. It is a common occurrence found in up to 70% of traumatic shoulder dislocations. Arthroscopic surgery has become the mainstream approach for treating this condition. However, the commonly used techniques, such as labrum alone, transosseous, and double-row, can encounter difficulties passing sutures and may cause damage to the surrounding tissues, especially when dealing with large bony fragments. In this technical note, we describe our preferred technique for fixing bony Bankart lesions, which involves fixing the bony Bankart fragment through the bone tunnel using an all-suture anchor. The surgery is performed with the patient in the lateral decubitus position. Our technique offers a reliable and effective approach to treat bony Bankart lesions while minimizing the risks of complications associated with conventional techniques.

GGPPS Negatively Regulates the Formation of Neutrophil Extracellular Traps in Lipopolysaccharide-Induced Acute Lung Injury.

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are life-threatening diseases. Neutrophil extracellular traps (NETs) play a key role in lung damage. Geranylgeranyl diphosphate synthase (GGPPS) is associated with the development of inflammatory diseases. We aimed to explore the role of GGPPS in NETs formation in ARDS/ALI. First, lung pathological changes in lipopolysaccharide (LPS)-induced ALI mice after myeloid-specific GGPPS deletion were evaluated. The level of NETs formation was analyzed by immunofluorescence, PicoGreen assay and Western blotting. Next, we determined the role of GGPPS in NETs formation and underlying mechanisms using immunofluorescence, flow cytometry, DCFH-DA, and SYTOX GREEN staining in vitro. Finally, the correlation between GGPPS expression incirculating neutrophils and dsDNA levels in plasma was evaluated. Myeloid-specific GGPPS deletion mice showed increased NETs deposition in lung tissue and aggravated histopathological damage of lung tissue. In vitro, GGPPS deficiency in neutrophils resulted in increased NETs formation by Phorbol-12-myristate-13-acetate (PMA), which was reversed by Geranylgeranyl diphosphate (GGPP). In addition, inhibitors blocking protein kinase C (PKC) and NADPH-oxidase (NOX) decreased NETs formation induced by GGPPS deletion. Importantly, GGPPS expression in circulating neutrophils was decreased in ARDS patients compared with the healthy control, and the level of dsDNA in plasma of ARDS patients was negatively correlated with the GGPPS expression. Taken together, GGPPS deficiency in neutrophils aggravates LPS-induced lung injury by promoting NETs formation via PKC/NOX signaling. Thus, neutrophil GGPPS could be a key therapeutic target for ARDS.

Ultrastable piezoelectric biomaterial nanofibers and fabrics as an implantable and conformal electromechanical sensor patch.

Poly(l-lactic acid) (PLLA) is a widely used U.S. Food and Drug Administration-approved implantable biomaterial that also possesses strong piezoelectricity. However, the intrinsically low stability of its high-energy piezoelectric ß phase and random domain orientations associated with current synthesis approaches remain a critical roadblock to practical applications. Here, we report an interfacial anchoring strategy for fabricating core/shell PLLA/glycine (Gly) nanofibers (NFs) by electrospinning, which show a high ratio of piezoelectric ß phase and excellent orientation alignment. The self-assembled core/shell structure offers strong intermolecular interactions between the -OH groups on Gly and C=O groups on PLLA, which promotes the crystallization of oriented PLLA polymer chains and stabilizes the ß phase structure. As-received core/shell NFs exhibit substantially enhanced piezoelectric performance and excellent stability. An all NF-based nonwoven fabric is fabricated and assembled as a flexible nanogenerator. The device offers excellent conformality to heavily wrinkled surfaces and thus can precisely detect complex physiological motions often found from biological organs.

Synergistic effects of oxygen vacancies and mesoporous structures in amorphous C@TiO2 for photocatalytic CO2 reduction.

In this study, the theoretical calculations proves that the combination of oxygen vacancy and amorphous carbon films in TiO2 (VO-CT) can effectively reduce the energy bandgap and work function. The minimum Gibbs free energies required for the CO2RR reaction of VO-CT are 0.20 eV, which is lower than pure TiO2. The amorphous c@TiO2 nanomaterials with oxygen vacancy and mesoporous structures (VO-MCT) are prepared with the P123 surfactant as the template and oxalic acid as an inducer. The electron paramagnetic resonance indicates the presence of abundant oxygen vacancy defects in the samples. UV-vis spectra indicate that the mesoporous structure enhances light absorption capacity. The photocatalytic CO2 reduction tests show that the highest conversion rates for CH4 and CO of VO-MCT are 14 µmol g-1 h-1 and 10.66 µmol g-1 h-1, respectively. The electron consumption rate of VO-MCT is 12.43 times higher than that of commercial TiO2 (P200).

Estimating lead-attributable mortality burden by socioeconomic status in the USA.

BACKGROUND: This study aimed to estimate population-level and state-level lead-attributable mortality burdens stratified by socioeconomic status (SES) class in the USA. METHODS: Based on the National Health and Nutrition Examination Survey (NHANES), we constructed individual-level SES scores from income, employment, education and insurance data. We assessed the association between the blood lead levels (BLL) and all-cause mortality by Cox regression in the NHANES cohort (n = 31 311, 4467 deaths). With estimated hazard ratios (HR) and prevalences of medium (2-5 µg/dL) and high (≥ 5 µg/dL) BLL, we computed SES-stratified population-attributable fractions (PAFs) of all-cause mortality from lead exposure across 1999-2019. We additionally conducted a systematic review to estimate the lead-attributable mortality burden at state-level. RESULTS: The HR for every 2-fold increase in the BLL decreased from 1.23 (1.10-1.38) for the lowest SES class to 1.05 (0.90-1.23) for the highest SES class. Across all SES quintiles, medium BLL exhibited a greater mortality burden. Individuals with lower SES had higher lead-attributable burdens, and such disparities haver persisted over the past two decades. In 2017-19, annually 67 000 (32 000-112 000) deaths in the USA were attributable to lead exposure, with 18 000 (2000-41 000) of these deaths occurring in the lowest SES class. Substantial disparities in the state-level mortality burden attributable to lead exposure were also highlighted. CONCLUSIONS: These findings suggested that disparities in lead-attributable mortality burden persisted within US adults, due to heterogeneities in the effect sizes of lead exposure as well as in the BLL among different SES classes.

Safety, tolerability, pharmacokinetics, and pharmacodynamics of a soluble guanylate cyclase stimulator, HEC95468, in healthy volunteers: a randomized, double-blinded, placebo-controlled phase 1 trial.

Heart failure is the most costly cardiovascular disorder. New treatments are urgently needed. This study aims to evaluate the safety, pharmacokinetics, and pharmacodynamic profile of HEC95468, a soluble guanylate cyclase (sGC) stimulator, in healthy volunteers. Sixty-two, eighteen, and forty-eight participants were enrolled in the single ascending dose (SAD) study, the food effect (FE) study, and the multiple ascending dose (MAD) study, respectively. The study conforms to good clinical practice and the Declaration of Helsinki. Overall, HEC95468 was safe and tolerable; a higher proportion of HEC95468-treated participants reported mild headaches, dizziness, decreased blood pressure, increased heart rate, and gastrointestinal-related treatment-emergent adverse events (TEAEs), similar to the sGC stimulators riociguat and vericiguat. In terms of pharmacokinetic parameters, the maximum observed plasma concentration (Cmax) and the area under the concentration-time curve (AUC0-t) were dose-proportional over the dose range. Moderate accumulation was observed after multiple administrations of HEC95468. Systolic blood pressure (SBP) and diastolic blood pressure decreased, while 3',5'-cyclic guanosine monophosphate (cGMP) concentration in plasma increased and heart rate was induced. Vasoactive hormones (renin, angiotensin II, and norepinephrine) in plasma were compensatorily elevated after oral administration. These data supported further clinical trials of HEC95468 in the treatment of heart failure and pulmonary arterial hypertension. Systematic Review Registration: http://www.chinadrugtrials.org.cn, identifier CTR20210064.

Mechano-inhibition of endocytosis sensitizes cancer cells to Fas-induced Apoptosis.

The transmembrane death receptor Fas transduces apoptotic signals upon binding its ligand, FasL. Although Fas is highly expressed in cancer cells, insufficient cell surface Fas expression desensitizes cancer cells to Fas-induced apoptosis. Here, we show that the increase in Fas microaggregate formation on the plasma membrane in response to the inhibition of endocytosis sensitizes cancer cells to Fas-induced apoptosis. We used a clinically accessible Rho-kinase inhibitor, fasudil, that reduces endocytosis dynamics by increasing plasma membrane tension. In combination with exogenous soluble FasL (sFasL), fasudil promoted cancer cell apoptosis, but this collaborative effect was substantially weaker in nonmalignant cells. The combination of sFasL and fasudil prevented glioblastoma cell growth in embryonic stem cell-derived brain organoids and induced tumor regression in a xenograft mouse model. Our results demonstrate that sFasL has strong potential for apoptosis-directed cancer therapy when Fas microaggregate formation is augmented by mechano-inhibition of endocytosis.

A novel mechanism behind irreversible development of cartilage degradation driven articular cartilage defects revealed by rat model: The chain reaction initiated by extracellular vesicles delivered LOC102546541.

BACKGROUND: Articular cartilage defects (ACD) are injuries with a diameter greater than 3 mm, resulting from wear and tear on joints. When the diameter of the defect exceeds 6 mm, it can further damage the surrounding joint cartilage, causing osteoarthritis (OA). Try to explain why OA is an irreversible disease, we hypothesize that damaged articular chondrocytes (DAC) may have reduced capacities to repair cartilage because its extracellular vesicle (EVs) that might directly contribute to OA formation. METHODS: In this study, DAC-EVs and AC-EVs were isolated using ultracentrifugation. Next-generation sequencing was employed to screen for a pathogenic long non-coding RNA (lncRNA). After verifying its function in vitro, the corresponding small interfering RNA (siRNA) was constructed and loaded into extracellular vesicles, which were then injected into the knee joint cavities of rats. RESULTS: The results revealed that DAC-EVs packaged lncRNA LOC102546541 acts as a competitive endogenous RNA (ceRNA) of MMP13, down-regulating miR-632. Consequently, the function of MMP13 in degrading the extracellular matrix is enhanced, promoting the development of osteoarthritis. CONCLUSIONS: This study uncovered a novel mode of OA pathogenesis using rat models, which DAC deliver pathogenic LOC102546541 packaged EVs to normal articular chondrocytes, amplifying the degradation of the extracellular matrix. Nonetheless, the functions of highly homologous human gene of LOC102546541 need to be verified in the future.

Spatial patterns and climatic drivers of phylogenetic structure of regional liverwort assemblages in China.

BACKGROUND AND AIMS: Latitudinal diversity gradients have been intimately linked to the tropical niche conservatism hypothesis, which posits that there has been a strong filter due to the challenges faced by ancestral tropical lineages to adapt to low temperatures and colonize extra-tropical regions. In liverworts, species richness is higher towards the tropics, but the centres of diversity of the basal lineages are distributed across extra-tropical regions, pointing to the colonization of tropical regions by phylogenetically clustered assemblages of species of temperate origin. Here, we test this hypothesis through analyses of the relationship between macroclimatic variation and phylogenetic diversity in Chinese liverworts. METHODS: Phylogenetic diversity metrics and their standardized effect sizes for liverworts in each of the 28 regional floras at the province level in China were related to latitude and six climate variables using regression analysis. We conducted variation partitioning analyses to determine the relative importance of each group of climatic variables. KEY RESULTS: We find that the number of species decreases with latitude, whereas phylogenetic diversity shows the reverse pattern, and that phylogenetic diversity is more strongly correlated with temperature-related variables compared with precipitation-related variables. CONCLUSIONS: We interpret the opposite patterns observed in phylogenetic diversity and species richness in terms of a more recent origin of tropical diversity coupled with higher extinctions in temperate regions.

Global patterns and ecological drivers of taxonomic and phylogenetic endemism in angiosperm genera.

Endemism of lineages lies at the core of understanding variation in community composition among geographic regions because it reflects how speciation, extinction, and dispersal have influenced current distributions. Here, we investigated geographic patterns and ecological drivers of taxonomic and phylogenetic endemism of angiosperm genera across the world. We identify centers of paleo-endemism and neo-endemism of angiosperm genera, and show that they are mostly located in the Southern Hemisphere in tropical and subtropical regions, particularly in Asia and Australia. Different categories of phylogenetic endemism centers can be differentiated using current climate conditions. Current climate, historical climate change, and geographic variables together explained ∼80% of global variation in taxonomic and phylogenetic endemism, while 42-46%, 1%, and 15% were independently explained by these three types of variables, respectively. Thus our findings show that past climate change, current climate, and geography act together in shaping endemism, which are consistent with the findings of previous studies that higher temperature and topographic heterogeneity promote endemism. Our study showed that many centers of phylogenetic endemism of angiosperms, including regions in Amazonia, Venezuela, and west-central tropical Africa that have not previously been identified as biodiversity hotspots, are missed by taxon-based measures of endemism, indicating the importance of including evolutionary history in biodiversity assessment.

Long-term efficacy, safety and biocompatibility of a novel sirolimus eluting iron bioresorbable scaffold in a porcine model.

Iron is considered as an attractive alternative material for bioresorbable scaffolds (BRS). The sirolimus eluting iron bioresorbable scaffold (IBS), developed by Biotyx Medical (Shenzhen, China), is the only iron-based BRS with an ultrathin-wall design. The study aims to investigate the long-term efficacy, safety, biocompatibility, and lumen changes during the biodegradation process of the IBS in a porcine model. A total of 90 IBSs and 70 cobalt-chromium everolimus eluting stents (EES) were randomly implanted into nonatherosclerotic coronary artery of healthy mini swine. The multimodality assessments including coronary angiography, optical coherence tomography, micro-computed tomography, magnetic resonance imaging, real-time polymerase chain reaction (PCR), and histopathological evaluations, were performed at different time points. There was no statistical difference in area stenosis between IBS group and EES group at 6 months, 1year, 2 years and 5 years. Although the scaffolded vessels narrowed at 9 months, expansive remodeling with increased mean lumen area was found at 3 and 5 years. The IBS struts remained intact at 6 months, and the corrosion was detectable at 9 months. At 5 years, the iron struts were completely degraded and absorbed in situ, without in-scaffold restenosis or thrombosis, lumen collapse, aneurysm formation, and chronic inflammation. No local or systemic toxicity and abnormal histopathologic manifestation were found in all experiments. Results from real-time PCR indicated that no sign of iron overload was reported in scaffolded segments. Therefore, the IBS shows comparable efficacy, safety, and biocompatibility with EES, and late lumen enlargement is considered as a unique feature in the IBS-implanted vessels.

Evolutionary history shapes variation of wood density of tree species across the world.

The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density, but this has largely not been tested. Using a comprehensive global dataset including 27,297 measurements of wood density from 2621 tree species worldwide, we test the hypothesis that the legacy of evolutionary history plays an important role in driving the variation of wood density among tree species. We assessed phylogenetic signal in different taxonomic (e.g., angiosperms and gymnosperms) and ecological (e.g., tropical, temperate, and boreal) groups of tree species, explored the biogeographical and phylogenetic patterns of wood density, and quantified the relative importance of current environmental factors (e.g., climatic and soil variables) and evolutionary history (i.e., phylogenetic relatedness among species and lineages) in driving global wood density variation. We found that wood density displayed a significant phylogenetic signal. Wood density differed among different biomes and climatic zones, with higher mean values of wood density in relatively drier regions (highest in subtropical desert). Our study revealed that at a global scale, for angiosperms and gymnosperms combined, phylogeny and species (representing the variance explained by taxonomy and not direct explained by long-term evolution process) explained 84.3% and 7.7% of total wood density variation, respectively, whereas current environment explained 2.7% of total wood density variation when phylogeny and species were taken into account. When angiosperms and gymnosperms were considered separately, the three proportions of explained variation are, respectively, 84.2%, 7.5% and 6.7% for angiosperms, and 45.7%, 21.3% and 18.6% for gymnosperms. Our study shows that evolutionary history outpaced current environmental factors in shaping global variation in wood density.

Interstitial Fluid Shear Stress Induces the Synthetic Phenotype Switching of VSMCs to Release Pro-calcified Extracellular Vesicles via EGFR-MAPK-KLF5 Pathway.

Phenotypic switching (from contractile to synthetic) of vascular smooth muscle cells (VSMCs) is essential in the progression of atherosclerosis. The damaged endothelium in the atherosclerotic artery exposes VSMCs to increased interstitial fluid shear stress (IFSS). However, the precise mechanisms by which increased IFSS influences VSMCs phenotypic switching are unrevealed. Here, we employed advanced numerical simulations to calculate IFSS values accurately based on parameters acquired from patient samples. We then carefully investigated the phenotypic switching and extracellular vesicles (EVs) secretion of VSMCs under various IFSS conditions. By employing a comprehensive set of approaches, we found that VSMCs exhibited synthetic phenotype upon atherosclerotic IFSS. This synthetic phenotype is the upstream regulator for the enhanced secretion of pro-calcified EVs. Mechanistically, as a mechanotransducer, the epidermal growth factor receptor (EGFR) initiates the flow-based mechanical cues to MAPK signaling pathway, facilitating the nuclear accumulation of the transcription factor krüppel-like factor 5 (KLF5). Furthermore, pharmacological inhibiting either EGFR or MAPK signaling pathway blocks the nuclear accumulation of KLF5 and finally results in the maintenance of contractile VSMCs even under increased IFSS stimulation. Collectively, targeting this signaling pathway holds potential as a novel therapeutic strategy to inhibit VSMCs phenotypic switching and mitigate the progression of atherosclerosis.

Patient with suspected co-infection of hemorrhagic fever with renal syndrome and malaria: a case report.

Background: Hemorrhagic fever with renal syndrome (HFRS) is a natural epidemic disease that can be caused by the Hantaan virus (HTNV). Malaria is caused by plasmodium and can be transmitted by a mosquito bite. The similar manifestations shared by these disorders pose a challenge for clinicians in differential diagnosis, in particular, coupled with a false-positive serological test. Case presentation: A 46-year-old man was admitted for fever and chills for over 10 days and was suspected of being co-infected with HFRS and malaria due to a history of travel to malaria-endemic areas and a positive HTNV-immunoglobulin M (IgM) test. Although leukocytosis, thrombocytopenia, renal injury, lymphocytosis, overexpression of interleukin-6, and procalcitonin were observed during the hospitalization, the hypotensive, oliguria, and polyuria phases of the HFRS course were not observed. Instead, typical symptoms of malaria were found, including a progressive decrease in erythrocytes and hemoglobin levels with signs of anemia. Furthermore, because the patient had no history of exposure to HFRS endemic areas, exposure to an HTNV-infected rodent, or a positive HTNV-IgG test, and false serological tests of IgM can be caused by various factors, the HFRS coinfection with malaria was ruled out. Conclusion: Misdiagnosis can be easily induced by a false serological test, in particular the IgM test which can be influenced by various factors. A combination of health history, epidemiology, physical examination, precise application of specific examinations involving tests of conventional laboratory parameters as well as well-accepted methods such as the immunochromatographic (ICG) test, real-time reverse transcription-polymerase chain reaction (PCR), and Western blot (WB), and acquaintance with disorders with similar manifestations will contribute to the precise diagnosis in clinical treatment.

Oxygen vacancy enhanced photocatalytic activity of Cu2O/TiO2 heterojunction.

In this study, a method was developed to create oxygen vacancies in Cu2O/TiO2 heterojunctions. By varying the amounts of ethylenediaminetetraacetic acid (EDTA), sodium citrate, and copper acetate, Cu2O/TiO2 with different Cu ratios were synthesized. Tests on CO2 photocatalytic reduction revealed that Cu2O/TiO2's performance is influenced by Cu content. The ideal Cu mass fraction in Cu2O/TiO2, determined by inductively coupled plasma (ICP), is between 0.075% and 0.55%, with the highest CO yield being 10.22 µmol g-1 h-1, significantly surpassing pure TiO2. High-resolution transmission electron microscopy and electron paramagnetic resonance studies showed optimal oxygen vacancy in the most effective heterojunction. Density functional theory (DFT) calculations indicated a 0.088 eV lower energy barrier for ∗CO2 to ∗COOH conversion in Cu2O/TiO2 with oxygen vacancy compared to TiO2, suggesting that oxygen vacancies enhance photocatalytic activity.

The rat as a novel model for chronic rotator cuff injuries.

Chronic rotator cuff injuries (CRCIs) still present a great challenge for orthopaedics surgeons. Many new therapeutic strategies are developed to facilitate repair and improve the healing process. However, there is no reliable animal model for chronic rotator cuff injury research. To present a new valuable rat model for future chronic rotator cuff injuries (CRCIs) repair studies, and describe the changes of CRCIs on the perspectives of histology, behavior and MRI. Sixty male Wistar rats were enrolled and underwent surgery of the left shoulder joint for persistent subacromial impingement. They were randomly divided into experimental group (n = 30, a 3D printed PEEK implant shuttled into the lower surface of the acromion) and sham operation group (n = 30, insert the same implant, but remove it immediately). Analyses of histology, behavior, MRI and inflammatory pain-related genes expression profiles were performed to evaluate the changes of CRCIs. After 2-weeks running, the rats in the experimental group exhibited compensatory gait patterns to protect the injured forelimb from loading after 2-weeks running. After 8-weeks running, the rats in the experimental group showed obvious CRCIs pathological changes: (1) acromion bone hyperplasia and thickening of the cortical bone; (2) supraspinatus muscle tendon of the humeral head: the bursal-side tendon was torn and layered with disordered structure, forming obvious gaps; the humeral-side tendon is partially broken, and has a neatly arranged collagen. Partial fat infiltration is found. The coronal T2-weighted images showed that abnormal tendon-to-bone junctions of the supraspinatus tendon. The signal intensity and continuity were destroyed with contracted tendon. At the nighttime, compared with the sham operation group, the expression level of IL-1ß and COX-2 increased significantly (P = 0063, 0.0005) in the experimental group. The expression of COX-2 in experimental group is up-regulated about 1.5 times than that of daytime (P = 0.0011), but the expression of IL-1ß, TNF-a, and NGF are all down-regulated (P = 0.0146, 0.0232, 0.0161). This novel rat model of chronic rotator cuff injuries has the similar characteristics with that of human shoulders. And it supplies a cost-effective, reliable animal model for advanced tissue engineered strategies and future therapeutic strategies.