BACKGROUND:Forskolin,a diterpenoid natural compound extracted from Coleus forskohlii,has a crucial regulatory role in skeletal muscle repair.However,the regulatory role of forskolin on myogenic differentiation of C2C12 skeletal muscle cells has not been fully explored.OBJECTIVE:To explore the effects of forskolin on the differentiation of C2C12 myoblast cell line and probe into the underlying molecular mechanisms.METHODS:C2C12 cells were treated with 0,0.1,0.25,0.5,1,5,10 and 20 μmol/L forskolin during growth,and cell proliferation was detected by cell counting kit-8 and qRT-PCR.C2C12 cells were treated with 0,0.25,0.5 and 1 μmol/L forskolin during the induction of myogenic differentiation.Immunofluorescence staining and qRT-PCR were used to detect C2C12 cells differentiation.Western blot was used to detect the expression level of myogenic differentiation-related signaling pathway proteins.RESULTS AND CONCLUSION:(1)The viability of C2C12 cells was decreased and cell proliferation was inhibited after treatment with high concentrations(＞1 μmol/L)of forskolin.(2)The qRT-PCR results showed that forskolin up-regulated the expression of Myh2,Myh4,Myomaker,but down-regulated the expression of Myh7 compared with the 0 μmol/L group,when C2C12 cells were differentiated for 4 days.Immunofluorescence staining results showed that the fusion index and myotube diameter of C2C12 cells were increased after forskolin treatment,and the number of myotubes was also increased.(3)Western blot results showed that the phosphorylated extracellular signal-regulated kinase 1/2 expression was inhibited;however,the phosphorylated protein kinase B was promoted after treatment with forskolin.The protein expression level of the myogenic differentiation transcription factor Myogenin was significantly up-regulated after treatment with forskolin.The above results demonstrate that forskolin may promote myogenic differentiation of C2C12 skeletal muscle cells through the extracellular signal-regulated kinase 1/2 and protein kinase B signaling pathway.

ObjectiveTo investigate the effect and mechanism of transplantation of human umbilical cord mesenchymal stem cell （hUC-MSC） with overexpression of the Numb gene in the treatment of cholestatic liver fibrosis （CLF）. MethodsThe technique of lentiviral transfection was used to induce the overexpression of the Numb gene in hUC-MSC （hUC-MSC^Numb-OE）， and hUC-MSC transfected with empty vector （hUC-MSC^OE-EV） was used as negative control. Bile duct ligation （BDL） was performed to establish a rat model of CLF， and then the rats were randomly divided into BDL group， hUC-MSC group， hUC-MSC^OE-EV group， and hUC-MSC^Numb-OE group， while a sham-operation group was also established. The rats in the intervention groups were given a single splenic injection of the corresponding cells after BDL， and samples were collected at the end of week 4. Related indicators were measured， including serum biochemistry， liver histopathology， the content of hydroxyproline （Hyp） in the liver， hepatic stellate cell activation， ductular reaction， liver regeneration， and the expression levels of key molecules in the Numb-p53 signaling axis. A one-way analysis of variance was used for comparison of continuous data between multiple groups， and the least significant difference t-test was used for further comparison between two groups. ResultsCompared with the BDL group， the hUC-MSC group and the hUC-MSC^OE-EV group had significant reductions in the levels of serum biochemical parameters （aspartate aminotransferase， gamma-glutamyl transpeptidase， total bile acid， total bilirubin， and direct bilirubin）， liver fibrosis markers （the content of Hyp and the expression levels of alpha-smooth muscle actin， tumor necrosis factor-α， and transforming growth factor-beta 1）， and ductular reaction markers （the expression levels of CK7 and CK19） （all P <0.05）， and compared with the hUC-MSC^OE-EV group， the hUC-MSC^Numb-OE group had significantly greater improvements in the above indicators （all P <0.05）. In addition， compared with the hUC-MSC^OE-EV group， the hUC-MSC^Numb-OE group had significant improvements in the expression levels of liver regeneration-related markers （albumin and hepatocyte nuclear factor 4α） and the molecules associated with the Numb-p53 signaling axis （Numb， pNumb， Mdm2， and p53） （all P <0.05）. ConclusionOverexpression of the Numb gene can enhance the therapeutic effect of hUC-MSC on CLF， possibly by activating the Numb-PTB^L-p53-HNF4α axis， promoting the hepatic differentiation of hUC-MSCs and subsequently enhancing liver regeneration.

ObjectiveTo elucidate the mechanism by which total flavonoids of Abelmoschi Corolla （TFA） treat immunoglobulin A （IgA） nephropathy （IgAN） through serum metabolomics analysis. MethodsSPF-grade male SD rats were randomly assigned into six groups （n=10）： blank， model， low-dose TFA （TFA-L， 27 mg·kg^-1）， medium-dose TFA （TFA-M， 54 mg·kg^-1）， high-dose TFA （TFA-H， 108 mg·kg^-1）， and losartan potassium （LST， 4.5 mg·kg^-1） groups. The remaining five groups， excluding the blank group， were modeled with bovine serum albumin （BSA）， lipopolysaccharide （LPS）， and carbon tetrachloride （CCl₄）. Specifically， from weeks 1 to 10， BSA was administered via gavage every other day， and a mixture of castor oil and CCl₄ was injected subcutaneously once a week， with LPS injected into the tail vein at weeks 6 and 8. After successful modeling， each intervention group was administrated with the medication prepared with distilled water once daily by gavage for a continuous period of 4 weeks. The levels of 24-hour urinary total protein （24 h UP） and serum creatinine （SCr） were quantified by kits， and the serum IgA level was determined by enzyme-linked immunosorbent assay （ELISA）. Renal pathological changes were observed by hematoxylin-eosin （HE） staining and periodic acid-Schiff （PAS） staining. Renal IgA deposition was assessed by immunofluorescence （IF）. Endoplasmic reticulum （ER） stress was observed by transmission electron microscopy. Western blot and immunohistochemistry （IHC） were employed to detect the expression of ER stress-related factors. Non-targeted metabolomics was used to screen differential metabolites for analysis， and key metabolites arachidonic acid （AA）， prostaglandin E₂ （PGE₂）， and cyclooxygenase-2 （COX-2） were validated. ResultsCompared with the blank group， the model group showed increased 24-hour urine protein （24 h UP） and serum creatinine （SCr） levels （P<0.01）， obvious renal pathological damage， elevated serum IgA level （P<0.01）， increased renal AA and PGE₂ levels （P<0.01）， and up-regulated protein levels of COX-2， glucose-regulated protein 78 （GRP78）， phosphorylated eukaryotic initiation factor 2α （P-EIF2α）， activating transcription factor 4 （ATF4）， inositol-requiring enzyme 1α （IRE1α）， and spliced X-box binding protein 1 （XBP1s） in the renal tissue （P<0.05， P<0.01）. Compared with the model group， the intervention groups showed reductions in 24 h UP and SCr levels （P<0.05， P<0.01）， alleviated renal pathological injury， decreased serum IgA level （P<0.05， P<0.01）， and reduced renal AA and PGE₂ levels （P<0.01）. Western blot and IHC results showed that TFA reduced the levels of COX-2， GRP78， P-EIF2α， ATF4， IRE1α， and XBP1s in the renal tissue （P<0.05， P<0.01）. Metabolomics results indicated that 51 commonly differential metabolites were found among the normal， model， and TFA-M groups. TFA ameliorated IgAN by affecting metabolic pathways related to the biosynthesis of arachidonic acid and arginine through L-aspartic acid， prostaglandin 2α， leukotriene B₄， leukotriene D₄， among others. ConclusionTFA can regulate the arachidonic acid metabolism pathway， thereby modulating ER stress， reducing renal damage， and ameliorating IgA nephropathy.

BACKGROUND:Forskolin,a diterpenoid natural compound extracted from Coleus forskohlii,has a crucial regulatory role in skeletal muscle repair.However,the regulatory role of forskolin on myogenic differentiation of C2C12 skeletal muscle cells has not been fully explored.OBJECTIVE:To explore the effects of forskolin on the differentiation of C2C12 myoblast cell line and probe into the underlying molecular mechanisms.METHODS:C2C12 cells were treated with 0,0.1,0.25,0.5,1,5,10 and 20 μmol/L forskolin during growth,and cell proliferation was detected by cell counting kit-8 and qRT-PCR.C2C12 cells were treated with 0,0.25,0.5 and 1 μmol/L forskolin during the induction of myogenic differentiation.Immunofluorescence staining and qRT-PCR were used to detect C2C12 cells differentiation.Western blot was used to detect the expression level of myogenic differentiation-related signaling pathway proteins.RESULTS AND CONCLUSION:(1)The viability of C2C12 cells was decreased and cell proliferation was inhibited after treatment with high concentrations(＞1 μmol/L)of forskolin.(2)The qRT-PCR results showed that forskolin up-regulated the expression of Myh2,Myh4,Myomaker,but down-regulated the expression of Myh7 compared with the 0 μmol/L group,when C2C12 cells were differentiated for 4 days.Immunofluorescence staining results showed that the fusion index and myotube diameter of C2C12 cells were increased after forskolin treatment,and the number of myotubes was also increased.(3)Western blot results showed that the phosphorylated extracellular signal-regulated kinase 1/2 expression was inhibited;however,the phosphorylated protein kinase B was promoted after treatment with forskolin.The protein expression level of the myogenic differentiation transcription factor Myogenin was significantly up-regulated after treatment with forskolin.The above results demonstrate that forskolin may promote myogenic differentiation of C2C12 skeletal muscle cells through the extracellular signal-regulated kinase 1/2 and protein kinase B signaling pathway.

[Objective] To explore the therapeutic effects of intravenous immunoglobulin (IVIG) on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC). [Methods] C57BL/6 mice were randomly assigned to the control group, the DSS group (model) and the DSS+IVIG group (treatment). The DSS group and the DSS+IVIG group received 3% DSS in drinking water to establish the acute UC mouse model. During the experiment, the DSS+IVIG group received IVIG (1 g/kg/2d) via tail vein injection, while the DSS group received equivalent saline via tail vein injection at the same dose and frequency. The symptoms of the mice were observed, body weight changes were recorded, and the disease activity index (DAI) was calculated daily. At the end of the experiment, hematoxylin-eosin (HE) staining was used to observe the pathological changes and inflammatory cell infiltration of colon tissue; Periodic acid-Schiff (PAS) staining was used to quantify the number of goblet cells; Luminex was used to detect the levels of inflammatory-related cytokines (such as TNF-α, IL-6 and MMPs) in colon; western blot and qRT-PCR were respectively used to detect the protein expression and mRNA levels of tight junction proteins (ZO-1, Occludin, Claudin-3). [Results] DSS induced weight loss, diarrhea, bloody stool, increased DAI score, and shortened colon length in mice. Compared with DSS group, after the administration of IVIG, the DAI score was significantly reduced (P<0.001), colon length was increased (P<0.001), infiltration of inflammatory cells and pathological damage were alleviated in colonic mucosa (P<0.001), the number of goblet cells were increased (P<0.05), and the levels of inflammatory-related cytokines TNF-α, IL-6, IL-6R, MMP2, MMP3 and Chitinase3like1 were decreased (all P<0.05). Western blot and qRT - PCR results showed that IVIG significantly up-regulated the protein expression of ZO-1, Occludin and claudin-3 (all P<0.05) and the mRNA levels of ZO-1 and Occludin (all P<0.05). [Conclusion] IVIG has protective effects on colitis by inhibiting the pathological release of inflammatory-related cytokines such as TNF-α, IL-6 and MMPs and restoring the integrity of intestinal barrier.

Adenosine triphosphate(ATP),as a rich energy currency in cells,is released into the extracellular space through a variety of regulatory mechanisms.The role of extracellular ATP(eATP)and related purine and pyrimidine nucleotides as extracellu-lar signal molecules regulating immune cell function has been reported as evidence of purine signal transduction and has become the focus of attention as a therapeutic target for various diseases.Mast cells(MC)are distributed in tissues that come into contact with the external environment and are the first immune cells to respond to non-microbial environmental antigens.Although eATP is considered to be an activator of MC,the details remain to be further elucidated.This article describes the role of purine receptor signaling in MC degranulation.It expands the further understanding of the mechanism of allergic diseases,and further provides ideas for finding new targets for the treatment of allergic diseases and formulating new treatment strategies.

Objective·To observe the impact of hip synovitis on the long-term outcomes of free vascularized fibular grafting(FVFG)for osteonecrosis of femoral head(ONFH).Methods·Between October 2001 and December 2013,370 patients diagnosed with ONFH(556 hips)underwent FVFG.Preoperative synovitis was assessed using magnetic resonance imaging(MRI)and quantified with the Hip Inflammation MRI Scoring System(HIMRISS).Patients were divided into no synovitis group,moderate synovitis group,and severe synovitis group.Harris hip scores and the incidence of total hip arthroplasty were collected with an average follow-up duration of 90.5 months(range:5-215 months).Hip survival failure(defined as a Harris hip score lower than 80 at the final follow-up or the occurrence of total hip arthroplasty)was calculated.Multivariable Cox regression analysis was adopted to compare the influence of different degrees of synovial inflammation on long-term prognosis.Results·The proportion of hip survival failure was 28.0％in patients without synovitis and 28.5％in those with moderate synovitis,whereas it was significantly higher(60.4％)in patients with severe synovitis.The results of multivariable Cox regression analysis showed that severe synovitis was an independent risk factor for poor prognosis(HR 2.06,95％CI 1.21-3.53)after adjusting for age,gender,education level,marital status,ONFH type,affected side of ONFH,smoking history,baseline Harris hip score and other hip MRI-based covariates(collapse,bone marrow edema,and degeneration).Conclusion·Severe synovitis in patients with ONFH significantly increases the failure rate of hip preservation after FVFG,and the severity of synovitis should be considered in surgical decision-making.

Objective·To investigate the association of insulin resistance with left ventricular(LV)remodeling after ST-segment elevation myocardial infarction(STEMI)in patients without a history of diabetes mellitus.Methods·This study consecutively enrolled STEMI patients without a history of diabetes mellitus who underwent percutaneous coronary intervention in the Department of Cardiology of Ruijin Hospital,Shanghai Jiao Tong University School of Medicine,from January 2014 to December 2022.The patients were followed up for 6 months.Age,gender,smoking status,blood pressure,body mass index,biochemical indexes(liver function,kidney function,lipid profiles,glycemic levels and peak troponin levels,etc.)and pharmacological treatment were recorded.Homeostasis model assessment of insulin resistance(HOMA-IR)was used to evaluate insulin resistance and mean values of visit-to-visit HOMA-IR were calculated.Patients were divided into 4 groups(low-level group,low-to-medium-level group,medium-to-high-level group,and high-level group)according to the quartiles of mean HOMA-IR levels.Echocardiography was performed at baseline and during follow-up.Then the association between mean values of insulin resistance and post-infarction LV remodeling was analyzed.Results·A total of 219 patients were finally included,with an average age of(62.7±11.9)years,and male patients accounted for 85.4％(187 cases).The average follow-up time was(6.4±1.8)months.During follow-up,the average number of HOMA-IR measurements was(4.32±2.18),and the mean value of visit-to-visit HOMA-IR was 2.41(1.58,3.98),which was higher than normal range.The results showed that post-infarction LV end-diastolic diameter(P=0.027)and LV end-diastolic volume index(P=0.013)generally showed a trend for dilation with increasing mean HOMA-IR levels.Pearson correlation analysis revealed the mean values of visit-to-visit HOMA-IR were positively correlated to changes in LV dimensions(△ LV end-diastolic volume index:r=0.20,P=0.003;△ LV end-diastolic diameter:r=0.21,P=0.002).Multivariate regression analysis demonstrated that higher HOMA-IR was independently associated with greater LV dilation after STEMI,even after adjusting for age,gender,traditional risk factors(history of hypertension,body mass index,smoking status,renal function and lipid profiles),pharmacological treatment,baseline LV ejection fraction and peak troponin levels.Compared with patients with the lowest quartile of HOMA-IR,those with the highest HOMA-IR quartile exhibited a 7.727 mL/m2 increase in LV end-diastolic volume index(P＜0.001).Conclusion·This study reveals that insulin resistance is prevalent in STEMI patients without a history of diabetes mellitus.Insulin resistance is an independent predictor of adverse LV remodeling in this population.

Postoperative infection of internal fixation of closed fractures the lower limbs in adults represents a devastating complication, characterized by diagnostic challenges, prolonged treatment duration and high disability rates. Current management of these infections faces multiple challenges, such as difficulties in early accurate diagnosis, and various controversies about the treatment plan, leading to poor overall diagnosis and treatment results. To address these issues, based on evidence-based medicine and principles with emphasis on scientific rigor, clinical applicability and innovation, the Trauma Branch of the Chinese Medical Association, Orthopedic Branch of the Chinese Medical Doctor Association, Orthopedics Branch of the Chinese Medical Association, and Trauma Orthopedics and Polytrauma Group of the Resuscitation and Emergency Committee of the Chinese Medical Doctor Association have collaboratively organized a panel of relevant experts to develop the Guideline for diagnosis and treatment of infection after internal fixation of closed lower limb fractures in adults ( version 2025). The guideline proposed 10 recommendations, aiming to provide a foundation for standardized diagnosis and treatment of postoperative infection in adults with closed lower limb fractures.

Paraplegia caused by spinal cord injury is a serious neurological complication, for which surgery is currently the main treatment method. Due to different surgical approaches, patients are usually expected to maintain a passive prone position for a long time or switch between the supine and prone positions. Affected by multiple factors such as neurogenic sensory disorders, pathological changes in muscle tone and operative duration, the risk of intraoperative acquired pressure injury (IAPI) is significantly increased. Current clinical prevention strategies for IAPI in these patients predominantly focus on localized pressure relief during positioning, lacking systematic, standardized comprehensive prevention protocols or evidence-based guidelines. To address it, Department of Nursing, Orthopedics Branch, China International Exchange and Promotive Association for Medical and Health Care, Spinal Trauma Professional Committee, Orthopedics Branch, Chinese Medical Doctor Association, Nursing Group of Spine and Spinal Cord Professional Committee of Chinese Association of Rehabilitation Medicine organized experts in relevant fields to formulate Guideline for the prevention of intraoperative acquired pressure injury in paraplegic patients with spinal cord injury ( version 2025), based on evidence-based medical evidence and latest research results and clinical practice at home and abroad. Eleven recommendations were put forward from the aspects of preoperative risk assessment, intraoperative prevention strategies, postoperative handover and monitoring, and supportive mechanisms for IAPI prevention, aiming to standardize the prevention measures and management strategies of IAPI in paraplegic patients with spinal cord injury and accelerate the recovery of patients and improve the therapeutic effect.