BACKGROUND:Eucommia ulmoides has a certain osteogenic effect,which can promote the proliferation and differentiation of osteoblasts.However,it is unclear whether Eucommia ulmoides has effects on alveolar bone formation and Wnt/β-Catenin signaling pathway. OBJECTIVE:To investigate the mechanism by which Eucommia ulmoides promotes alveolar bone formation in ovariectomized rats based on the Wnt/β-Catenin signaling pathway. METHODS:Sixty female Sprague-Dawley rats were selected and randomly divided into five groups:blank control group,sham-operation group,model group,low-dose group Eucommia ulmoides group,and high-dose Eucommia ulmoides group,with twelve rats in each group.Osteoporosis animal models were constructed by bilateral oophorectomy in the model group and the low-dose and high-dose Eucommia ulmoides groups.The sham-operation group underwent the same method to remove adipose tissue of equal mass around the bilateral ovaries.Three months after surgery,the low-and high-dose Eucommia ulmoides groups were given 2.1 g/kg/d and 4.2 g/kg/d Eucommia ulmoides by gavage,respectively.The sham-operation group and model group were given the same amount of physiological saline by gavage.After 12 weeks of drug intervention,the changes in alveolar bone mass of rats in each group were observed through Micro-CT;hematoxylin-eosin staining was used to observe the pathological structural changes of alveolar bone in rats;enzyme linked immunosorbent assay was used to detect the expression levels of alkaline phosphatase and osteocalcin in the serum of rats;western blot was used to detect the expression levels of β-Catenin and Frizzled9 receptor proteins in the alveolar bone of rats;and real-time fluorescence quantitative PCR was used to detect the expression of osteocalcin,Runt-related transcription factor 2(Runx2),alkaline phosphatase,β-catenin,and frizzled9 mRNAs in alveolar bone tissues of rats. RESULTS AND CONCLUSION:Compared with the blank control group,bone volume fraction,trabecular number,trabecular thickness,and bone mineral density were reduced in the model group(P＜0.05),and trabecular separation was elevated(P＜0.05).Pathological observation showed that the arrangement of trabeculae was disordered and irregular,the trabeculae were thinned or broken,and the marrow cavity was enlarged in the model group,with a significant reduction in bone volume;the level of alkaline phosphatase in the serum was increased(P＜0.05),and the level of osteocalcin was decreased(P＜0.05);mRNA expression of alkaline phosphatase,osteocalcin,Runx2,β-catenin,and frizzled9 were decreased(P＜0.05);protein expression of β-Catenin and Frizzled9 was decreased(P＜0.05).Compared with the model group,the low-and high-dose Eucommia ulmoides groups showed an increase in bone volume fraction,trabecular number,trabecular thickness,and bone mineral density(P＜0.05)and a decrease in trabecular separation(P＜0.05).In the low-and high-dose Eucommia ulmoides groups,bone trabeculae were slightly aligned and thickened,with a significant increase in bone mass.Compared with the model group,the serum level of alkaline phosphatase was reduced(P＜0.05)and the serum level of osteocalcin was elevated(P＜0.05)in the low-and high-dose Eucommia ulmoides groups.Compared with the model group,the mRNA expression of alkaline phosphatase,osteocalcin,Runx2,β-catenin,and frizzled9 were increased in the low-and high-dose Eucommia ulmoides groups(P＜0.05).Compared with the model group,the protein expression of Frizzled9 was increased in the low-dose Eucommia ulmoides group(P＜0.05),while the protein expression of β-Catenin and Frizzled9 was increased in the high-dose Eucommia ulmoides group(P＜0.05).Compared with the low-dose Eucommia ulmoides group,the high-dose Eucommia ulmoides group had a more significant improvement in the above indexes.To conclude,Eucommia ulmoides can effectively promote the alveolar bone formation,and its mechanism of action might be related to the activation of the Wnt/β-catenin signaling pathway.

In the process of maintaining the steady state of bone tissue, the transcription network and signal pathway of the body play a vital role. These complex regulatory mechanisms need precise coordination to ensure the balance between bone formation and bone absorption. Once this balance is broken, it may lead to pathological changes of bone and cartilage, and then lead to various bone diseases. Therefore, it is of great significance to understand these regulatory mechanisms for the prevention and treatment of bone diseases. In recent years, with the deepening of research, more and more lncRNA has been found to be closely related to bone health. Among them, nuclear paraspeckle assembly transcript 1 (NEAT1), as an extremely abundant RNA molecule in mammalian nuclei, has attracted extensive attention. NEAT1 is mainly transcribed from a specific site in human chromosome 11 by RNA polymerase II (RNaseP), which can form two different subtypes NEAT1_1 and NEAT1_2. These two subtypes are different in intracellular distribution and function, but they participate in many biological processes together. Studies have shown that NEAT1 plays a specific role in the process of cell growth and stress response. For example, it can regulate the development of osteoblasts (OB), osteoclasts (OC) and chondrocytes by balancing the differentiation of bone marrow mesenchymal stem cells (BMSCs), thus maintaining the steady state of bone metabolism. This discovery reveals the important role of NEAT1 in bone development and remodeling. In addition, NEAT1 is closely related to a variety of bone diseases. In patients with bone diseases such as osteoporosis (OP), osteoarthritis (OA) and osteosarcoma (OS), the expression level of NEAT1 is different. These differential expressions may be closely related to the pathogenesis and progression of bone diseases. By regulating the level of NEAT1, it can affect a variety of signal transduction pathways, and then affect the development of bone diseases. For example, some studies show that by regulating the expression level of NEAT1, the activity of osteoclasts can be inhibited, and the proliferation and differentiation of osteoblasts can be promoted, thus improving the symptoms of osteoporosis. It is worth noting that NEAT1 can also be used as a key sensor for the prevention and treatment of bone diseases. When exercising or receiving some natural products, the expression level of NEAT1 will change, thus reflecting the response of bones to external stimuli. This feature makes NEAT1 an important target for studying the prevention and treatment strategies of bone diseases. However, although the role of NEAT1 in bone biology and bone diseases has been initially recognized, its specific mechanism and regulatory relationship are still controversial. For example, the expression level, mode of action and interaction with other molecules of NEAT1 in different bone diseases still need further in-depth study. This paper reviews the role of NEAT1 in maintaining bone and cartilage metabolism, and discusses its expression and function in various bone diseases. By combing the existing research results and controversial points, this paper aims to provide new perspectives and ideas for the prevention and treatment of bone diseases, and provide useful reference and enlightenment for future research.

Objective To investigate the clinical characteristics,treatment methods,and prognosis of a-cute leukemia patients with extramedullary infiltration.Methods The clinical characteristics and treatment methods of 47 acute leukemia patients with extramedullary infiltration admitted to the Affiliated Hospital of Guizhou Medical University from April 2014 to April 2023 were retrospectively analyzed.Subgroup analysis was performed according to whether there was extramedullary infiltration before transplantation,and whether there was isolated extramedullary recurrence after transplantation.Based on this analysis,the patients were di-vided into the pre-transplantation radiotherapy group and pre-transplantation non-radiotherapy group,the post-transplantation radiotherapy group and post-transplantation non-radiotherapy group.According to the treatment methods of central nervous system leukemia(CNSL),the patients were divided into the intrathecal injection group(n=12)and combination of intrathecal injection and radiotherapy group(n=13).The local remission situation,survival duration,and toxic and side effects of radiotherapy and chemotherapy were com-pared.Results For acute leukemia patients with extramedullary infiltration,the overall survival time(OS)in the radiotherapy group was better than that in the non-radiotherapy group(median OS:706 d vs.151 d,P=0.015).Subgroup analysis showed that the OS of the pre-transplantation radiotherapy group was better than that of the pre-transplantation non-radiotherapy group(median OS:592 d vs.386 d,P=0.035).For CNSL,the combination of intrathecal injection and radiotherapy group had a better OS than the intrathecal injection group(median OS:547 d vs.388 d,P=0.045).The event-free survival time(EFS)of the radiotherapy group was better than that of the non-radiotherapy group(median EFS:175 d vs.50 d,P=0.005).The COX pro-portional-hazards model showed that treatment with or without radiotherapy had a significant impact on the OS of acute leukemia patients with extramedullary infiltration.The risk of death in the pre-transplantation non-radiotherapy group was 2.231 times higher than that in the pre-transplantation radiotherapy group(HR=3.231,95％CI:1.021-10.227,P=0.046).Compared with the non-radiotherapy group,the radiother-apy group had a higher local remission and a lower risk of haematological toxicity,infection,and haemorrhage.Conclusion Radiotherapy can rapidly alleviate the local symptoms of acute leukemia complicated with extr-amedullary infiltration,prolong the survival time of these patients,and reduce the risk of hematologic toxicity,infection,and haemorrhage.

Objective To screen the optimal regimen of Chinese medicine combined with hormones for the treatment of premature ovarian failure(POF)using network meta-analysis and to provide an evidence-based basis for the clinical treatment of POF.Methods The randomized controlled trials(RCTs)of Chinese medicine combined with hormones in the treatment of POF were retrieved from thhe domestic and oversea databases of CNKI,VIP,Wanfang,CBM,PubMed,Cochrane,Embase,and Web of Science.The quality of the literature was assessed using the tools for analysis of bias recommended by Cochrane Reviewer's Handbook and by Jadad scale scores.Rstudio and StataSE 15.1 statistical software were used to perform network meta-analysis and graphical presentation of the data.Results A total of 50 RCTs were included,covering 8 intervention methods.The overall risk of bias of the included studies was low,but the quality of the literature was generally low.The results of network meta-analysis showed that,in terms of the effective rate,the intervetion of 7 various Chinese medicines combined with hormone was superior to the conventional treatment(hormone replacement therapy,HRT)in the control group,and Nuangong Qiwei Powder+HRT was superior to the remaining 6 kinds of Chinese medicines combined with HRT;with reference to the values of the surface under the cumulative ranking curve(SUCRA),the efficiencies of the effective rate of the 8 intervention methods in descending order were Nuangong Qiwei Powder+ HRT(SUCRA=81.2),Zishen Yutai Pills + HRT(SUCRA=80.0),modified Zuogui Pills + HRT(SUCRA= 66.1),Ankun Zhongzi Pills + HRT(SUCRA=49.6),Kuntai Capsules + HRT(SUCRA=45.2),modified Erxian Decoction + HRT(SUCRA=39.5),Liuwei Dihuang Pills + HRT(SUCRA=37.4)and HRT(SUCRA=1.0).In terms of improving serum follicle-stimulating hormone(FSH)levels,modified Zuogui Pills + HRT was superior to the remaining 7 intervention methods;with reference to the values of the SUCRA,the efficiencies of the 8 intervention methods in descending order were modified Zuogui Pills + HRT(SUCRA=97.0),HRT(SUCRA= 77.9),Liuwei Dihuang Pills + HRT(SUCRA=76.6),Kuntai Capsules + HRT(SUCRA=46.5),Nuangong Qiwei Powder+HRT(SUCRA=38.9),Ankun Zhongzi Pills + HRT(SUCRA=29.9),modified Erxian Decoction + HRT(SUCRA=18.1),and Zishen Yutai Pills + HRT(SUCRA=15.1).Conclusion All kinds of Chinese medicines combined with HRT exert stronger effect on improving the primary outcome indicators than HRT alone for the treatment of POF.The intervention with Nuangong Qiwei Powder+HRT exerts the highest probability of the optimal regimen for enhancing the efficiency,and the intervention with Zuogui Pills + HRT exerts the highest probability of the optimal regimen for lowering the serum FSH level.However,due to the low quality of the included studies,more rigorously-designed,large sample-size,and high-quality randomized controlled trials need to be conducted in the future to provide conclusive evidence-based evidence.

Objective There is a Few studies explored the association between vitamin intake and meta-bolic dysfunction-associated fatty liver disease(MAFLD),while the existing results were still contradictory.This study aimed to investigate the association between dietary vitamins and all-cause mortality as well as fibrosis risk in patients with MAFLD.Methods The data were extracted from the third National Health and Nutrition Examination Surveys 1988-1994.Dietary vitamins was assessed using a 24 h diet recall,including vitamin A,vitamin B6,vitamin B12,vitamin C,vitamin D,thiamin,riboflavin,folic acid and α-tocopherol.The non-alcoholic fatty liver disease fibrosis score(NFS)<-1.455 was considered as non-advanced fibrosis,while NFS≥-1.455 was considered as advanced fibrosis.Results A total of 3844 MAFLD participants were included in this study.The median time of follow-up was 310 months.1739 participants(45.3%)were deceased during the follow-up.The intake of thiamin,riboflavin,α-tocopherol,VB6,and VB12 were significantly higher in patients with NFS-determined non-advanced fibrosis(P<0.05).After adjusting,a significantly lower risk of fibrosis was found in patients with the highest quartile(>11.5 mg/d)of α-tocopherol intake compared to the lowest intake group(P = 0.031).Compared to the lowest quartile group,the risk of mortality was reduced by 0.34 folds in the group consuming the highest quartile amount(>130 mg/d)of VC(HRs:0.66,95%CI:0.51～0.85,P = 0.001).Conclusions More α-tocopherol intake reduced fibrosis grade in MAFLD patients.VC intake may reduce all-cause mortality in patients with MAFLD.

Objective To explore the role and possible molecular mechanism of Isocitrate dehydrogenase 1(IDH1)gene in proliferation and migration of intrahepatic cholangiocarcinoma(iCCA)cell HuCCT1.Methods HuCCT1 cells with IDH1 gene knockout(HuCCT1IDH1-/-)were constructed by CRISPR/Cas9 gene editing technology.To investigate the capacities of proliferation,migration and invasion of HuCCT1WT(HuCCT1 cells with wild-type IDH1 gene)and HuCCT1IDH1-/-cells,assays of CCK-8,clone formation,scratch and transwell were performed.Western blotting was used to detect the expression levels of epithelial-mesenchymal transition(EMT)associated proteins E-cadherin,N-cadherin,Vimentin,MMP-9,Wnt3a and β-catenin in two groups of cells.The transcriptome sequencing data of HuCCT1WT and HuCCT1IDH1-/-cells were analyzed by bioinformatics methods,Western blotting was used to verify the expression of signaling pathway-related proteins.Results Compared with HuCCT1WT cells,HuCCT1IDH1-/-cells showed the number of proliferation and clone formation significantly reduced(P<0.05),the proportion of cells blocked in G2/M phase was significantly increased(P<0.01),the rate of scratch healing was significantly decreased(P<0.01),and the number of migrated cells(P<0.001)and invaded cells(P<0.05)was significantly reduced.qRT-PCR assay showed that the expression levels of IDH1,Vimentin,MMP-9 and genes related to the regulation of G2/M cycle proliferation,Cyclin A2,Cyclin B1 and CDK1 mRNA were down-regulated in HuCCT1IDH1-/-cells(P<0.05),and the expression of CDH1 mRNA encoding E-cadherin was up-regulated(P<0.01);Western blotting assay showed that the expression level of E-cadherin in HuCCT1IDH1-/-cells was significantly increased(P<0.05),and the expression level of N-cadherin,Vimentin and MMP-9 protein was significantly decreased(P<0.05)than that in HuCCT1WT cells.Data of transcriptome sequencing revealed 1476 differentially expressed genes(DEGs)between two groups of HuCCT1 cells.Go enrichment analysis showed the DEGs were significantly enriched in cell biological processes associated with inflammatory response,cell signaling and cell metabolism.Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis suggested that the DEGs may be involved in some signaling pathways such as Wnt,MAPK,Rap1,Hippo and TNF,which are closely related to the regulation of proliferation and invasion of tumor cells.Western blotting verification results showed that compared with HuCCT1WT cells,the relative expression of Wnt3a and β-catenin proteins of HuCCT1IDH1-/-cells was significantly decreased(P<0.05).Conclusions IDH1 gene may participate in the control of biological functions of HuCCT1 cells,including cell proliferation,migration,invasion and epithelial mesenchymal transition.The mechanism may be related to the activation of the Wnt/β-catenin signaling pathway.

Objective To investigate the need for and utilization of health services among six Zhiguo ethnic minority groups in Yunnan Province,aiming to provide further evidence for the improvement of healthcare.Methods Using stratified random sampling,1921 individuals from six Zhiguo ethnic minority groups,aged 15 and above,were investigated with a structured questionnaire between August and December 2022.A structured questionnaire was used to collect participants'information on health service needs and utilization.Results Am-ong the surveyed participants,the two-week prevalence rate was found to be 22.54%,while the prevalence rate of chronic diseases was 38.52%.Among the residents,the risk of two-week prevalence was higher for females(OR=1.564),individuals aged≥60 years(OR=1.727),and those who reported poorer health utility value(OR=5.277),while it was lower for residents of Keno(OR=0.470)and Lahu(OR=0.659)ethnicity,as well as those who reported higher EQ-VAS scores(OR=0.446/0.174).Meanwhile,residents aged≥45 years(OR=3.392/7.072)were at higher risk for chronic disease prevalence,while it was lower for Keno ethnicity(OR=0.409),unmarried individuals(OR=0.479),and those with higher education levels(OR=0.629/0.603),higher EQ-VAS scores(OR=0.208)P<0.05.Additionally,among the participants,the treat-ment rate for two-week illness was 14.32%,while the non-treatment rate stood at 36.49%.Furthermore,the one-year hospitalization rate was reported as 19.89%,with a corresponding rate of individuals who needed hospitalization but did not receive it being recorded at 15.86%.Among the residents,the likelihood of treatment for two-week illness was higher for females(OR=1.461)and residents aged≥45 years(OR=1.510/1.560),whereas it was lower for individuals with higher EQ-VAS scores(OR=0.445).The likelihood of hospitalization within one year was also higher for residents aged≥60 years(OR=2.029)and individuals of Nu(OR=1.599),Lisu(OR=1.688),and Keno(OR=1.968)ethnicity,whereas those with high EQ-VAS scores(OR=0.325)had a lower risk(P<0.05).Conclusion In Yunnan Province,the need for healthcare services among six Zhiguo ethnic minority groups in this study is relatively low;however,the high prevalence of chronic diseases raises concerns.The utilization of healthcare services appears to be relatively sufficient,but the utilization of outpatient services still needs to be improved.

Osteoporosis leads to an imbalance in bone remodelling, where bone resorption is greater than bone formation and osteoclast degradation increases, resulting in severe bone loss. Autophagy is a lysosomal degradation pathway that regulates the proliferation, differentiation, and apoptosis of various bone cells (including osteoblasts, osteoclasts, and osteoclasts), and is deeply involved in the bone remodelling process. In recent years, the role of autophagy in the progression of osteoporosis and related bone metabolic diseases has received more and more attention, and it has become a research hotspot in this field. Summarising the existing studies, it is found that senile osteoporosis is the result of a combination of factors. On the one hand, it is the imbalance of bone remodelling and the increase of bone resorption/bone formation ratio with ageing, which causes progressive bone loss. On the other hand, aging leads to a general decrease in the level of autophagy, a decrease in the activity of osteoblasts and osteoclasts, and an inhibition of osteogenic differentiation. The lack of oestrogen leads to the immune system being in a low activation state, and the antioxidant capacity is weakened and inflammatory response is increased, inducing autophagy-related proteins to participate in the transmission of inflammatory signals, excessive accumulation of reactive oxygen species (ROS) in the skeleton, and negatively regulating bone formation. In addition, with aging and the occurrence of related diseases, glucocorticoid treatments also mediate autophagy in bone tissue cells, contributing to the decline in bone strength. Exercise, as an effective means of combating osteoporosis, improves bone biomechanical properties and increases bone density. It has been found that exercise induces oxidative stress, energy imbalance, protein defolding and increased intracellular calcium ions in the organism, which in turn activates autophagy. In bone, exercise of different intensities activates messengers such as ROS, PI3K, and AMP. These messengers signal downstream cascades, which in turn induce autophagy to restore dynamic homeostasis in vivo. During exercise, increased production of AMP, PI3K, and ROS activate their downstream effectors, AMPK, Akt, and p38MAPK, respectively, and these molecules in turn lead to activation of the autophagy pathway. Activation of AMPK inhibits mTOR activity and phosphorylates ULK1 at different sites, inducing autophagy. AMPK and p38 up-regulate per-PGC-1α activity and activate transcription factors in the nucleus, resulting in increased autophagy and lysosomal genes. Together, they activate FoxOs, whose transcriptional activity controls cellular processes including autophagy and can act on autophagy key proteins, while FoxOs proteins are expressed in osteoblasts. Exercise also regulates the expression of mTORC1, FoxO1, and PGC-1 through the PI3K/Akt signalling pathway, which ultimately plays a role in the differentiation and proliferation of osteoblasts and regulates bone metabolism. In addition, BMPs signaling pathway and long chain non-coding RNAs also play a role in the proliferation and differentiation of osteoblasts and autophagy process under exercise stimulation. Therefore, exercise may become a new molecular regulatory mechanism to improve osteoporosis through the bone autophagy pathway, but the specific mechanism needs to be further investigated. How exercise affects bone autophagy and thus prevents and treats bone-related diseases will become a future research hotspot in the fields of biology, sports medicine and sports science, and it is believed that future studies will further reveal its mechanism and provide new theoretical basis and ideas.

ObjectiveHuman Ku70 protein mainly involves the non-homologous end joining (NHEJ) repair of double-stranded DNA breaks (DSB) through its DNA-binding properties, and it is recently reported having an RNA-binding ability. This paper is to explore whether Ku70 has RNA helicase activity and affects miRNA maturation. MethodsRNAs bound to Ku protein were analyzed by RNA immunoprecipitation sequencing (RIP-seq) and bioinfomatic anaylsis. The expression relationship between Ku protein and miRNAs was verified by Western blot (WB) and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) assays. Binding ability of Ku protein to the RNAs was tested by biolayer interferometry (BLI) assay. RNA helicase activity of Ku protein was identified with EMSA assay. The effect of Ku70 regulated miR-124 on neuronal differentiation was performed by morphology analysis, WB and immunofluorescence assays with or without Zika virus (ZIKV) infection. ResultsWe revealed that the Ku70 protein had RNA helicase activity and affected miRNA maturation. Deficiency of Ku70 led to the up-regulation of a large number of mature miRNAs, especially neuronal specific miRNAs like miR-124. The knockdown of Ku70 promoted neuronal differentiation in human neural progenitor cells (hNPCs) and SH-SY5Y cells by boosting miR-124 maturation. Importantly, ZIKV infection reduced the expression of Ku70 whereas increased expression of miR-124 in hNPCs, and led to morphologically neuronal differentiation. ConclusionOur study revealed a novel function of Ku70 as an RNA helicase and regulating miRNA maturation. The reduced expression of Ku70 with ZIKV infection increased the expression of miR-124 and led to the premature differentiation of embryonic neural progenitor cells, which might be one of the causes of microcephaly.

Objective To investigate the effects of medullary differentiation-2(MD-2)in obesity-induced myocardial injury by regulating adenosine 5'-monophosphate-activated protein kinase(AMPK)activity.Methods The obese mice model was established by feeding high-fat feed.The wild-type and MD-2 gene knockout mice were randomly divided into wild-type(WT)-control group(fed normally),WT-model group(fed with high-fat diet),knockout(KO)-control group(fed normally)and KO-model group(fed with high-fat diet)with 8 mice in each group.At week 16,creatine kinase-MB(CK-MB)and lactate dehydrogenase(LDH)were measured by reagent kits;the left ventricular ejection fraction(LVEF)and left ventricular fraction shortening(LVFS)were measured with ultrasonic apparatus;the pathological changes in myocardial tissue were observed by hematoxylin and eosin(HE)staining and Masson staining;the protein expression of phosphorylation AMPK(p-AMPK)was measured by Western blot.Results HE staining and Masson staining results revealed significant necrosis and fibrosis of the myocardial tissue in WT-model group,while the degrees of necrosis and fibrosis in KO-model group were significantly reduced.The LVEF values of the WT-control group,WT-model group,KO-control group and KO-model group were(83.98±7.58)％,(52.03±4.91)％,(76.42±3.89)％and(73.71±4.22)％,respectively;the LVFS values of each group were(53.61±8.51)％,(24.56±3.76)％,(48.14±5.00)％and(44.07±3.74)％,respectively;the CK-MB values of each group were(49.83±15.49),(83.75±11.90),(54.03±18.66)and(66.85±12.98)U·L-1,respectively;the LDH values of each group were(12.24±3.20),(27.90±6.10),(13.55±3.55)and(15.53±2.58)U·L-1,respectively;the relative expression levels of p-AMPK in each group were 221.31±88.76,46.29±10.07,148.66±32.02 and 161.49±78.11.Compared with WT-control group,the above indicators in WT-model group,compared with WT-model group,the above indicators in KO-model group,the differences were statistically significant(all P＜0.05).Conclusion MD-2 mediates high-fat feed induced myocardial injury in obese mice by inhibiting AMPK activity.