Working memory deficits in Parkinson's disease mouse model / 中国药理学与毒理学杂志

OBJECTIVE Parkinson's disease(PD)is a progressive neurodegenerative disease clinically char-acterized by dyskinesia,tremor,rigidity,abnormal gait,whereas 90%of patients with PD suffer from defects of the sense of smell before the appearance of the motor dysfunctions.However,the mechanism of olfactory disor-der is still not clear.METHODS We utilized olfaction based delayed paired association task in head-fixed mice.We focused on functional role of neural circuit using opto-genetic techniques.In addition,we viewed the synaptic transmission by slice physiological recording and count-ed the cell number of targeted circuits.RESULTS AND CONCLUSION In our experiments,olfactory working memory impairments were found in the PD mice,and the working memory impairment appeared before motor dys-functions.Furthermore,we also investigated the functional role of neural circuit for olfactory working memory in PD mice.Meanwhile,the excitatory post synaptic currents were decreased as a result of presynaptic release proba-bility suppression in PD mice.However cell loss wasn't found in working memory related circuit recently.These will provide a new idea of clinic diagnosis for PD.

Construction of an Analysis Model of mRNA Markers in Menstrual Blood Based on Naïve Bayes and Multivariate Logistic Regression Methods / 法医学杂志

OBJECTIVES@#To establish the menstrual blood identification model based on Naïve Bayes and multivariate logistic regression methods by using specific mRNA markers in menstrual blood detection technology combined with statistical methods, and to quantitatively distinguish menstrual blood from other body fluids.@*METHODS@#Body fluids including 86 menstrual blood, 48 peripheral blood, 48 vaginal secretions, 24 semen and 24 saliva samples were collected. RNA of the samples was extracted and cDNA was obtained by reverse transcription. Five menstrual blood-specific markers including members of the matrix metalloproteinase (MMP) family MMP3, MMP7, MMP11, progestogens associated endometrial protein (PAEP) and stanniocalcin-1 (STC1) were amplified and analyzed by electrophoresis. The results were analyzed by Naïve Bayes and multivariate logistic regression.@*RESULTS@#The accuracy of the classification model constructed was 88.37% by Naïve Bayes and 91.86% by multivariate logistic regression. In non-menstrual blood samples, the distinguishing accuracy of peripheral blood, saliva and semen was generally higher than 90%, while the distinguishing accuracy of vaginal secretions was lower, which were 16.67% and 33.33%, respectively.@*CONCLUSIONS@#The mRNA detection technology combined with statistical methods can be used to establish a classification and discrimination model for menstrual blood, which can distignuish the menstrual blood and other body fluids, and quantitative description of analysis results, which has a certain application value in body fluid stain identification.

Thromboelastography in guiding preventive platelet transfusion in patients with haematologic diseases.

OBJECTIVE: This study analysed the relationships between the main thromboelastography (TEG) parameters, the platelet (PLT) count and clinical bleeding in patients with blood diseases. We explored the threshold of the relevant parameters in the pathological condition of bleeding, aiming to scientifically guide clinical prophylactic PLT transfusion. METHODS: In total, 268 patients with clear diagnoses of blood diseases and thrombocytopenia were enrolled and divided into five groups, A, B, C, D and E, corresponding to PLT counts of 0-10 × 109 /L, 11-20 × 109 /L, 21-30 × 109 /L, 31-50 × 109 /L and 51-100 × 109 /L, respectively. TEG and routine blood testing were performed simultaneously, the main TEG parameters and the PLT count were analysed, and the thresholds of the main TEG parameters in each group when the patient had bleeding were obtained. RESULTS: The maximum amplitude (MA) in groups A, B and C increased gradually, with a significant difference between each pair of these groups (P < 0.05). In groups A, B, C, D and E, the corresponding MA at the time of bleeding was 43.5 mm, 39.6 mm, 38.0 mm, 35.2 mm and 50.5 mm, respectively, with statistically significant differences (P < 0.05). CONCLUSIONS: The MA can be used as a reference indicator for preventive PLT transfusion to a certain extent. When the PLT count is within different ranges, the MA threshold for preventive PLT transfusion also differs. It is recommended that different PLT counts be correlated with different MA thresholds to guide clinical prophylactic PLT transfusion.

Quantitative evaluation of the dynamic changes of mitral annulus in patients with degenerative mitral regurgitation by three-dimensional echocardiography / 中华超声影像学杂志

Objective:To quantitatively analyze the static geometric structure and dynamic changes of the mitral annulus(MA) in patients with degenerative mitral regurgitation (DMR) by three-dimensional transthoracic echocardiography.Methods:Thirty-five patients with DMR (both mitral valve prolapse and Barlow) were collected as DMR group in Yunnan Fuwai Cardiovascular Disease Hospital from August 2019 to March 2021, and 42 healthy volunteers were selected as control group during the same period. The mitral annulus area (MAA), mitral annulus perimeter (MAP), mitral annulus anterolateral-posteromedial diameter (DALPM), anteroposterior diameter (DAP), non-planar angle (NPA), mitral annulus height (AH), and the ratio of height to intercommissural diameter (AHCWR) were measured during the late-diastole, early-systole, mid-systole and late-systole, and the systolic change fractions of the above parameters were calculated. The differences of static structure and dynamic change of MA between the two groups were compared, and the characteristics of dynamic change of MA in the whole cardiac cycle were analyzed.Results:Static structure: MAA, MAP, DAP and DALPM in DMR group were higher than those in control group during the whole cardiac cycle, and the differences were statistically significant (all P<0.05). Compared with the control group, the saddle structure in DMR group were flattened in the middle and late contraction stages (AHCWR: 0.17±0.01 vs 0.21±0.01 and 0.15±0.01 vs 0.23±0.01, both P<0.05), while the saddle structure was relatively preserved in the rest of the contraction stage. Dynamic changes: Presystole contraction (MAA, MAP, DAP, DALPM decreased, all P<0.05) were appeared durng the late-diastole and early-systole in the control group, and saddle shape deepened (NPA decreased, AH and AHCWR increased, all P<0.05). Compared with the control group, presystole MA contraction and saddle deepening disappeared in DMR group (there were no significant differences in all MA parameters between late-diastole and early-systole, all P>0.05). The systolic dynamic changes were weaker and impaired when compared with the control group, which showed that the systolic change scores of DALPM, NPA and AHCWR were lower than those of the control group (all P<0.05). There were no statistical differences in the 4 time phases of MA parameters except DAP (all P>0.05). Conclusions:The saddle-shape structure of MA in normal subjects is obvious, and the dynamic change of MA in the cardiac cycle is significant, with obvious contraction before contraction and saddle-shape deepening. The saddle structure of DMR patient is flattened in the middle and late systolic period, and the MA kinetic energy of DMR patient is weakened throughout the cardiac cycle, the contraction phenomenon disappeared before contraction, and the dynamic change of systolic period is impaired to varying degrees.

Cathepsin L plays a key role in SARS-CoV-2 infection in humans and humanized mice and is a promising target for new drug development

To discover new drugs to combat coronavirus disease 2019 (COVID-19), an understanding of the molecular basis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is urgently needed. Here, for the first time, we report the crucial role of cathepsin L (CTSL) in patients with COVID-19. The circulating level of CTSL was elevated and was positively correlated with disease course and severity in COVID-19 patients. Correspondingly, SARS-CoV-2 pseudovirus infection increased CTSL expression in human cell lines and human ACE2 transgenic mice, while CTSL overexpression, in turn, enhanced pseudovirus infection. CTSL functionally cleaved the SARS-CoV-2 spike protein and enhanced virus entry, as evidenced by CTSL overexpression and knockdown in vitro and application of CTSL inhibitor drugs in vivo. Furthermore, amantadine, a licensed anti-influenza drug, significantly inhibited CTSL activity and prevented SARS-CoV-2 pseudovirus infection. Therefore, CTSL is a promising target for new anti-COVID-19 drug development.

Autophagic blockage by bismuth sulfide nanoparticles inhibits migration and invasion of HepG2 cells.

The biological effects of nanoparticles are of great importance for the in-depth understanding of safety issues in biomedical applications. Induction of autophagy is a cellular response after nanoparticle exposure. Bismuth sulfide nanoparticles (Bi2S3 NPs) are often used as a CT contrast agent because of their excellent photoelectric conversion ability. Yet there has been no previous detailed study other than a cell toxicity assessment. In this study, three types of Bi2S3 NPs with different shapes (Bi2S3 nano rods (BSNR), hollow microsphere Bi2S3 NPs (BSHS) and urchin-like hollow microsphere Bi2S3 NPs (ULBSHS)) were used to evaluatecytotoxicity, autophagy induction, cell migration and invasion in human hepatocellular carcinoma cells (HepG2). Results showed that all three Bi2S3 NPs lead to blockage in autophagic flux, causing p62 protein accumulation. The cell death caused by these Bi2S3 NPs is proved to be autophagy related, rather than related to apoptosis. Moreover, Bi2S3 NPs can reduce the migration and invasion in HepG2 cells in an autophagy-dependent manner. ULBSHS is the most cytotoxic among three Bi2S3 NPs and has the best tumor metastasis suppression. These results demonstrated that, even with relatively low toxicity of Bi2S3 NPs, autophagy blockage may still substantially influence cell fate and thus significantly impact their biomedical applications, and that surface topography is a key factor regulating their biological response.

Withaferin A protecting against high fat diet induced obesity by inducing white adipose tissue browning / 解剖学报

[ Abstract] Objective To investigate the protective effect of withaferin A (WA) against high fat diet induced obesity and its associated mechanism. Methods C57BL / 6 J mice at 8-week of age were divided into two groups. The mice were fed with high fat diet (HFD) and were given an intraperitoneal injection of WA or DMSO (solvent control) . The body weight and food intake of the mice were monitored. One week later, inguinal white adipose tissue (iWAT), interscapular brown adipose tissue (BAT), epididymal white adipose tissue (eWAT) and retroperitoneal white adipose tissue (rWAT) were collected and weighed. Expression levels of the genes associated with white adipose browning were detected in iWAT. HE staining was applied to observe the morphological changes of iWAT. Results The data showed that body weight and fat weight in WA group were significantly lower than those in the control group, and the food intake was not changed significantly. Real-time PCR analysis showed that the expression level of browning related genes in iWAT of the WA group was significantly increased. The result from Western blotting analysis showed that the protein levels of uncoupling protein 1 (UCP1) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) increased significantly in iWAT of the WA group. The typical morphological change of adipose browning, such as the multilocular adipocytes was observed in inguinal white adipose tissue of the mice treated with WA by using HE staining and mmunofluorescence assay. Conclusion Taken together, these observations indicate that withaferin A can protect the mice from high fat diet induced obesity by promoting white adipose tissue browning.

Emerging relationship between RNA helicases and autophagy / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

RNA helicases, the largest family of proteins that participate in RNA metabolism, stabilize the intracellular environment through various processes, such as translation and pre-RNA splicing. These proteins are also involved in some diseases, such as cancers and viral diseases. Autophagy, a self-digestive and cytoprotective trafficking process in which superfluous organelles and cellular garbage are degraded to stabilize the internal environment or maintain basic cellular survival, is associated with human diseases. Interestingly, similar to autophagy, RNA helicases play important roles in maintaining cellular homeostasis and are related to many types of diseases. According to recent studies, RNA helicases are closely related to autophagy, participate in regulating autophagy, or serve as a bridge between autophagy and other cellular activities that widely regulate some pathophysiological processes or the development and progression of diseases. Here, we summarize the most recent studies to understand how RNA helicases function as regulatory proteins and determine their association with autophagy in various diseases.

Emerging relationship between RNA helicases and autophagy / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

RNA helicases, the largest family of proteins that participate in RNA metabolism, stabilize the intracellular environment through various processes, such as translation and pre-RNA splicing. These proteins are also involved in some diseases, such as cancers and viral diseases. Autophagy, a self-digestive and cytoprotective trafficking process in which superfluous organelles and cellular garbage are degraded to stabilize the internal environment or maintain basic cellular survival, is associated with human diseases. Interestingly, similar to autophagy, RNA helicases play important roles in maintaining cellular homeostasis and are related to many types of diseases. According to recent studies, RNA helicases are closely related to autophagy, participate in regulating autophagy, or serve as a bridge between autophagy and other cellular activities that widely regulate some pathophysiological processes or the development and progression of diseases. Here, we summarize the most recent studies to understand how RNA helicases function as regulatory proteins and determine their association with autophagy in various diseases.

Evaluation of the Prediction Performance of Population Pharmacokinetic Models of Sodium Valproate in Epileptic Children in China / 中国药学杂志

OBJECTIVE: To compare all published sodium valproate population pharmacokinetic models of epileptic children in China and assess them by external validation to determine their predictive performance. METHODS: The published population pharmacokinetic model of sodium valproate in children with epilepsy in China was collected by database retrieval. By retrospectively collecting patients' information, we performed an external validation to evaluate the power of prediction. RESULTS: Four sodium valproate models were published before. The external validation of 101 samples showed that the MPE, MAE, RMSE of the four model were similar. All of them showed good adequacy between predicted concentrations and observed concentrations. Comparing with other models, the model established by Ding has better prediction error coincidence rate in most interval, which is more targeted for the prediction of individualized dosage regimen for epileptic children in our hospital. However, the overall prediction accuracy of the four models is not significantly different. CONCLUSION: By the evaluation of four published population pharmacokinetic models of sodium valproate model B performs better than others, while the overall accuracy of the four models did not differ much. Racial difference may be an important factor affecting the accuracy of the model, which needs to be further explored in subsequent studies.

Clinical progress of mesenchymal stem cells in the treatment of osteoarthritis / 中国综合临床

Osteoarthritis (OA) is slow progressive disease with destruction of articular cartilage and hypertrophy of subchondral bone.The elderly are the most common patients,usually treated by joint surgery.OA patients often undergo total joint replacement.The risk andhigh cost of joint replacement prompt researchers to use multi-potential mesenchymal stem cells to repair full-thickness articular cartilage.Mesenchyma Stem Cells (MSCs) are stromal cells that can differentiate into bone,fat and chondrocytes.MSCs exist in bone marrow and fat.Bone Marrow Mesenchymal Stem Cells (BMSCs) can also be found in synovial joints.MSCs affect the progress of OA.MSCs can be isolated and proliferated in vitro and applied in clinical trials.Current clinical trials are still at an early stage.The primary purpose is to evaluate the safety,feasibility and effectiveness.This article reviews recent progress in clinical trials of MSCs repair of OA.

Anti-Hypertensive Action of Fenofibrate via UCP2 Upregulation Mediated by PPAR Activation in Baroreflex Afferent Pathway / 神经科学通报·英文版

Fenofibrate, an agonist for peroxisome proliferator-activated receptor alpha (PPAR-α), lowers blood pressure, but whether this action is mediated via baroreflex afferents has not been elucidated. In this study, the distribution of PPAR-α and PPAR-γ was assessed in the nodose ganglion (NG) and the nucleus of the solitary tract (NTS). Hypertension induced by drinking high fructose (HFD) was reduced, along with complete restoration of impaired baroreceptor sensitivity, by chronic treatment with fenofibrate. The molecular data also showed that both PPAR-α and PPAR-γ were dramatically up-regulated in the NG and NTS of the HFD group. Expression of the downstream signaling molecule of PPAR-α, the mitochondrial uncoupling protein 2 (UCP2), was up-regulated in the baroreflex afferent pathway under similar experimental conditions, along with amelioration of reduced superoxide dismutase activity and increased superoxide in HFD rats. These results suggest that chronic treatment with fenofibrate plays a crucial role in the neural control of blood pressure by improving baroreflex afferent function due at least partially to PPAR-mediated up-regulation of UCP2 expression and reduction of oxidative stress.

Comparison of volatile profiles and bioactive components of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain measured by GC-MS and HPLC / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

To explore the volatile profiles and the contents of ten bioactive components (polyphenols and caffeine) of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain, 17 samples of three tea varieties were analyzed by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and high-performance liquid chromatography (HPLC). A total of 75 volatile components were tentatively identified. Laomaner (LME), Laobanzhang (LBZ), and other teas on Bulang Mountain (BL) contained 70, 53, and 71 volatile compounds, respectively. Among the volatile compounds, alcohols (30.2%-45.8%), hydrocarbons (13.7%-17.5%), and ketones (12.4%-23.4%) were qualitatively the most dominant volatile compounds in the different tea varieties. The average content of polyphenol was highest in LME (102.1 mg/g), followed by BL (98.7 mg/g) and LBZ (88.0 mg/g), while caffeine showed the opposite trend, 27.3 mg/g in LME, 33.5 mg/g in BL, and 38.1 mg/g in LBZ. Principal component analysis applied to both the volatile compounds and ten bioactive components showed a poor separation of samples according to varieties, while partial least squares-discriminant analysis (PLS-DA) showed satisfactory discrimination. Thirty-four volatile components and five bioactive compounds were selected as major discriminators (variable importance in projection (VIP) >1) among the tea varieties. These results suggest that chromatographic data combined with multivariate analysis could provide a useful technique to characterize and distinguish the sun-dried Pu-erh tea leaves from ancient tea varieties on Bulang Mountain.

Progresses of three-dimensional echocardiography quantitative evaluation in valve structure and function and degree of regurgitation for patients with mitral regurgitation / 中国医学影像技术

Mitral regurgitation (MR) is one of the most common valve lesions. Echocardiography can effectively evaluate the valve structure and reflux, and provide a basis for clinical diagnosis and treatment. Compared with conventional echocardiography, the quantitative technique of three-dimensional echocardiography can better describe the valve structure and function, and more accurately assess the degree of reflux, which is of great significance for clinical treatment, decisions and disease risk stratification. The research progresses of quantitative evaluation of valve structure and reflux in patients with mitral regurgitation by three-dimensional echocardiography were reviewed in this article.

Biocompatible Fe3+-TA coordination complex with high photothermal conversion efficiency for ablation of cancer cells.

Near-infrared (NIR) light absorbing nanomaterials, which can convert light to heat energy, have great prospects in biomedical applications. In the current work, Fe3+-TA (Tannic Acid) coordination complex formed by simple mixing of tannic acid and FeCl3 solutions was explored as a novel photothermal agent. Due to the strong absorbance in the near-infrared region induced by the coordination effect between TA molecule and Fe3+ ion, the as-prepared Fe3+-TA complex exhibited excellent photothermal performance with high photothermal conversion efficiency of 77.3% and high photothermal stability. Upon the exposure to Fe3+-TA aqueous dispersions with a concentration of 0.125 mg/mL, the cell mortality of HeLa cells was more than 85% after being irradiated for 10 min under NIR light (808 nm, 6 W cm-2). Besides, the Fe3+-TA complex exhibited ultralow cytotoxicity since only biocompatible tannic acid and iron ions were used as raw materials. Therefore, the merits of simple and convenient fabrication method, high photothermal conversion efficiency and excellent biocompatibility endow the high potential of Fe3+-TA complex as a photothermal agent for biomedical applications.

Preparation of Microkernel-Based Mesoporous (SiO2-CdTe-SiO2)@SiO2 Fluorescent Nanoparticles for Imaging Screening and Enrichment of Heat Shock Protein 90 Inhibitors from Tripterygium Wilfordii.

The currently utilized ligand fishing for bioactive molecular screening from complex matrixes cannot perform imaging screening. Here, we developed a new solid-phase ligand fishing coupled with an in situ imaging protocol for the specific enrichment and identification of heat shock protein 90 (Hsp 90) inhibitors from Tripterygium wilfordii, utilizing a multiple-layer and microkernel-based mesoporous nanostructure composed of a protective silica coating CdTe quantum dot (QD) core and a mesoporous silica shell, i.e., microkernel-based mesoporous (SiO2-CdTe-SiO2)@SiO2 fluorescent nanoparticles (MMFNPs) as extracting carries and fluorescent probes. The prepared MMFNPs showed a highly uniform spherical morphology, retention of fluorescence emission, and great chemical stability. The fished ligands by Hsp 90α-MMFNPs were evaluated via the preliminary bioactivity based on real-time cellular morphology imaging by confocal laser scanning microscopy (CLSM) and then identified by mass spectrometry (MS). Celastrol was successfully isolated as an Hsp 90 inhibitor, and two other specific components screened by Hsp 90α-MMFNPs, i.e., demecolcine and wilforine, were preliminarily identified as potential Hsp 90 inhibitors through the verification of strong affinity to Hsp 90 and antitumor bioactivity. The approach based on the MMFNPs provides a strong platform for imaging screening and discovery of plant-derived biologically active molecules with high efficiency and selectivity.

Liquid Exfoliation of Colloidal Rhenium Disulfide Nanosheets as a Multifunctional Theranostic Agent for In Vivo Photoacoustic/CT Imaging and Photothermal Therapy.

Near-infrared light-mediated theranostic agents with superior tissue penetration and minimal invasion have captivated researchers in cancer research in the past decade. Herein, a probe sonication-assisted liquid exfoliation approach for scalable and continual synthesis of colloidal rhenium disulfide nanosheets, which is further explored as theranostic agents for cancer diagnosis and therapy, is reported. Due to high-Z element of Re (Z = 75) and significant photoacoustic effect, the obtained PVP-capped ReS2 nanosheets are evaluated as bimodality contrast agents for computed tomography and photoacoustic imaging. In addition, utilizing the strong near-infrared absorption and ultrahigh photothermal conversion efficiency (79.2%), ReS2 nanosheets could also serve as therapeutic agents for photothermal ablation of tumors with a tumor elimination rate up to 100%. Importantly, ReS2 nanosheets show no obvious toxicity based on the cytotoxicity assay, serum biochemistry, and histological analysis. This work highlights the potentials of ReS2 nanosheets as a single-component theranostic nanoplatform for bioimaging and antitumor therapy.

Natural Humic-Acid-Based Phototheranostic Agent.

Humic acids, a major constituent of natural organic carbon resources, are naturally formed through the microbial biodegradation of animal and plant residues. Due to numerous physiologically active groups (phenol, carboxyl, and quinone), the biomedical applications of humic acid have been already investigated across different cultures for several centuries or even longer. In this work, sodium humate, the sodium salt of humic acid, is explored as phototheranostic agent for light-induced photoacoustic imaging and photothermal therapy based on intrinsic absorption in the near-infrared region. The purified colloidal sodium humate exhibits a high photothermal conversion efficiency up to 76.3%, much higher than that of the majority of state-of-the-art photothermal agents including gold nanorods, Cu9 S5 nanoparticles, antimonene quantum dots, and black phosphorus quantum dots, leading to obvious photoacoustic enhancement in vitro and in vivo. Besides, highly effective photothermal ablation of HeLa tumor is achieved through intratumoral injection. Impressively, sodium humate reveals ultralow toxicity at the cellular and animal levels. This work promises the great potential of humic acids as light-mediated theranostic agents, thus expanding the application scope of traditional humic acids in biomedical field.

Single-step, homogeneous and sensitive detection for microRNAs with dual-recognition steps based on luminescence resonance energy transfer (LRET) using upconversion nanoparticles.

A single-step, homogeneous and sensitive LRET assay is presented for the detection of miRNAs. The amplification-free assay provides a unique combination of high specificity with dual-recognition approach of different hybridization and ligation steps and preventing background auto-fluorescence in biological samples using upconversion nanoparticles (UCNPs) as signal-producing nanoprobes. The assay probe is composed of signal-producing unit (a pair of homogeneous upconversion luminescence resonance energy transfer (UC-LRET)-based oligonucleotides) and recognition unit (two adaptor oligonucleotides). In the presence of target miRNAs, the probe and target miRNAs leads to the formation of stable double-strands and semi-stable adaptor-miRNAs complexes with an adaptor nick. Ligation of the nick using ligase cause the formation of stable double-strands, resulting in UCNPs-to-dye UC-LRET for detection of the miRNAs with near-infrared radiation (980nm). Sensitive detection of miRNA-21 at concentrations of 200pM to 1.4nM and detection limits of 0.095nM with good precision of 3.9% (RSD) for seven repeated measurements of 500pM miRNAs demonstrate the feasibility of both high throughput and point-of-care clinical diagnostics. The homogeneous UC-LRET assay without any washing can be extended to the application in other important types of nucleic acid analysis.

Effects of bone marrow mesenchymal stem cell transplantation on voltage-gated K+channel proteins and cytokines in the infarcted myocardium of rats / 中国组织工程研究

BACKGROUND: Studies have shown that bone marrow mesenchymal stem cell (BMSC) transplantation can effectively improve cardiac function after myocardial infarction. However, few reports have been issued on myocardial electrophysiology after BMSCs transplantation. OBJECTIVE: To observe the effects of BMSCs transplantation on voltage-gated K+channel protein and myocardial infarction-related cytokines, thereby providing basic evidence for further exploration on the mechanism underlying arrhythmia in myocardial infarction due to BMSCs transplantation. METHODS: Forty male Wistar rats, SPF grade, were randomly divided into four groups: sham group, model group, cell culture medium group and BMSCs group. The myocardial infarction model was created in rats by permanent ligation of the left descending coronary artery. At 15-20 minutes after surgery, BMSCs (100 μL, 1×106) or cell culture medium (100 μL) was injected at four sites in the peri-infarct zone. Four weeks after cell therapy, cardiac samples were taken, the pathological morphology of the infarcted myocardium was observed by hematoxylin-eosin staining, and the infarct size was calculated; the expression levels of voltage-gated K+channel proteins Kv1.2 and Kv1.5 and cardiac troponin T (cTnT) were measured by western blot assay; and the expression levels of apoptotic factor (Caspase-3), autophagy factor (Bcl-2), nitric oxide and superoxide dismutase were tested by immunohistochemistry. RESULTS AND CONCLUSION: Compared with the model group and cell culture medium group, the infarct size decreased in the BMSCs group (P < 0.05); the expression levels of cTnT, Kv1.5 and superoxide dismutase increased (P < 0.05), and the expression levels of Caspase-3, Bcl-2 and Kv1.2 decreased (P < 0.05) in the BMSCs group. In summary, BMSCs transplantation can promote the expression of voltage-gated K+channel proteins, and improve anti-oxidation capacity of the myocardium and decrease apoptosis and autophagy.