Cell adhesion molecule L1 like plays a role in the pathogenesis of idiopathic hypogonadotropic hypogonadism

PURPOSE

The pathogenesis of idiopathic hypogonadotropic hypogonadism (IHH) is genetically complex. The aims of this study were to investigate the genetic profile and clinical manifestation of IHH in a Chinese pedigree and to discover new IHH-associated genes.

METHODS

The first step was to follow up the clinical phenotype and therapeutic outcomes of the pedigree in university hospital. The second step was that mutation screening was performed in this pedigree and 100 healthy controls. The third step was to further verify the pathogenicity of the discovered rare sequencing variant (RSV) by functional experiments. Whole exome sequencing, Sanger sequencing, testicular volume (TV), semen analysis, assessment of cell migration and necroptosis were performed.

RESULTS

One heterozygous RSV (p.G517E) in CHL1 was identified in two male IHH patients and their mother in the pedigree, but not in healthy controls. All the three individuals exhibited olfactory impairment. hCG/hMG treatment significantly improved TV, serum testosterone and/or semen parameters of the two male patients. Functional analysis indicated that CHL1 significantly regulated GnRH neuronal cell line (GN11 cells) migration and necroptosis, with alteration of ERK1/2 activation, calcium loading, and transcription of RIPK3 and MLKL. However, the above processes were negatively influenced by the CHL1 RSV.

CONCLUSIONS

Our study reports the genetic relevance of CHL1 in IHH, and characterizes the phenotypic and therapeutic profiles in patients carrying the CHL1 RSV. CHL1 may act as a new IHH-associated gene, and should be taken into consideration in future investigations for this field.

Ultrafast X-Ray Diffraction Visualization of B1-B2 Phase Transition in KCl under Shock Compression

The classical B1(NaCl)↔B2(CsCl) transitions have been considered as a model for general structural phase transformations, and resolving corresponding phase transition mechanisms under high strain rate shock compression is critical to a fundamental understanding of phase transition dynamics. Here, we use subnanosecond synchrotron x-ray diffraction to visualize the lattice response of single-crystal KCl to planar shock compression. Complete B1-B2 orientation relations are revealed for KCl under shock compression along ⟨100⟩_{B1} and ⟨110⟩_{B1}; the orientation relations and transition mechanisms are anisotropic and can be described with the standard and modified Watanabe-Tokonami-Morimoto model, respectively, both involving interlayer sliding and intralayer ion rearrangement. The current study also establishes a paradigm for investigating solid-solid phase transitions under dynamic extremes with ultrafast synchrotron x-ray diffraction.

[Directed differentiation of porcine induced pluripotent stem cells into forebrain GABAergic neuron progenitors]

OBJECTIVE

To establish an efficient protocol for directed differentiation of miniature-swine induced pluripotent stem cells (iPSCs) into GABAergic progenitors in a chemically defined system.

OBJECTIVE

We adopted a two-stage protocol for inducing the differentiation of porcine iPSCs. In the first stage, embryoid bodies (EBs) derived from porcine iPSCs after 3 days of suspension culture were induced in neural induction medium (containing SB431542, DMH1 and FGF2) till day 12 to differentiate into primitive neuroepithelia cells (NECs). In the second stage, the primitive NECs were induced in neural induction medium (containing Pur and B27) to obtain neural rosettes, which further differentiated into GABAergic neuron progenitors on day 21. After labeling with CM-DiI, the progenitor cells were stereotactically transplanted into the substantia nigra (SN) of 6-OHDA-lesioned PD model rats, and the cell survival, migration and differentiation in vivo were observed.

OBJECTIVE

Porcine iPSCs could be passaged stably on the feeder cell layer and expressed the pluripotent stem cell markers OCT4, Nanog, SSEA1and TRA-160. Karyotype analysis demonstrated the absence of contamination by cells from other species. On day 12 of induced differentiation, the cells formed adherent colonies containing NECs in the form of neural rosettes, which expressed the neuroepithelial markers PAX6, SOX2 and Nestin and the neurite marker beta Ⅲ Tubulin (Tuj1). After induction for 21 days, the NECs differentiated into GABAergic neural progenitors highly expressing NKX2.1 and FOXG1. Eight weeks after transplantation, the iPSCs-iGABA progeniters survived in the striatum of the PD rats, where they differentiate into GABAergic neurons and TH+ neurons and significantly improved dyskinesia of the rats.

OBJECTIVE

The miniature-swine iPSCsderived GABA progenitors may serve as promising donor cells for neural grafting for treatment of neurodegenerative diseases.

[Survey on tobacco use and associated factors in population in Shandong province, 2016-2017]

Objective: To understand the status of tobacco use and related influencing factors in population in Shandong province. Methods: Stratified multi-stage cluster sampling was used to select respondents from 216 villages (communities) of 36 districts (counties) in Shandong province. Influencing factors on smoking were analyzed by logistic regression model. Results: The adequate sample size was 6 271 participants. After complex weighted, the current smoking prevalence was 23.93%,45.58% in males and 1.18% in females. The Public's smoking rates varied widely among different groups in the population. 45-64 age group had the highest smoking rate (25.07%). Smoking rates were substantially different in education levels, with the highest in junior high school (28.94%). The rate was higher in the rural area (24.98%) than that in the urban areas (23.08%). The average daily smoking rate was 20.23%. The average age of initiating smoking was 21.21 years. The average daily cigarette intake was 16.31 cigarettes. Among all the former and current smokers, the quitting rate was 20.79%. Multiple logistic regression model analysis showed that gender, age, occupation, region, and health knowledge score were correlated with smoking behavior. The current smoking rate of men was much higher than that of women (OR=49.625, 95%CI: 37.832-65.093). The current smoking rate in 45-64 age group was higher than that in the 15-24 age group (OR=1.830, 95%CI: 1.048-3.194). The current smoking rate of medical (OR=0.403, 95%CI: 0.187-0.866) and retired personnel (OR=0.648, 95%CI: 0.481-0.873) were lower than those engaging in agriculture, forestry, animal husbandry and the fishery ,respectively. The prevalence of residents living in the central part showed lower rate on current smoking than that in the eastern region (OR=0.724, 95%CI: 0.606-0.865). The current smoking prevalence of smoke hazard in 1-3 score group was higher than that in the group with 4-6 score (OR=1.432, 95%CI: 1.240-1.654). Conclusions: Smoking rate in adults in Shandong remained stable and at a high level. Comprehensive intervention measures such as tobacco control and health education should be carried out to reduce the smoking rate.

[Preparation of doxorubicin-loaded metallic organic nanoparticles and their effect for enhancing efficacy of high-intensity focused ultrasound therapy in tumor-bearing mice]

OBJECTIVE

To prepare metallic organic nanoparticles that produce synergistic effect in high-intensity focused ultrasound (HIFU) therapy of tumors.

OBJECTIVE

Glucose oxidase (GOD), MnO₂, ferric iron (Fe³⁺) and doxorubicin (DOX) were self-assembled by physical adsorption with previously prepared manganese dioxide (MnO₂) nanoparticles to obtain GOD-MnO₂-Fe³⁺-DOX nanoparticles (GMFD NPs). HepG2 tumor-bearing nude mouse models were given intravenous injections of normal saline or GMFD NPs followed 4 h later by HIFU at the acoustic power of 90 W with a total treatment time of 3 s. The changes of tumor gray value before and after HIFU irradiation were observed and 24 h after HIFU irradiation, coagulation necrosis in the tumor tissues was examined; the histological changes of the tumor tissues were observed with HE staining.

OBJECTIVE

We successfully prepared GMFD NPs, which had an average particle size of 131.23±0.84 nm with a surface potential of 21.87±1.72 mV. GMFD NPs, with a drug loading rate of 40.18%, was capable of releasing more than 77.2% of the loaded DOX within 4 h in acidic environment. In the tumor-bearing mouse models, HIFU irradiation following GMFD NP injection, as compared with saline injection, resulted in significantly enhanced gray value of the tumor (25.5±4.5 vs 18.7±3.9, P=0.04) and greater volume of coagulation necrosis (105.80 ± 1.21 mm³ vs 38.02 ± 0.34 mm³). The energy efficiency factor (EEF) was significantly lower in GMFD NPs group than in saline group (1.79 vs 4.97, P < 0.001).

OBJECTIVE

GMFD NPs prepared in this study can enhance tumor ablation efficacy of HIFU and release DOX for further treatment of the residual tumor tissue in mice.

[Clinical study of dienogest in the treatment of refractory endometriosis-associated pain]

Objective: To evaluate the efficacy and safety of dienogest (DNG) in the treatment of refractory endometriosis-associated pain (REAP). Methods: In this study, REAP was defined according to the following criteria: (1) the pain duration was ≥12 months and visual analogue scale (VAS)≥60 mm; (2) the previous treatments with over two medicines like oral contraceptives and levonorgestrel-releasing intrauterine system failed to achieve satisfactory relief of pain, with VAS reduction less than 50%; with gonadotropin-releasing hormone agonist or mifepristone, the pain could be controlled temporarily, but it recurred after discontinuation of medicines; (3) the pain could not be relieved by surgery or even repeated surgeries. In the present study, 48 patients with REAP were treated with DNG 2 mg/day orally and the clinical outcomes were retrospectively analyzed. The VAS scores, levels of CA₁₂₅, estradiol, FSH, LH and changes in the size of endometriotic lesions before and after treatment were compared respectively. The side effects were also analyzed. Results: The average duration of DNG treatment was (20.1±12.8) months. After 3 months of medication, the VAS score was significantly reduced from (77.9±15.8) mm to (20.8±10.7) mm (P<0.01), and CA₁₂₅ level was significantly reduced from (95±139) kU/L to (38±45) kU/L (P<0.05). The effects were maintained with continuation of DNG treatment. Endometriotic lesions tended to shrink, after 12 months of DNG treatment, the size of ovarian endometriomas was reduced significantly from (3.1±1.0) cm to (1.9±1.2) cm (P<0.05). The mean level of estradiol was maintained at 124.82-221.04 pmol/L and levels of FSH and LH did not change significantly during the treatment. The major side effect was irregular bleeding (75%, 36/48). Conclusions: DNG could effectively relieve REAP and is a well-tolerated therapy. It may supply an alternative option for patients with REAP.

SP rTaTME: initial clinical experience with single-port robotic transanal total mesorectal excision (SP rTaTME)

BACKGROUND

The technical difficulty and steep learning curve of transanal total mesorectal excision (taTME) has limited widespread adoption. The single-port (SP) daVinci robot is designed to facilitate single-incision and natural-orifice transluminal endoscopic surgery (NOTES). This paper describes the first clinical experience of single-port robotic taTME (SP rTaTME).

METHODS

This was a prospective study on consecutive patients with rectal cancer who underwent SP rTaTME proctosigmoidectomy with handsewn coloanal anastomosis in December 2018 and January 2019. The primary outcome was technical feasibility of the procedure. The secondary outcomes include blood loss, intraoperative complications, length of hospital stay, quality of the TME specimen, short- and long-term morbidity and mortality, as well as short-term oncologic follow -up.

RESULTS

There were two patients, a 48-year-old male and a 38-year-old female. Both operations were completed successfully without complications or conversion. Estimated blood loss was 200 mL and 130 mL. In both cases the TME was completed transanally using the SP robot. In the first patient, the abdominal portion was completed through an abdominal single-incision; in the second patient the operation was entirely performed transanally as a pure NOTES procedure. In both cases, the final pathology report showed a complete TME with negative margins. Patients were discharged on postoperative day 3 and 4,respectively. There was no long-term morbidity or mortality.

CONCLUSIONS

SP rTaTME is feasible and can be safely performed. It provides excellent optics and dexterity to work in a limited space. Future studies are required to further define the safety profile and the ultimate utility of the SP robot for taTME.

MicroRNA-133a-5p inhibiting metastatic capacity of renal clear cell carcinoma through regulating MON2

OBJECTIVE

We aimed at analyzing the correlation between microRNA-133a-5p expression and clinical pathological parameters in patients with clear cell renal cell carcinoma (ccRCC) and exploring the mechanism by which microRNA-133a-5p affects the biological behavior of ccRCC cells.

PATIENTS AND METHODS

MicroRNA-133a-5p expression in ccRCC tissues and cell lines were examined by quantitative real-time polymerase chain reaction (qRT-PCR), and the relationship between ATG14 expression and clinicopathological parameters of ccRCC patients was analyzed. A control group (NC mimic) and a microRNA-133a-5p overexpression group (microRNA-133a-5p mimic) were set in the ccRCC cell lines ACHN and 786-O, respectively. The impacts of microRNA-133a-5p on the proliferation and invasion of ccRCC cells were evaluated through performing Cell Counting Kit-8 (CCK-8) and transwell tests, respectively. We further explored the interaction between microRNA-133a-5p and its downstream target gene WNK2 by bioinformatics analysis and Luciferase assay.

RESULTS

Both in ccRCC tissues and cell lines, microRNA-133a-5p showed a significantly reduced expression, which could be used to predict poor prognosis of ccRCC patients. Upregulation of microRNA-133a-5p markedly blunted the proliferation and migratory capacities of HCC cells. Bioinformatics analysis suggested that microRNA-133a-5p can target MON2. In addition, qPCR assay indicated an increased expression of MON2 in ccRCC cell lines and tissues, which was negatively correlated with microRNA-133a-5p. Finally, in vitro cell reverse experiments suggested that overexpression of MON2 counteracted the inhibitory effects of overexpression of microRNA-133a-5p on the proliferation and metastatic capacity of ccRCC.

CONCLUSIONS

This study suggests that the reduced expression of microRNA-133a-5p in ccRCC tissue specimens can predict poor prognosis of ccRCC patients. At the same time, microRNA-133a-5p may suppress the proliferation capacity and metastasis of ccRCC cells by acting on MON2.

Pulsed Microfluid Force-Based On-Chip Modular Fabrication for Liver Lobule-Like 3D Cellular Models

In vitro three-dimensional (3D) cellular models with native tissue-like architectures and functions have potential as alternatives to human tissues in regenerative medicine and drug discovery. However, it is difficult to replicate liver constructs that mimic in vivo microenvironments using current approaches in tissue engineering because of the vessel-embedded 3D structure and complex cell distribution of the liver. This paper reports a pulsed microflow-based on-chip 3D assembly method to construct 3D liver lobule-like models that replicate the spatial structure and functions of the liver lobule. The heterogeneous cell-laden assembly units with hierarchical cell distribution are fabricated through multistep photopatterning of different cell-laden hydrogels. Through fluid force interaction by pulsed microflow, the hierarchical assembly units are driven to a stack, layer by layer, and thus spatially assemble into 3D cellular models in the closed liquid chamber of the assembly chip. The 3D models with liver lobule-like hexagonal morphology and radial cell distribution allow the dynamic perfusion culture to maintain high cell viability and functional expression during long-term culture in vitro. These results demonstrate that the fabricated 3D liver lobule-like models are promising for drug testing and the study of individual diagnoses and treatments.

Observation of a Near-Threshold Structure in the K^{+} Recoil-Mass Spectra in e^{+}e^{-}→K^{+}(D_{s}^{-}D^{*0}+D_{s}^{*-}D^{0})

We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} based on e^{+}e^{-} annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7  fb^{-1}. An excess of events over the known contributions of the conventional charmed mesons is observed near the D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrt[s]=4.681  GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1)  MeV/c^{2} and (12.8_{-4.4}^{+5.3}±3.0)  MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3  σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.

Model-Independent Determination of the Spin of the Ω^{-} and Its Polarization Alignment in ψ(3686)→Ω^{-}Ω[over ¯]^{+}

We present an analysis of the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} (Ω^{-}→K^{-}Λ, Ω[over ¯]^{+}→K^{+}Λ[over ¯], Λ→pπ^{-}, Λ[over ¯]→p[over ¯]π^{+}) based on a dataset of 448×10^{6}  ψ(3686) decays collected with the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} and the decay parameters of the subsequent decay Ω^{-}→K^{-}Λ (Ω[over ¯]^{+}→K^{+}Λ[over ¯]) are measured for the first time by a fit to the angular distribution of the complete decay chain, and the spin of the Ω^{-} is determined to be 3/2 for the first time since its discovery more than 50 years ago.

Soft X-ray and ENA Imaging of the Earth's Dayside Magnetosphere

The LEXI and SMILE missions will provide soft X-ray images of the Earth's magnetosheath and cusps after their anticipated launch in 2023 and 2024, respectively. The IBEX mission showed the potential of an Energetic Neutral Atom (ENA) instrument to image dayside magnetosheath and cusps, albeit over the long hours required to raster an image with a single pixel imager. Thus, it is timely to discuss the two imaging techniques and relevant science topics. We simulate soft X-ray and low-ENA images that might be observed by a virtual spacecraft during two interesting solar wind scenarios: a southward turning of the interplanetary magnetic field and a sudden enhancement of the solar wind dynamic pressure. We employ the OpenGGCM global magnetohydrodynamics model and a simple exospheric neutral density model for these calculations. Both the magnetosheath and the cusps generate strong soft X-rays and ENA signals that can be used to extract the locations and motions of the bow shock and magnetopause. Magnetopause erosion corresponds closely to the enhancement of dayside reconnection rate obtained from the OpenGGCM model, indicating that images can be used to understand global-scale magnetopause reconnection. When dayside imagers are installed with high-ENA inner-magnetosphere and FUV/UV aurora imagers, we can trace the solar wind energy flow from the bow shock to the magnetosphere and then to the ionosphere in a self-standing manner without relying upon other observatories. Soft X-ray and/or ENA imagers can also unveil the dayside exosphere density structure and its response to space weather.

Recent Advances in Developing Lanthanide Metal-Organic Frameworks for Ratiometric Fluorescent Sensing

Fluorescent probes have attracted special attention in developing optical sensor systems due to their reliable and rapid fluorescent response upon reaction with the analyte. Comparing to traditional fluorescent sensing systems that employ the intensity of only a single emission, ratiometric fluorescent sensors exhibit higher sensitivity and allow fast visual screening of analytes because of quantitatively analyzing analytes through the emission intensity ratio at two or more wavelengths. Lanthanide metal–organic frameworks (LnMOFs) are highly designable multifunctional luminescent materials as lanthanide ions, organic ligands, and guest metal ions or chromophores are all potential sources for luminescence. They thus have been widely employed as ratiometric fluorescent sensors. This mini review summarized the basic concept, optical features, construction strategies, and the ratiometric fluorescent sensing mechanisms of dual-emitting LnMOFs. The review ends with a discussion on the prospects, challenges, and new direction in designing LnMOF-based ratiometric fluorescent sensors.

Correlation between Sarcopenia and Arteriosclerosis in Elderly Community Dwellers: A Multicenter Study

BACKGROUND

Evidence suggests that arteriosclerosis and sarcopenia (decreased muscle mass) share some of their many causes. However, after controlling for confounding factors, it is unclear whether the presence of arteriosclerosis correlates with sarcopenia.

OBJECTIVES

The aim of this paper is to explore whether sarcopenia is associated with arteriosclerosis.

DESIGN

A multicenter cross-sectional community-based study.

MATERIALS AND METHODS

A total of 2511 elderly subjects from six Chinese community health service centers in Anhui province were surveyed through an e-health promotion system to collect basic data and measurements of brachial-ankle pulse wave (baPWV), body composition, and handgrip strength (HGS). Pearson's correlation and binary logistic regression analyses were performed to identify associations between sarcopenia and high baPWV.

RESULTS

The prevalence rates of sarcopenia were 12.9% in men and 15.3% in women according to the 2019 standard of Asian Working Group for Sarcopenia. Among subjects with high baPWV, the proportion of sarcopenia was higher compared to those with normal baPWV (men: 17.7% vs. 3.7%; women: 20.4% vs. 4.9%, both p<0.001). Binary logistic regression analysis revealed that sarcopenia was associated with high baPWV (p<0.0001, odds ratio=1.619) after adjusting for confounding factors. HGS slightly and negatively correlated with baPWV (-0.19 in men and -0.18 in women).

CONCLUSIONS

The intertwined pathophysiological mechanisms shared by arteriosclerosis and sarcopenia are potential targets for future interventions to reduce morbimortality in subjects with both disorders. Upcoming prospective studies and clinical trials are expected to advance these findings.

Efficacy of utidelone plus capecitabine versus capecitabine for heavily pretreated, anthracycline- and taxane-refractory metastatic breast cancer: final analysis of overall survival in a phase III randomised controlled trial

BACKGROUND

Primary analysis of the phase III trial BG01-1323L demonstrated that utidelone plus capecitabine significantly improved progression-free survival (PFS) and overall response rate (ORR) versus capecitabine alone in heavily-pretreated patients with metastatic breast cancer (MBC). Here, we report the final overall survival (OS) analysis and updates of other endpoints.

PATIENTS AND METHODS

In total, 405 patients were randomised 2:1 to receive utidelone (30 mg/m² IV daily, days 1-5, over 90 min) plus capecitabine (1000 mg/m² orally b.i.d., days 1-14) or capecitabine alone (1250 mg/m² orally b.i.d., days 1-14) every 21 days. The secondary endpoint, OS, was estimated using the Kaplan-Meier product-limit approach at a two-sided alpha level of 0.05 after the prespecified 310 death events had been reached. Exploratory analyses of the primary endpoint, PFS, and the secondary endpoint, ORR, were also done. Safety was analysed in patients who had at least one dose of study drug.

RESULTS

At the final OS analysis, the median duration of follow-up was 19.6 months in the utidelone plus capecitabine group and 15.4 months in the capecitabine alone group. In the intention-to-treat population, 313 deaths had occurred at data cut-off, 203 of 270 patients in the combination group and 110 of 135 in the monotherapy group. Median OS in the combination group was 19.8 months compared with 16.0 months in the monotherapy group [hazard ratio (HR) = 0.75, 95% confidence intervals (CI) 0.59-0.94, P = 0.0142]. The updated analysis of PFS and ORR showed that the combination therapy remained superior to monotherapy. Safety results were similar to those previously reported with respect to incidence, severity and specificity. No late-emerging toxicities or new safety concerns occurred.

CONCLUSIONS

For heavily-pretreated, anthracycline- and taxane-resistant MBC patients, utidelone plus capecitabine significantly improved OS versus capecitabine alone. These results support the use of utidelone plus capecitabine as a novel therapeutic regimen for patients with MBC.

LncRNA MALAT1 knockdown alleviates myocardial apoptosis in rats with myocardial ischemia-reperfusion through activating PI3K/AKT signaling pathway

OBJECTIVE

To observe the effect of long non-coding ribonucleic acid metastasis-associated lung adenocarcinoma transcript 1 (lncRNA MALAT1) on the myocardial ischemia-reperfusion (I/R) injury in rats and to explore its potential mechanism, to provide certain references for clinical prevention and treatment of myocardial I/R injury.

MATERIALS AND METHODS

A total of 60 male Wistar rats were randomly divided into the Control group (n=20), I/R group (n=20) and I/R + MALAT1 small-interfering RNA (siRNA) group (n=20) using a random number table. The I/R model was established through recanalization after ligation of left anterior descending coronary artery (LAD), and the MALAT1 knockdown model was established via tail intravenous injection of MALAT1 siRNA in the I/R + MALAT1 siRNA group. The ejection fraction (EF%) and fractional shortening (FS%) of rats in each group were detected via echocardiography and the infarction area in each group was detected using 2,3,5-triphenyl tetrazolium chloride (TTC) assay. Moreover, the morphological changes in myocardial cells in each group were detected via hematoxylin-eosin (H&E) staining, and the myocardial apoptosis level was detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. At the same time, the expression levels of the anti-apoptotic protein B-cell lymphoma-2 (Bcl-2) and pro-apoptotic protein Bcl-2 associated X protein (Bax) in myocardial tissues in each group were determined via Western blotting. Finally, the effect of MALAT1 knockdown on the phosphatidylinositol 3-hydroxy kinase/protein kinase B (PI3K/AKT) protein expression was detected via Western blotting.

RESULTS

The expression level of lncRNA MALAT1 in myocardial tissues was significantly higher in the I/R group than that in the Control group (p<0.05). The MALAT1 knockdown could significantly improve the cardiac insufficiency caused by I/R injury, and increase both EF% and FS% in rats (p<0.05). In addition, the MALAT1 knockdown could markedly inhibit myocardial infarction caused by I/R injury and reduce the infarction area from (62.12 ± 1.29) to (27.66 ± 3.58; p<0.05). The results of the H&E staining showed that the myofilaments were arranged more orderly, the degrees of degradation and necrosis were lower and the cellular edema was significantly alleviated in the I/R + MALAT1 siRNA group compared with those in the I/R group. According to the results of TUNEL staining, the rats in I/R + MALAT1 siRNA group had a markedly lower level of myocardial apoptosis than the I/R group (p<0.05), and the Bax/Bcl-2 ratio also remarkably declined in the I/R + MALAT1 siRNA group (p<0.05). Furthermore, the results of Western blotting revealed that MALAT1 siRNA could significantly reverse the I/R injury-induced inhibition on the AKT phosphorylation (p<0.05).

CONCLUSIONS

The MALAT1 knockdown can markedly improve the I/R-induced myocardial injury and promote the cardiac function of rats, whose mechanism may be related to the activation of the AKT signaling pathway by MALAT1 siRNA. Therefore, lncRNA MALAT1 is expected to be a new therapeutic target for myocardial I/R injury.