Sodium-glucose cotransporter 2 inhibitors’ mechanisms of action in heart failure

Three major cardiovascular outcome trials(CVOTs)with a new class of antidiabetic drugs-sodium-glucose cotransporter 2(SGLT2)inhibitors(EMPAREG OUTCOME trial with empagliflozin,CANVAS Program with canagliflozin,DECLARE-TIMI 58 with dapagliflozin)unexpectedly showed that cardiovascular outcomes could be improved possibly due to a reduction in heart failure risk,which seems to be the most sensitive outcome of SGLT2 inhibition.No other CVOT to date has shown any significant benefit on heart failure events.Even more impressive findings came recently from the DAPA-HF trial in patients with confirmed and well-treated heart failure:Dapagliflozin was shown to reduce heart failure risk for patients with heart failure with reduced ejection fraction regardless of diabetes status.Nevertheless,despite their possible wide clinical implications,there is much doubt about the mechanisms of action and a lot of questions to unravel,especially now when their benefits translated to nondiabetic patients,rising doubts about the validity of some current mechanistic assumptions.The time frame of their cardiovascular benefits excludes glucoselowering and antiatherosclerotic-mediated effects and multiple other mechanisms,direct cardiac as well as systemic,are suggested to explain their early cardiorenal benefits.These are:Anti-inflammatory,antifibrotic,antioxidative,antiapoptotic properties,then renoprotective and hemodynamic effects,attenuation of glucotoxicity,reduction of uric acid levels and epicardial adipose tissue,modification of neurohumoral system and cardiac fuel energetics,sodiumhydrogen exchange inhibition.The most logic explanation seems that SGLT2 inhibitors timely target various mechanisms underpinning heart failure pathogenesis.All the proposed mechanisms of their action could interfere with evolution of heart failure and are discussed separately within the main text.

Ipragliflozin: A novel sodium-glucose cotransporter 2 inhibitor developed in Japan

Sodium-glucose cotransporter 2(SGLT2) inhibition induces glucosuria and decreases blood glucose levels in diabetic patients and lowers hypoglycemic risk. SGLT1 is expressed in the kidney and intestine; SGLT1 inhibition causes abdominal symptoms such as diarrhea and reduces incretin secretion. Therefore, SGLT2 selectivity is important. Ipragliflozin is highly selective for SGLT2. In type 2 diabetes mellitus(T2DM), urinaryglucose excretion increased to 90 g/24 h after 28 d of treatment with ipragliflozin 300 mg/d. Twelve weeks of ipragliflozin 50 mg/d vs placebo reduced glycated hemoglobin and body weight by 0.65% and 0.66 kg, respectively, in Western T2 DM patients, and by 1.3% and 1.89 kg, respectively, in Japanese patients. Ipragliflozin(highly selective SGLT2 inhibitor) improves glycemic control and reduces body weight and lowers hypoglycemic risk and abdominal symptoms. Ipragliflozin can be a novel anti-diabetic and antiobesity agent.

Potential for sodium-glucose cotransporter-2 inhibitors in the management of metabolic syndrome: A systematic review and metaanalysis

BACKGROUND Landmark trials have established the benefits of sodium-glucose cotransporter-2 inhibitors(SGLT2-Is)in cardiovascular disease including heart failure with reduced and preserved ejection fraction and renal diseases regardless of the presence of diabetes mellitus.However,studies evaluating the role of SGLT2-Is in metabolic syndrome(MetS)are limited.AIM This study primarily aimed to evaluate the impact of SGLT2-Is on the components of MetS.METHODS Two independent reviewers and an experienced librarian searched Medline,Scopus and the Cochrane central from inception to December 9,2021 to identify placebo controlled randomized controlled trials that evaluated the impact of SGLT2-Is on the components of MetS as an endpoint.Pre-and post-treatment data of each component were obtained.A meta-analysis was performed using the RevMan(version 5.3;Copenhagen:The Nordic Cochrane Center,The Cochrane Collaboration).RESULTS Treatment with SGLT2-Is resulted in a decrease in fasting plasma glucose(–18.07 mg/dL;95%CI:-25.32 to–10.82),systolic blood pressure(–1.37 mmHg;95%CI:-2.08 to–0.65),and waist circumference(–1.28 cm;95%CI:-1.39 to–1.18)compared to placebo.The impact on highdensity lipoprotein cholesterol was similar to placebo(0.01 mg/dL;95%CI:-0.05 to 0.07).CONCLUSION SGLT2-Is have a promising role in the management of MetS.

Mechanism Underlying Increase of the Serum Magnesium Concentration Observed Following Treatment with Sodium-Glucose Cotransporter 2 Inhibitors

Aim: The EMPA-REG OUTCOME study reported that the sodium-glucose cotransporter 2 inhibitor (SGLT2-i) suppressed cardiovascular (CV) events in patients with type 2 diabetes;we recently suggested that increase of the serum magnesium (Mg) by SGLT2-i’s can, in part, explain this reduction. The objective of this study was to elucidate the mechanism underlying the elevation of the serum Mg level induced by treatment with SGLT2-i’s. Methods: We analyzed the data of 37 patients with type 2 diabetes who underwent clinical evaluation and laboratory assessment at baseline and the end of 3 months. To investigate the relationship between the changes in the serum Mg concentrations during 3 months’ treatment (ΔMg) and other variables, we carried out simple linear regression analysis and multiple linear regression analysis. Results: Three months’ treatment with the SGLT2-i resulted in a significant improvement of the body weight (BW), BMI, hemoglobin A1c (HbA1c), and fasting plasma glucose levels. The serum Mg increased significantly. Simple linear regression analysis revealed an association between the ΔMg and the serum triglyceride, serum Mg at baseline, change of the BW (ΔBW), and change of the HbA1c. Multiple linear regression analysis revealed a significant association between the ΔMg and the serum Mg level at the baseline (r = -0.55, P Conclusion: Our study revealed that a lower serum Mg level at the baseline and BW reduction were significantly associated with an increase in the serum Mg following 3 months’ treatment with SGLT2-i’s.

Chances and risks of sodium-glucose cotransporter 2 inhibitors in solid organ transplantation:A review of literatures

Solid organ transplantation offers life-saving treatment for patients with endorgan dysfunction.Patient survival and quality of life have improved over the past few decades as a result of pharmacological development,expansion of the donor pool,technological advances and standardization of practices related to transplantation.Still,transplantation is associated with cardiovascular complications,of which post-transplant diabetes mellitus(PTDM)is one of the most important.PTDM increases mortality,which is best documented in patients who have received kidney and heart transplants.PTDM results from traditional risk factors seen in patients with type 2 diabetes mellitus,but also from specific posttransplant risk factors such as metabolic side effects of immunosuppressive drugs,post-transplant viral infections and hypomagnesemia.Oral hypoglycaemic agents are the first choice for the treatment of type 2 diabetes mellitus in non-transplanted patients.However,the evidence on the safety and efficacy of oral hypoglycaemic agents in transplant recipients is limited.The favourable risk/benefit ratio,which is suggested by large-scale and long-term studies on new glucoselowering drug classes such as glucagon-like peptide 1 receptor agonists and sodium-glucose cotransporter 2 inhibitors,makes studies warranted to assess the potential role of these agents in the management of PTDM.

Antihypertensive Effect of Sodium-Glucose Cotransporter 2 Inhibitors and Glucagon-like Peptide 1 Receptor Agonists

An increasing body of evidence shows that new antidiabetic drugs—particularly sodium-glucose cotransporter 2(SGLT2)inhibitors and glucagon-like peptide 1(GLP-1)receptor agonists—have a beneficial effect on cardiovascular outcome.The majority of these studies have been performed in patients with heart failure and the results have shown first positive effect on blood pressure(BP)reduction.These effects are more pronounced with SGLT2 inhibitors than with GLP-1 receptor agonists.However,the reasons and mechanisms of action inducing BP reduction are still not sufficiently clear.Proposed mechanisms of SGLT2 inhibitors involve the natriuretic effect,modification of the renin-angiotensin-aldosterone system,and/or the reduction in the sympathetic nervous system.GLP-1 receptor agonists have several mechanisms that are related to glycemic,weight,and BP control.Current data show that SGLT2 inhibitors have a stronger antihypertensive effect than GLP-1 receptor agonists,which is mainly related to their renal effect.Briefly,SGLT2 inhibitors increase the response to diuretics and decrease the meal-related antinatriuretic pressure by lowering post-prandial hyperglycemia and hyperinsulinemia and prevent proximal sodium reabsorption.SGLT2 inhibitors can be used as second-line therapy in patients with diabetes mellitus or heart disease and concomitant hypertension.This article aims to summarize current knowledge regarding the antihypertensive effect of SGLT2 inhibitors and GLP-1 receptor agonists.

Sodium-glucose co-transporter-2 inhibitor-associated euglycemic diabetic ketoacidosis that prompted the diagnosis of fulminant type-1 diabetes:A case report

Fulminant type 1 diabetes mellitus(FT1DM)is a subtype of type 1 diabetes mellitus characterized by an abrupt onset and a rapid and complete functional loss of isletβcells.It is a very rare disease generally associated with ketoacidosis and the absence of circulating pancreatic islet-related autoantibodies.Diabetic ketoacidosis with normal blood glucose levels has been reported during sodiumglucose co-transporter 2(SGLT2)inhibitor therapy.CASE SUMMARY The patient was a 43-year-old woman that consulted a medical practitioner for malaise,thirst,and vomiting.Blood analysis showed high blood glucose levels(428 mg/dL),a mild increase of hemoglobin A1c(6.6%),and increased ketone bodies in urine.The patient was diagnosed with type 2 diabetes mellitus.The patient was initially treated with insulin,which was subsequently changed to an oral SGLT2 inhibitor.Antibodies to glutamic acid decarboxylase were negative.Four days after receiving oral SGLT2 inhibitor,she consulted at Mie University Hospital,complaining of fatigue and vomiting.Laboratory analysis revealed diabetic ketoacidosis with almost normal blood glucose levels.The endogenous insulin secretion was markedly low,and the serum levels of islet-related autoantibodies were undetectable.We made the diagnosis of FT1DM with concurrent SGLT2 inhibitor-associated euglycemic diabetic ketoacidosis.The patient's general condition improved after therapy with intravenous insulin and withdrawal of oral medication.She was discharged on day 14 with an indication of multiple daily insulin therapy.CONCLUSION This patient is a rare case of FT1DM that developed SGLT2 inhibitor-associated diabetic ketoacidosis with almost normal blood glucose levels.This case report underscores the importance of considering the diagnosis of FT1DM in patients with negative circulating autoantibodies and a history of hyperglycemia that subsequently develop euglycemic diabetic ketoacidosis following treatment with a SGLT2 inhibitor.

Role of the Na^+/K^+/2Cl^- cotransporter NKCC1 in cell cycle progression in human esophageal squamous cell carcinoma

AIM:To investigate the role of Na+/K+/2Cl-cotransporter 1(NKCC1)in the regulation of genes involved in cell cycle progression and the clinicopathological significance of its expression in esophageal squamous cell carcinoma(ESCC).METHODS:An immunohistochemical analysis was performed on 68 primary tumor samples obtained from ESCC patients that underwent esophagectomy.NKCC1expression in human ESCC cell lines was analyzed by Western blotting.Knockdown experiments were conducted using NKCC1 small interfering RNA,and the effects on cell cycle progression were analyzed.The gene expression profiles of cells were analyzed by microarray analysis.RESULTS:Immunohistochemical staining showed that NKCC1 was primarily found in the cytoplasm of carcinoma cells and that its expression was related to the histological degree of differentiation of SCC.NKCC1 was highly expressed in KYSE170 cells.Depletion of NKCC1in these cells inhibited cell proliferation via G2/M phase arrest.Microarray analysis identified 2527 genes with altered expression levels in NKCC1depleted KYSE170.Pathway analysis showed that the top-ranked canonical pathway was the G2/M DNA damage checkpoint regulation pathway,which involves MAD2L1,DTL,BLM,CDC20,BRCA1,and E2F5.CONCLUSION:These results suggest that the expression of NKCC1 in ESCC may affect the G2/M checkpoint and may be related to the degree of histological differentiation of SCCs.We have provided a deeper understanding of the role of NKCC1 as a mediator and/or a biomarker in ESCC.

Expression and Purification of Hydrophilic Domains of Bovine Anion Exchanger,Member 1 and Electrogenic Sodium Bicarbonate Cotransporter 1

[ Objective] To express and purify the intracellular hydrophilic domains of bovine membrane carrier proteins：anion exchanger, member 1 （AE1） and electregenic sodium bicarbonate cotransporter 1 （NBCel）, which were associated with bicarbonate ion transport. [ Method] The hydrophilic domains of bovine AE1 and NBCel were amplified by PCR and inserted into the prokaryotic expression vector pET-28a, respectively. The recombinant plasmids were transformed into the expression strain E. coli BL21 （DE3） and then induced by IPTG. The expressed proteins were purified by nickel ion affinity chromatography and analyzed by 15% SDS-PAGE. [Result] The hydrophilic domains of bovine AE1 and NBCel were amplified respectively by PCR and expressed by prokaryotic expression system with the induction of IPTG. They were mainly expressed in the cyto- plasm of E. coli and high-purity was achieved by nickel ion affinity chromatography. [Condusion] The expression of the hydrophilic domains of bovine AE1 and NBCel provides a major exit route for preparation of antibodies and the regulatory mechanisms of carrier proteins.

Update on evidence-based clinical application of sodium-glucose cotransporter inhibitors:Insight to uncommon cardiovascular disease scenarios in diabetes

In this paper,we concentrate on updating the clinical research on sodium-glucose cotransporter inhibitors(SGLTis)for patients with type 2 diabetes who have heart failure with a preserved injection fraction,acute heart failure,atrial fibrillation,primary prevention of atherosclerotic cardiovascular disease/cardiovascular disease,and acute myocardial infarction.We searched the data of randomized controlled trials and meta-analyses of SGLTis in patients with diabetes from PubMed between January 1,2020 and April 6,2024 for our review.According to our review,certain SGLTis(empagliflozin,dapagliflozin,canagliflozin,and tofogliflozin),but not sodium-glucose cotransporter 1 inhibitor(SGLT1i),exhibit relatively superior clinical safety and effectiveness for treating the abovementioned diseases.Proper utilization of SGLTis in these patients can foster clinical improvement and offer an alternative medication option.However,clinical trials involving SGLTis for certain diseases have relatively small sample sizes,brief intervention durations,and conclusions based on weak evidence,necessitating additional data.These findings are significant and valuable for providing a more comprehensive reference and new possibilities for the clinical utilization and scientific exploration of SGLTis.

Role of the cation-chloride-cotransporters in the circadian system

The circadian system plays an immense role in controlling physiological processes in our body.The suprachiasmatic nucleus (SCN) supervises this system,regulating and harmonising the circadian rhythms in our body.Most neurons present in the SCN are GABAergic neurons.Although GABA is considered the main inhibitory neurotransmitter of the CNS,recent studies have shown that excitatory responses were recorded in this area.These responses are enabled by an increase in intracellular chloride ions[Cl;];levels.The chloride (Cl;) levels in GABAergic neurons are controlled by two solute carrier 12 (SLC12)cation-chloride-cotransporters (CCCs):Na^(+)/K^(+)/Cl^(-)co-transporter (NKCC1) and K^(+)/Cl^(-)cotransporter (KCC2),that respectively cause an influx and efflux of Cl^(-).Recent works have found altered expression and/or activity of either of these co-transporters in SCN neurons and have been associated with circadian rhythms.In this review,we summarize and discuss the role of CCCs in circadian rhythms,and highlight these recent advances which attest to CCC’s growing potential as strong research and therapeutic targets.

钠-葡萄糖协同转运蛋白2抑制剂对沉默信息调节因子1信号通路的调控作用及其在糖尿病肾病中发挥肾脏保护作用的机制研究进展

糖尿病肾病(DN)是糖尿病主要并发症之一,是导致终末期肾病的主要原因。钠-葡萄糖协同转运蛋白2(SGLT2)抑制剂是一种新型降糖药物,与其他降糖药物相比,SGLT2抑制剂的降糖优势并不明显,但其肾脏保护作用却很突出。SGLT2抑制剂可以激活沉默信息调节因子1(SIRT1)信号通路促进肾脏细胞自噬,降低氧化应激,改善肾脏缺氧从而保护肾脏,延缓糖尿病肾病进展。SGLT2抑制剂发挥肾脏保护作用的机制可能与其对SIRT1信号通路的影响有关。本文对SGLT2抑制剂通过调控SIRT1发挥肾脏保护作用的研究进展进行综述,旨在总结SGLT2抑制剂对糖尿病肾脏保护作用的机制。

Na^+/HCO_3^- cotransporter is expressed on β and α cells during rat pancreatic development

AIM To determine the expression and localization of the electrogenic Na^+/HCO_3^- cotransporter(NBC1) in rat pancreas during development. METHODS The rat pancreas from postnatal and embryos removed from the uterus of pregnant rats that had been sacrificed by CO2 asphyxiation were used. Rat pancreas from embryonic day(E) 15.5 and E18.5 rat embryos was isolated under a stereomicroscope. Rat pancreas from postnatal(P) days 0, 7, 14, 21 and adult was directly isolated by the unaided eye. The RT-PCR analysis of the NBC1 specific region on rat pancreastissues from different developmental stages. The two antibodies which target the NBC1 common COOHterminal region and NH2-terminal region detected a clear band of about 145 k Da in the Western blot analysis. The localization of NBC1 was examined by immuno-fluorescence detection. RESULTS The results revealed the first peak of NBC1 expression at E18.5 and the second peak at P14. Meanwhile, the low NBC1 expression occurred at P7 and adult stages. Our results demonstrated, for the first time, the presence of NBC1 in the plasma membrane of β and α cells, as well as in the basolateral membrane of acinar cells of the rat pancreas at different stages of development. CONCLUSION The data strongly suggests that NBC1 is diversely expressed in the pancreas at different developmental stages, where it may exert its functions in pancreatic development especially islet cell growth through HCO_3^- transport and pH regulation.

钠-葡萄糖共转运蛋白-2抑制剂联合胰高血糖素样肽-1受体激动剂治疗超重/肥胖2型糖尿病患者的研究进展

钠-葡萄糖共转运蛋白-2抑制剂(SGLT-2i)和胰高血糖素样肽-1受体激动剂(GLP-1RA)是近年来降糖药物的热点研究方向。随着临床的广泛应用,SGLT2抑制剂及GLP-1受体激动剂已不限于用来治疗2型糖尿病(T2DM)的患者血糖,还能从减重、降脂、保护心脏等多个方面间接或直接地改善超重/肥胖2型糖尿病患者的血脂、体重及降低心血管事件发生风险。然而,由于超重/肥胖2型糖尿病的发病机制尚未明确,目前临床关于超重/肥胖2型糖尿病缺少彻底有效的治疗方案,主要为使用传统的不增加体重的降糖药,不能达到良好的治疗效果。因此,本文总结了SGLT2抑制剂及GLP-1受体激动剂降糖减重、调脂、保护心脏的机制及两者联合使用对超重/肥胖2型糖尿病患者的作用效果及安全性,为临床提供可靠的用药参考。

木聚糖酶对尼罗罗非鱼钠葡萄糖共转运载体(SGLT_1)mRNA表达的影响

以尼罗罗非鱼[体重(106.16±16.77)g]为实验对象,小麦基础饲料为对照,小麦基础饲料中分别添加不同水平的木聚糖酶(0.05%、0.10%、0.15%)作为试验饲料。每个处理设5个重复,每个重复放养40尾雄性尼罗罗非鱼,旨在研究木聚糖酶对尼罗罗非鱼前肠和中肠钠葡萄糖共转运载体(SGLT_1)mRNA表达的影响,从分子水平揭示木聚糖酶促进尼罗罗非鱼生长的机理。饱食投喂,饲养75 d后,每饲料组分别取10尾鱼,尾静脉取血制备血清,测定血糖含量;采用离心柱型总RNA提取试剂金提取前肠和中肠总RNA,通过RT-PCR对前肠和中肠SGLT_1mRNA的表达进行相对定量。结果表明,0.05%组、0.10%组和0.15%组前肠SGLT_1 mRNA的相对表达量分别比对照组提高19.28%(P<0.05)、42.17%(P<0.01)和16.87% (P<0.05);对照组尼罗罗非鱼在摄食后2 h血糖仅为5.56 mmol·L^(-1),0.10%组极显著高于对照组(P<0.01);0.05%组和0.10%组的增重率较对照组分别提高8.29%、17.45%(P<0.01),0.15%组的增重率与对照组相比没有统计学差异(P>0.05)。研究结果表明,在小麦基础饲料中适量添加木聚糖酶能显著上调前肠SGLT_1mRNA的表达,促进葡萄糖吸收,从而提高尼罗罗非鱼的生长速度。

基于水协同转运蛋白KCC1、KCC3、KCC4、NKCC1含量及Na^+ -K^+ -ATP酶活性变化研究湿阻中焦证的水液代谢机制

目的：以前期研究的水通道蛋白为平台,通过观察并分析水协同转运蛋白KCC1、KCC3、KCC4、NKCC1含量及Na~＋-K~＋-ATP酶活性变化,揭示湿阻中焦致水液代谢紊乱及平胃散对其修复作用机制的科学内涵,为中医临床治疗本证型疾病提供实验参考;同时搭建中药复方水通道调节剂的研究平台。方法：模拟＂外湿过盛,困阻脾胃、饮食不节,湿从内生、情志不遂,气机受阻、水湿不运三大致湿病因,建立湿阻中焦证模型。用蛋白定量法测定Na~＋-K~＋-ATP酶活性,用酶联免疫法（ELISA）测定肾脏组织KCC1,KCC3,KCC4,NKCC1的含量。结果：与空白组比较,模型组肾脏KCC1、KCC4含量升高,KCC3、NKCC1、Na~＋-K~＋-ATP酶活力降低,与模型组比较,自然恢复组肾脏KCC1、KCC3、NKCC1含量降低,Na~＋-K~＋-ATP酶活力明显升高（P〈0.01）,KCC4含量有上升趋势,经药物干预后,各给药组KCC1含量均明显降低（P〈0.01）,平胃散中剂量组KCC3、KCC4含量明显升高（P〈0.01）,平胃散低剂量组NKCC1含量明显降低（P〈0.01）;平胃散低剂量组肾脏Na~＋-K~＋-ATP酶活力明显升高（P〈0.01）;呋塞米组和平胃散加泽泻组KCC1、KCC3、KCC4、NKCC1含量及Na~＋-K~＋-ATP酶活性均明显降低,差异有统计学意义（P〈0.01）;与自然恢复组比较,平胃散中剂量组肾脏KCC1、KCC3、KCC4含量及Na~＋-K~＋-ATP酶活力有上升趋势,平胃散低剂量组NKCC1含量下降明显（P〈0.01）,呋塞米组和平胃散加泽泻组KCC1、KCC3、KCC4、NKCC1含量及Na~＋-K~＋-ATP酶活性均明显降低,差异有统计学意义（P〈0.01）。结论：（1）湿阻中焦证模型不仅能够影响体内能量代谢,还能够影响KCC1、KCC3、KCC4、NKCC1含量表达,这可能是湿阻中焦导致水代谢输布障碍的机制之一;（2）平胃散能够调整Na~＋-K~＋-ATP酶活性和KCC1、KCC3、KCC4、NKCC1含量分布参与能量代谢和水液代谢调控,这可能是平胃散燥湿运脾、行气导滞、散中焦之湿阻治疗湿阻中焦证的分子机理之一;（3）水协同转运蛋白之间可能存在互补代偿机制。

鲤肠道sglt1基因的表达与抗体制备

钠/葡萄糖共转运载体1(sodium/glucose cotransporter 1,Sglt1)是协助葡萄糖吸收的主要蛋白。实验首先采用RT-PCR获取sglt1基因全长,克隆至PGME-T载体进行序列及免疫原性分析,选择长度为92个氨基酸(544～637)的多肽作为目的片段(sglt1-P)),扩增sglt1-P,引入双酶切位点EcoRⅠ和HindⅢ后,连接至pET-32a(+)上,构建表达载体pET-32a(+)-sglt1-P,转化至E.coli Rosetta中,获得重组基因工程菌,通过IPTG诱导表达,获得目标多肽,并以此为抗原制备Sglt1特异性抗体。SDS-PAGE电泳分析表明,目标多肽分子量约为30 ku。采用耳缘静脉结合皮下注射,免疫新西兰长耳兔,免疫总时长为38 d。制备了鲤Sglt1抗体,ELISA测得效价为1∶105;免疫组化结果表明,抗体具有较高亲和力和特异性,可以应用于鲤Sglt1的表达定位研究。该抗体的获得为鲤肠道Sglt1表达及转运活性的系统研究奠定了基础,同时,获取的Sglt1抗体亦可用于其它鱼类Sglt1转运蛋白表达定位和定量研究。

C57BL/6J小鼠耳蜗血管纹Na-K-2Cl联合转运子-1的年龄相关性变化

目的观察不同周龄C57BL/6J(C57)小鼠听力及血管纹Na-K-2Cl联合转运子-1(Na-K-2Cl co-transporter-1,NKCC1)表达的情况。方法应用听性脑干反应(auditory brainstemresponse,ABR)分别检测4、8、16、32、48、64周龄组C57小鼠的听力;采用免疫组织化学染色法观察其血管纹NKCC1表达的变化。结果C57小鼠随年龄增大出现听力下降,自16周龄时ABR阈值出现显著性增高(P<0.05);血管纹NKCC1表达也出现年龄相关性减少,其灰度值自16周龄时显著增高(P<0.01)。结论C57小鼠血管纹NKCC1蛋白表达随年龄增长而减少,可能与年龄相关性听力损失具有一定相关性。

鞘内注射布美他尼对大鼠急性疼痛行为及钠钾氯联合转运蛋白1表达的影响

目的探讨鞘内注射布美他尼对大鼠术后痛觉过敏形成的作用机制,为临床研究及应用提供理论参考。方法采用随机数字表法将大鼠分为对照组、注药组、手术组及实验组。采用热辐射法(热痛敏)、von Frey细丝法(机械痛敏)及疼痛累计评分法(疼痛保护反应)观察、记录术前及术后2、4、6 h大鼠的行为学改变,采用免疫组化,荧光显微镜观察各组术后2、4、6 h背根神经节(DRG)的NKCC1表达,并行阳性细胞计数。结果手术组与实验组术后各时间点的热痛阈均降低(P<0.05);实验组热痛阈明显高于手术组(P<0.05)。注药组大鼠在注药后2 h的机械痛阈升高(P<0.05),手术组大鼠的机械痛阈明显低于实验组(P<0.05)。手术组与实验组术后疼痛累计评分均升高(P<0.05),但手术组明显高于实验组(P<0.05)。手术组及实验组在各时间点阳性细胞计数均明显增多(P<0.01);组间比较,实验组的阳性细胞计数明显少于手术组(P<0.01)。结论鞘内注射布美他尼能提高切口痛模型大鼠的热痛阈值及机械痛阈值,降低疼痛累计评分,减少切口痛模型大鼠DRG的NKCC1的表达,提示布美他尼对急性疼痛过敏的形成有抑制作用,其抗伤害作用可能与抑制NKCC1活动有关。NKCC1对急性痛觉过敏形成与维持起重要作用。

抑制NKCC1减轻小鼠创伤性脑损伤的研究

目的探讨钠-钾-氯共转运体1(Na+-K+-2Cl-cotransporter 1,NKCC1)抑制剂布美他尼处理(BT)对小鼠创伤性脑损伤(TBI)早期的脑保护作用及可能分子信号调控机制。方法成年雄性BALB/c小鼠54只,随机分为对照组,颅脑创伤组(TBI组)和布美他尼治疗组(BTT组)各18只,采用Mamarou加速性颅脑损伤方法制备小鼠TBI模型。采用HE染色法观察各组小鼠皮层损伤程度;利用神经功能学评分(NSS)进行神经功能学评分;干湿重法检测脑组织含水量;同时,Western blot法检测磷酸化细胞外调节蛋白激酶(p-ERK)、细胞外调节蛋白激酶(ERK)蛋白的表达变化。结果与TBI组比较,BTT组皮层神经元损伤减轻,同时,BTT组小鼠神经功能学评分优于TBI组(P<0.05);TBI后12 h,BTT组p-ERK的蛋白表达水平低于TBI组(P<0.01)。结论抑制NKCC1的表达可能发挥重要的脑保护作用,而p-ERK可能参与NKCC1的信号调控机制。