Cell metabolism pathways involved in the pathophysiological changes of diabetic peripheral neuropathy

Diabetic peripheral neuropathy is a common complication of diabetes mellitus.Elucidating the pathophysiological metabolic mechanism impels the generation of ideal therapies.However,existing limited treatments for diabetic peripheral neuropathy expose the urgent need for cell metabolism research.Given the lack of comprehensive understanding of energy metabolism changes and related signaling pathways in diabetic peripheral neuropathy,it is essential to explore energy changes and metabolic changes in diabetic peripheral neuropathy to develop suitable treatment methods.This review summarizes the pathophysiological mechanism of diabetic peripheral neuropathy from the perspective of cellular metabolism and the specific interventions for different metabolic pathways to develop effective treatment methods.Various metabolic mechanisms(e.g.,polyol,hexosamine,protein kinase C pathway)are associated with diabetic peripheral neuropathy,and researchers are looking for more effective treatments through these pathways.

Secreted Frizzled-Related Protein 5 Mediates Wnt5a Expression in Microcystin-Leucine-Arginine-Induced Liver Lipid Metabolism Disorder in Mice

Objective Microcystin-leucine-arginine(MC-LR)exposure induces lipid metabolism disorders in the liver.Secreted frizzled-related protein 5(SFRP5)is a natural antagonist of winglesstype MMTV integration site family,member 5A(Wnt5a)and an anti-inflammatory adipocytokine.In this study,we aimed to investigate whether MC-LR can induce lipid metabolism disorders in hepatocytes and whether SFRP5,which has anti-inflammatory effects,can alleviate the effects of hepatic lipid metabolism by inhibiting the Wnt5a/Jun N-terminal kinase(JNK)pathway.Methods We exposed mice to MC-LR in vivo to induce liver lipid metabolism disorders.Subsequently,mouse hepatocytes that overexpressed SFRP5 or did not express SFRP5 were exposed to MC-LR,and the effects of SFRP5 overexpression on inflammation and Wnt5a/JNK activation by MC-LR were observed.Results MC-LR exposure induced liver lipid metabolism disorders in mice and significantly decreased SFRP5 mRNA and protein levels in a concentration-dependent manner.SFRP5 overexpression in AML12cells suppressed MC-LR-induced inflammation.Overexpression of SFRP5 also inhibited Wnt5a and phosphorylation of JNK.Conclusion MC-LR can induce lipid metabolism disorders in mice,and SFRP5 can attenuate lipid metabolism disorders in the mouse liver by inhibiting Wnt5a/JNK signaling.

Targeted metabolomics reveals the aberrant energy status in diabetic peripheral neuropathy and the neuroprotective mechanism of traditional Chinese medicine JinMaiTong

Diabetic peripheral neuropathy (DPN) is a common and devastating complication of diabetes, for which effective therapies are currently lacking. Disturbed energy status plays a crucial role in DPN pathogenesis. However, the integrated profile of energy metabolism, especially the central carbohydrate metabolism, remains unclear in DPN. Here, we developed a metabolomics approach by targeting 56 metabolites using high-performance ion chromatography-tandem mass spectrometry (HPIC-MS/MS) to illustrate the integrative characteristics of central carbohydrate metabolism in patients with DPN and streptozotocin-induced DPN rats. Furthermore, JinMaiTong (JMT), a traditional Chinese medicine (TCM) formula, was found to be effective for DPN, improving the peripheral neurological function and alleviating the neuropathology of DPN rats even after demyelination and axonal degeneration. JMT ameliorated DPN by regulating the aberrant energy balance and mitochondrial functions, including excessive glycolysis restoration, tricarboxylic acid cycle improvement, and increased adenosine triphosphate (ATP) generation. Bioenergetic profile was aberrant in cultured rat Schwann cells under high-glucose conditions, which was remarkably corrected by JMT treatment. In-vivo and in-vitro studies revealed that these effects of JMT were mainly attributed to the activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) and downstream peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). Our results expand the therapeutic framework for DPN and suggest the integrative modulation of energy metabolism using TCMs, such as JMT, as an effective strategy for its treatment.

AB015.Metabolic stress in glaucoma engages early activation of the energy biosensor adenosine monophosphate-activated protein kinase leading to neuronal dysfunction

Background:Metabolic stress has been proposed to contribute to neuronal damage in glaucoma,but the mechanism driving this response is not understood.The adenosine monophosphate-activated protein kinase(AMPK)is a master regulator of energy homeostasis that becomes active at the onset of energy stress.AMPK is a potent inhibitor of the mammalian target of rapamycin complex 1(mTORC1),which we showed is essential for the maintenance of retinal ganglion cell(RGC)dendrites,synapses,and survival.Here,we tested the hypothesis that AMPK is an early mediator of metabolic stress in glaucoma.Methods:Unilateral elevation of intraocular pressure was induced by injection of magnetic microbeads into the anterior chamber of mice expressing yellow fluorescent protein in RGCs.Inhibition of AMPK was achieved by administration of siRNA or compound C.RGC dendritic trees were 3D-reconstructed and analyzed with Imaris(Bitplane),and survival was assessed by counting Brn3a or RBPMS-labeled soma and axons in the optic nerve.RGC function was examined by quantification of anterograde axonal transport after intraocular administration of cholera toxinβ-subunit.Retinas from glaucoma patients were analyzed for expression of active AMPK.Results:Ocular hypertension triggered rapid upregulation of AMPK activity in RGCs concomitant with loss of mTORC1 function.AMPK inhibition with compound C or siRNA effectively restored mTORC1 activity and promoted an increase in total dendritic length,surface and complexity relative to control retinas.Attenuation of AMPK activity led to robust RGC soma and axon survival.For example,95%of RGCs(2,983±258 RGCs/mm2,mean±S.E.M.)survived with compound C compared to 77%in vehicle-treated eyes(2,430±233 RGCs/mm2)(ANOVA,P<0.001)at three weeks after glaucoma induction(n=8-10/group).Importantly,blockade of AMPK activity effectively restored anterograde axonal transport.Lastly,RGC-specific upregulation of AMPK activity was detected in human glaucomatous retinas relative to age-matched controls(n=10/group).Conclusions:Metabolic stress in glaucoma involves AMPK activation and mTORC1 inhibition promoting early RGC dendritic pathology,dysfunction and neurodegeneration.

Bombyx mori Pyridoxal Kinase cDNA Cloning and Enzymatic Characterization

Pyridoxal kinase （PLK） （EC 2.7.1.35） catalyzes the ATP-dependent phosphorylation of pyridoxal, generating pyridoxal-5＇-phosphate （PLP）, an important cofactor for many enzymatic reactions. Bombyx mori, similar to mammals, relies on a nutritional source of vitamin B6 to synthesize PLP. This article describes how a cDNA encoding PLK was cloned from Bombyx mori using the PCR method （GenBank accession number： DQ452397）. The cDNA has an 894 bp open reading frame and encodes a protein of 298 amino acid residues with a molecular mass of 33.1 k.Da. The amino acid sequence shares 48.6% identity with that of human PLK, and it also contains signature conserved motifs of the PLK family. However, the protein is 10 or more amino acids shorter than the PLK from mammals and plants, and several amino acid residues conserved in the PLK from mammals and plants are changed in the protein. The cDNA cloned was expressed successfully in Escherichia coli using the T7 promoter/T7 RNA polymerase expression system, and the crude extracts containing the expressed product were found to have strong PLK enzymatic activity with a value of 30 nmol/min/mg, confirming that the cDNA encodes the functional PLK of Bombyx mori. This is the first identification of a gene encoding PLK in insects.

Multiomics analysis reveals metabolic subtypes and identifies diacylglycerol kinase α (DGKA) as a potential therapeutic target for intrahepatic cholangiocarcinoma

Background:Intrahepatic cholangiocarcinoma(iCCA)is a highly heteroge-neous and lethal hepatobiliary tumor with few therapeutic strategies.The metabolic reprogramming of tumor cells plays an essential role in the develop-ment of tumors,while the metabolic molecular classification of iCCA is largely unknown.Here,we performed an integrated multiomics analysis and metabolic classification to depict differences in metabolic characteristics of iCCA patients,hoping to provide a novel perspective to understand and treat iCCA.Methods:We performed integrated multiomics analysis in 116 iCCA samples,including whole-exome sequencing,bulk RNA-sequencing and proteome anal-ysis.Based on the non-negative matrix factorization method and the protein abundance of metabolic genes in human genome-scale metabolic models,the metabolic subtype of iCCA was determined.Survival and prognostic gene analy-ses were used to compare overall survival(OS)differences between metabolic subtypes.Cell proliferation analysis,5-ethynyl-2’-deoxyuridine(EdU)assay,colony formation assay,RNA-sequencing and Western blotting were performed to investigate the molecular mechanisms of diacylglycerol kinaseα(DGKA)in iCCA cells.Results:Three metabolic subtypes(S1-S3)with subtype-specific biomarkers of iCCA were identified.These metabolic subtypes presented with distinct prog-noses,metabolic features,immune microenvironments,and genetic alterations.The S2 subtype with the worst survival showed the activation of some special metabolic processes,immune-suppressed microenvironment and Kirsten ratsar-coma viral oncogene homolog(KRAS)/AT-rich interactive domain 1A(ARID1A)mutations.Among the S2 subtype-specific upregulated proteins,DGKA was further identified as a potential drug target for iCCA,which promoted cell proliferation by enhancing phosphatidic acid(PA)metabolism and activating mitogen-activated protein kinase(MAPK)signaling.Conclusion:Viamultiomics analyses,we identified three metabolic subtypes of iCCA,revealing that the S2 subtype exhibited the poorest survival outcomes.We further identified DGKA as a potential target for the S2 subtype.

AMPK-associated signaling to bridge the gap between fuel metabolism and hepatocyte viability

The adenosine monophosphate-activated protein kinase (AMPK) and p70 ribosomal S6 kinase-1 pathway may serve as a key signaling flow that regulates energy metabolism; thus, this pathway becomes an attractive target for the treatment of liver diseases that result from metabolic derangements. In addition, AMPK emerges as a kinase that controls the redox-state and mitochondrial function, whose activity may be modulated by antioxidants. A close link exists between fuel metabolism and mitochondrial biogenesis. The relationship between fuel metabolism and cell survival strongly implies the existence of a shared signaling network, by which hepatocytes respond to challenges of external stimuli. The AMPK pathway may belong to this network. A series of drugs and therapeutic candidates enable hepatocytes to protect mitochondria from radical stress and increase cell viability, which may be associated with the activation of AMPK, liver kinase B1, and other molecules or components. Consequently, the components downstream of AMPK may contribute to stabilizing mitochondrial membrane potential for hepatocyte survival. In this review, we discuss the role of the AMPK pathway in hepatic energy metabolism and hepatocyte viability. This information may help identify ways to prevent and/or treat hepatic diseases caused by the metabolic syndrome. Moreover, clinical drugs and experimental therapeutic candidates that directly or indirectly modulate the AMPK pathway in distinct manners are discussed here with particular emphasis on their effects on fuel metabolism and mitochondrial function.

Tumor pyruvate kinase M2:A promising molecular target of gastrointestinal cancer

Gastrointestinal(GI) cancer is one of the most common causes of cancer-related deaths worldwide.Tumor markers are valuable in detecting post-surgical recurrence or in monitoring response to chemotherapy.Pyruvate kinase isoform M2(PKM2),a glycolytic enzyme catalyzing conversion of phosphoenolpyruvate(PEP) to pyruvate,confers a growth advantage to the tumor cells and enables them to adapt to the tumor microenvironment.In this review,we have summarized current research on the expression and regulation of PKM2 in tumor cells,and its potential role in GI carcinogenesis and progression.Furthermore,we have also discussed the potential of PKM2 as a diagnostic and screening marker,and a therapeutic target in GI cancer.

Stress kinase inhibition modulates acute experimental pancreatitis

AIM: To examine the role of p38 during acute experimental cerulein pancreatitis. METHODS: Rats were treated with cerulein with or without a specific JNK inhibitor (CEP1347) and/or a specific p38 inhibitor (SB203580) and pancreatic stress kinase activity was determined. Parameters to assess pancreatitis included trypsin, amylase, lipase, pancreatic weight and histology. RESULTS: JNK inhibition with CEP1347 ameliorated pancreatitis, reducing pancreatic edema. In contrast, p38 inhibition with SB203580 aggravated pancreatitis with higher trypsin levels and, with induction of acinar necrosis not normally found after cerulein hyperstimulation. Simultaneous treatment with both CEP1347 and SB203580 mutually abolished the effects of either compound on cerulein pancreatitis. CONCLUSION: Stress kinases modulate pancreatitis differentially. JNK seems to promote pancreatitis development, possibly by supporting inflammatory reactions such as edema formation while its inhibition ameliorates pancreatitis. In contrast, p38 may help reduce organ destruction while inhibition of p38 during induction of cerulein pancreatitis leads to the occurrence of acinar necrosis.

Overexpression of PtPEPCK1 gene promotes nitrogen metabolism in poplar

To understand the function of phosphoenolpyruvate carboxylase kinase,we introduced PtPEPCK1 gene under the control of 35S promoter into 84K poplar(Populus alba×P.glandulosa).PtPEPCK1 gene is well-known for its role in gluconeogenesis.However,our data confi rmed that it has signifi cant eff ects on amino acid biosynthesis and nitrogen metabolism.Immunohistochemistry and fl uorescence microscopy indicate that PtPEPCK1 is specifi cally expressed in the cytoplasm of the spongy and palisade tissues.Overexpression of PtPEPCK1 was characterized through transcriptomics and metabolomics.The metabolites concentration of the ornithine cycle and its precursors also increased,of which N-acetylornithine was up-regulated almost 50-fold and ornithine 33.7-fold.These were accompanied by a massive increase in levels of several amino acids.Therefore,overexpression of PtPEPCK1 increases amino acid levels with urea cycle disorder.

Anti-arthritis effect of berberine associated with regulating energy metabolism of macrophage through AMPK/HIF-1α pathway

OBJECTIVE To investigate berberine(BBR)attenuates arthritis in adjuvant-induced arthritic(AA)rats associated with regulating the energy metabolism and correcting the polarization of macrophages through activation of AMP-activated protein kinase(AMPK)and inhibition of hypoxia inducible factor 1α(HIF-1α).METHODS AA rats were treated with BBR(40,80,or 160 mg·kg-1)from days 15 to 29 after immunization.The histopathology of ankle joint was examined through hematoxylin-eosin(HE)staining.The concentrations of tumour necrosis factor-α(TNF-α),interleukin-6(IL-6),IL-1β,IL-2,IL-17A,interferon-gamma(IFN-γ),monocyte chemotactic protein 1(MCP-1),IL-4,IL-10,transforming growth factor-β1(TGF-β1),ATP,and lactic acid were measured by using ELISA kits.The percentage of M1 and M2 macro⁃phage cells in joint tissues were evaluated by immune-fluorescence.The expressions of p-AMPK and HIF-1αin joint of AA rats were determined according to immunohistochemistry analysis.The migration of macrophage was detected by Transwell assays.The expression of inducible nitric oxide synthase(iNOS),Arginase-1(Arg1),p-AMPK,AMPK and HIF-1αwere examined by Western blotting.The labeled macrophages were observed with laser confocal microscopy.RESULTS BBR relieved signs and symptoms of AA rats and reversed pathological changes.BBR treatment group exhibited decreases in pro-inflammatory cytokines(TNF-α,IL-1β,IL-6,IL-2,IL-17A,IFN-γ,and MCP-1)coupled with increases anti-inflammatory cytokines(IL-4,IL-10,TGF-β1)in the serum.The number of M1 macrophage was reduced,while the number of M2 macrophage was increased in BBR group joint tissues.Moreover,BBR showed marked up-regu⁃lation the expression of p-AMPK and down-regulation the expression of HIF-1αin joint of AA rats.Next in vitro study,we found BBR up-regulated the expression of p-AMPK,Arg1(M2 marker)and down-regulated the expression of HIF-1α,iNOS(M1 marker)induced by LPS in peritoneal macrophages from normal SD rat.Furthermore,BBR treatment inhibited the migration of macrophages stimulated by LPS.The level of ATP was elevated and lactic acid was reduced in LPSinduced macrophages after treated by BBR.However,Compound C significantly attenuated the effects of BBR on acti⁃vated macrophages.CONCLUSION BBR alleviates inflammation by regulating energy metabolism and correcting the polarization of macrophage through AMPK-HIF-1αpathway.BBR might have great therapeutic value for RA.

Tale of two kinases:Protein kinase A and Ca^(2+)/calmodulin-dependent protein kinase Ⅱ in pre-diabetic cardiomyopathy

Metabolic syndrome is a pre-diabetic state characterized by several biochemical and physiological alterations,including insulin resistance,visceral fat accumulation,and dyslipidemias,which increase the risk for developing cardiovascular disease.Metabolic syndrome is associated with augmented sympathetic tone,which could account for the etiology of pre-diabetic cardiomyopathy.This review summarizes the current knowledge of the pathophysiological consequences of enhanced and sustainedβ-adrenergic response in pre-diabetes,focusing on cardiac dysfunction reported in diet-induced experimental models of pre-diabetic cardiomyopathy.The research reviewed indicates that both protein kinase A and Ca^(2+)/calmodulin-dependent protein kinase Ⅱ play important roles in functional responses mediated byβ1-adrenoceptors;therefore,alterations in the expression or function of these kinases can be deleterious.This review also outlines recent information on the role of protein kinase A and Ca^(2+)/calmodulin-dependent protein kinase Ⅱ in abnormal Ca^(2+)handling by cardiomyocytes from diet-induced models of pre-diabetic cardiomyopathy.

Pyrocincholic acid 3β-O-β-D-quinovopyranosyl-28-O-β-Dglucopyranoside suppresses adipogenesis and regulates lipid metabolism in 3T3-L1 adipocytes

Obesity is crucially involved in many metabolic diseases,such as type 2 diabetes,cardiovascular disease and cancer.Regulating the number or size of adipocytes has been suggested to be a potential treatment for obesity.In this study,we investigated the effect of pyrocincholic acid 3β-O-β-D-quinovopyranosyl-28-O-β-D-glucopyranoside(PAQG),a 27-nor-oleanolic acid saponin extracted from Metadina trichotoma,on adipogenesis and lipid metabolism in 3T3-L1 adipocytes.The 3T3-L1 pre-adipocytes were incubated with vehicle or PAQG for 6 days in differentiation process.PAQG significantly reduced the adipogenesis,adiponectin secretion and the expression level of key transcription factors related to adipogenesis,such as PPARc,C/EBPb,C/EBPa,and FABP4.Moreover,PAQG increased the levels of FFA and glycerol in medium and reduced TG level in mature adipocytes.Interestingly,PAQG not only promoted the activation of AMPK and genes involved in fatty oxidation including PDK4 and CPT1a,but also inhibited those genes involved in fatty acid biosynthesis,such as SREBP1c,FAS,ACCa and SCD1.In conclusion,PAQG inhibits the differentiation and regulates lipid metabolism of 3T3-L1 cells via AMPK pathway,suggesting that PAQG may be a novel and promising natural product for the treatment of obesity and hyperlipidemia.

Glycolysis in energy metabolism during seizures

Studies have shown that glycolysis increases during seizures, and that the glycolytic metabolite lactic acid can be used as an energy source. However, how lactic acid provides energy for seizures and how it can participate in the termination of seizures remains unclear. We reviewed possible mechanisms of glycolysis involved in seizure onset. Results showed that lactic acid was involved in seizure onset and provided energy at early stages. As seizures progress, lactic acid reduces the pH of tissue and induces metabolic acidosis, which terminates the seizure. The specific mechanism of lactic acid-induced acidosis involves several aspects, which include lactic acid-induced inhibition of the glycolytic enzyme 6-diphosphate kinase-1, inhibition of the N-methyl-D-aspartate receptor, activation of the acid-sensitive 1A ion channel, strengthening of the receptive mechanism of the inhibitory neurotransmitter Y-aminobutyric acid, and changes in the intra- and extracellular environment.

葛根芩连汤通过IRS-1/PI3K/AKT通路对胃肠湿热型2型糖尿病大鼠糖脂代谢的影响

目的探究葛根芩连汤通过胰岛素受体底物-1(IRS-1)/磷脂酰肌醇3激酶(PI3K)/蛋白激酶B(AKT)通路对胃肠湿热型2型糖尿病大鼠糖脂代谢的影响。方法将40只SD大鼠随机分为正常组(2 mL生理盐水灌胃)、造模组(2 mL生理盐水灌胃)、二甲双胍组(4.17 mg/100 g二甲双胍灌胃)和葛根芩连汤组(1 g/100 g葛根芩连汤灌胃),每组10只。采用高脂高糖饲料加腹腔注射链脲佐菌素(STZ)构建2型糖尿病大鼠模型,随后喂食油脂、42°白酒及蜂蜜水构建胃肠湿热型2型糖尿病大鼠模型。测量各组大鼠不同时间节点体质量,血糖仪测定空腹血糖(FBG);ELISA检测空腹胰岛素(FINS)、三酰甘油(TG)、总胆固醇(TC)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平变化、计算胰岛素抵抗指数(HOMA-IR);HE染色检测肝组织病理学变化;检测肝组织过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)及丙二醛(MDA)含量变化。Western blot检测肝组织IRS-1、PI3K、p-PI3K、AKT及p-AKT蛋白变化。结果与正常组比较,造模组大鼠体质量、FBG、FINS及HOMA-IR、GSH-Px、CAT、SOD、IRS-1、p-PI3K/PI3K及p-AKT/AKT水平均明显下降(P<0.05)、TG、TC、IL-6、TNF-α及MDA含量均显著升高(P<0.05),可见局灶性肝实质损失。与造模组比较,二甲双胍组及葛根芩连汤组大鼠体质量、FBG、FINS及HOMA-IR、GSH-Px、CAT、SOD、IRS-1、p-PI3K/PI3K及p-AKT/AKT水平均明显升高(P<0.05)、TG、TC、IL-6、TNF-α及MDA含量均显著降低(P<0.05),显示正常的肝实质。结论葛根芩连汤可明显改善胃肠湿热型2型糖尿病糖脂紊乱,可能是通过IRS-1/PI3K/AKT通路发挥作用。

基于转录组学分析PI3K/AKT通路对冷却滩羊肉贮藏期间肌肉代谢稳态的影响

为揭示磷脂酰肌醇3-激酶(phosphatidylinositol 3-kinase,PI3K)/蛋白激酶B(protein kinase B,AKT)信号通路在冷却滩羊肉贮藏期间代谢调控中的作用,采用高通量测序技术研究冷却滩羊肉经PI3K抑制剂LY294002注射处理后分别在贮藏期为0、4、8 d时转录组的变化。在对照组和LY294002处理组之间,0、4、8 d时被鉴定为显著差异表达基因(differentially expressed genes,DEGs)数分别为474、96、13。功能富集分析表明,DEGs主要与代谢稳态有关,如氨基酸的生物合成、糖酵解/糖异生、甘油脂类代谢过程。此外,组织切片分析显示,与对照组相比,LY294002组肌纤维间距增加,肌纤维直径显著减小,表明肌肉发生萎缩。结果表明,PI3K/AKT信号通路在维持滩羊肉贮藏过程中代谢平衡方面起着至关重要的作用,反过来又确保了肌肉的正常生长。研究为进一步阐明冷却滩羊肉贮藏中PI3K/AKT信号代谢稳态的分子机制提供了方向。

益气续骨方调节PI3K/Akt信号通路对激素性股骨头坏死大鼠骨代谢的影响

目的探究益气续骨方调节磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(Akt)信号通路对激素性股骨头坏死大鼠骨代谢的影响。方法将50只SD雄性大鼠随机分为正常组、模型组、益气续骨方低剂量组、益气续骨方高剂量组、益气续骨方+LY294002组,每组10只。除正常组外,其余组大鼠右臀肌肉注射醋酸泼尼松龙注射液4周建立激素性股骨头坏死模型。造模结束后,益气续骨方低、高剂量组大鼠分别给予益气续骨方0.5 mL(含生药0.285 g/mL)和1 mL(含生药0.57 g/mL)灌胃,益气续骨方+LY294002组大鼠给予益气续骨方1 mL灌胃并腹腔注射6 mg/kg的LY294002,正常组和模型组给予等体积生理盐水灌胃,均1次/d,连续干预8周。ELISA检测大鼠血清白细胞介素-4(IL-4)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、血钙、血磷、骨保护素(OPG)、骨钙素(OCN)、碱性磷酸酶(ALP)水平,Micro-CT检测观察股骨头形态,HE染色观察股骨头组织病理形态,TRAP染色观察破骨细胞生成情况,Western blot法检测股骨头组织中骨特异性转录因子2(Runx2)、骨形态发生蛋白2(BMP-2)、裂解半胱天冬酶-3(Cleaved-Caspase-3)、PI3K、Akt蛋白表达情况。结果与正常组比较,模型组大鼠血清IL-4、IL-6、TNF-α、OPG、ALP水平和骨小梁分离度(Tb.Sp)、空骨陷窝率及股骨头组织中Cleaved-Caspase-3蛋白相对表达量均明显升高(P均<0.05),血钙、血磷、OCN水平和骨体积分数(BV/TV)、骨小梁数目(Tb.N)、骨小梁厚度(Tb.Th)及股骨头组织中Runx2、BMP-2、p-PI3K/PI3K、p-Akt/Akt蛋白相对表达量均明显降低(P均<0.05),破骨细胞数量增多,股骨头破坏、骨小梁空间结构紊乱;与模型组比较,益气续骨方低、高剂量组大鼠血清IL-4、IL-6、TNF-α、OPG、ALP水平和Tb.Sp、空骨陷窝率及股骨头组织中Cleaved-Caspase-3蛋白相对表达量均明显降低(P均<0.05),血钙、血磷、OCN水平和BV/TV、Tb.N、Tb.Th及股骨头组织中Runx2、BMP-2、p-PI3K/PI3K、p-Akt/Akt蛋白相对表达量均明显升高(P均<0.05),破骨细胞数量减少,股骨头破坏程度减轻,骨小梁空间结构形态改善;LY294002可减弱益气续骨方对上述指标的改善作用,各指标与益气续骨方高剂量组比较差异均有统计学意义(P均<0.05)。结论益气续骨方可改善激素性股骨头坏死大鼠骨代谢,降低炎症因子水平,减少破骨细胞数量,减轻大鼠股骨头坏死,机制可能与激活PI3K/Akt信号通路有关。

丹参多糖对碘乙酸钠所致大鼠膝骨性关节炎的治疗作用及机制研究

探讨丹参多糖对碘乙酸钠所致大鼠膝骨性关节炎(knee osteoarthritis,KOA)的治疗作用及潜在机制。采用膝关节腔内注射碘乙酸钠法建立大鼠KOA模型,分为模型组、丹参多糖低、高剂量组(40、80 mg/kg)及塞来昔布组(20 mg/kg),另选取12只大鼠作为假手术组,持续干预4周后检测相关指标变化情况。结果发现,与模型组比较,丹参多糖低、高剂量组大鼠爪压评分及步态评分明显下降(P<0.05,P<0.01),机械性缩足反射阈值(mechanical withdrawal threshold,MWT)及热缩足反射潜伏期(thermal withdrawal latency,TWL)明显增加(P<0.01),关节软骨组织病理形态减轻,Markin评分明显降低(P<0.05,P<0.01);血清软骨寡聚基质蛋白(cartilage oligomeric matrix protein,COMP)、血清Ⅰ型胶原C末端肽(C-terminal peptide of type I collagen,CTX-Ⅰ)含量及关节软骨组织半胱氨酸蛋白酶-3(Caspase-3)、B淋巴细胞瘤-2(B-lymphoblastoma-2,Bcl-2)相关X蛋白(Bcl-2 associated X protein,Bax)mRNA表达明显下降(P<0.05,P<0.01),骨钙素(osteocalcin,OCN)含量及关节软骨组织Bcl-2 mRNA表达明显升高(P<0.05,P<0.01),关节滑液中肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-1β(interleukin-1β,IL-1β)、IL-6含量及关节软骨组织磷酸化丝裂原活化蛋白激酶p38(phosphorylated mitogen-activated protein kinase p38,p-p38 MAPK)、磷酸化核因子-κB p65(phosphorylated nuclear factor-κB p65,p-NF-κB p65)蛋白表达明显降低(P<0.05,P<0.01)。研究结果表明,丹参多糖对碘乙酸钠所致大鼠KOA具有治疗作用,其机制与改善骨代谢、抗凋亡及抑制MAPK/NF-κB信号通路介导的炎症反应有关。

基于AMPK通路探讨茶多酚改善糖尿病大鼠糖脂代谢机制

目的:探讨茶多酚从AMP活化蛋白激酶(AMPK)通路途径调控糖尿病大鼠糖脂代谢的机制。方法:经糖耐量试验筛选6周龄SD大鼠45只,按随机数字表法分为正常组10只和造模组35只,造模组糖尿病造模成功后剩余30只,根据体质量分层法和血糖水平分为模型组、二甲双胍组和茶多酚组,每组各10只。各组均于每日下午灌胃,正常组与模型组给予无菌生理盐水,二甲双胍组给予二甲双胍水溶液,茶多酚组给予茶多酚。干预120 d后,检测各组大鼠的空腹血糖(FBG)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C);酶联免疫吸附试验法检测肝脏乙酰辅酶A羧化酶(ACC)和激素敏感性脂肪酶(HSL);实时荧光定量法检测肝脏ACCmRNA、转录因子胆固醇调节元件结合蛋白1(SREBP-1)mRNA、3-羟基-3-甲基戊二酸单酰辅酶A还原酶(HMGCR)mRNA;免疫印迹法检测肝脏AMPKα1、磷酸化AMP活化蛋白激酶α1(P-AMPKα1)、SREBP1、HMGCR、肉毒碱棕榈酰转移酶1(CPT1)、葡萄糖转运蛋白4(GLUT4)和磷酸烯醇丙酮酸羧化激酶(PEPCK)。结果:与正常组比较,模型组大鼠的一般情况较差,FBG、TG、TC、LDL-C、ACC升高(P<0.05),SREBP1、HMGCR蛋白及mRNA表达升高(P<0.05),CPTI、PEPCK蛋白表达升高(P<0.05),HDL-C、HSL降低(P<0.05),AMPKα1、P-AMPKα1、GLUT4蛋白表达降低(P<0.05)。与模型组比较,茶多酚组大鼠的一般情况改善,TG、LDL-C、ACC降低(P<0.05),SREBP1、HMGCR蛋白及mRNA表达降低(P<0.05),PEPCK蛋白表达降低(P<0.05),HDL-C、HSL升高(P<0.05),AMPKα1、P-AMPKα1、GLUT4、CPT1蛋白表达升高(P<0.05)。与二甲双胍组比较,茶多酚组TC升高(P<0.05),FBG、TG、LDL-C、HDL-C、HSL、ACC、ACC mRNA、HMGCR mRNA、SREBP1 mRNA、AMPKα1、P-AMPKα1、SREBP1、HMGCR、CPT1、GLUT4、PEPCK相对表达量差异无统计学意义(P>0.05)。结论:茶多酚可能通过调节AMPK通路,影响HSL、HMGCR、SREBP1、CPTI、GLUT4和PEPCK,从而改善糖尿病大鼠糖脂代谢。

利拉鲁肽通过SIRT1/AMPK通路改善小鼠肝脏脂质变性的机制研究

目的探讨利拉鲁肽通过沉默信息调节因子1(silent information regulator 1,SIRT1)/腺苷酸活化蛋白激酶(adenosine monophosphate-activated protein kinase,AMPK)通路改善小鼠肝脏脂质变性的机制。方法将24只健康雄性6周龄C57BL/6J小鼠随机分为对照组、模型组、模型+利拉鲁肽组、模型+SIRT1组、模型+SIRT1+利拉鲁肽组、模型+SIRT1-NC组,每组4只。对照组普通饲料饲养,予以等容积生理盐水皮下注射,模型组高脂饲养12周建立代谢相关脂肪性肝病(metabolic dysfunction-associated fatty liver disease,MAFLD)模型,之后3周尾静脉注射SIRT1干扰慢病毒及利拉鲁肽。检测各组小鼠血清甘油三酯和丙氨酸氨基转移酶(alanine aminotransferase,ALT)水平,采用HE染色和油红O染色观察肝组织病理,采用实时荧光定量RT-PCR检测AMPK、SIRT1、肝激酶B1(liver kinase B1,LKB1)和去乙酰化固醇调节元件结合蛋白(sterol regulatory element binding protein-1c,SREBP-1c)基因表达水平,采用Western blot检测蛋白表达水平。结果利拉鲁肽可降低高脂喂养的C57BL/6J小鼠体质量、肝湿重、血清甘油三酯及ALT水平,油红O染色可见肝细胞脂滴减少。与模型组相比,模型+利拉鲁肽组SIRT1(0.212±0.110比0.076±0.010)、AMPK(0.518±0.051比0.248±0.023)、LKB1(1.023±0.039比0.576±0.029)基因表达量和AMPK(0.212±0.026比0.100±0.006)、LKB1(0.413±0.016比0.221±0.015)蛋白表达水平均上调,而SREBP-1c基因(0.727±0.249比9.007±1.530)和蛋白(0.187±0.008比0.824±0.114)表达水平均下调(P均<0.05)。与模型组相比,模型+SIRT1组SIRT1(0.029±0.003比0.076±0.010)、AMPK(0.105±0.013比0.248±0.023)、LKB1(0.333±0.106比0.576±0.029)基因表达量均下调(P均<0.05)。与模型+SIRT1组相比,模型+SIRT1+利拉鲁肽组LKB1(0.945±0.110比0.333±0.106;0.380±0.004比0.145±0.014)、AMPK(0.319±0.051比0.105±0.013;0.181±0.039比0.051±0.012)基因表达量和蛋白表达量均上调,而SREBP-1c基因表达量(4.239±0.554比12.740±0.976)下调(P均<0.05)。结论利拉鲁肽改善C57BL/6J小鼠肝脏脂毒性可能通过直接上调SIRT1/AMPK通路信号分子基因和蛋白表达水平,或间接激活LKB1并增强AMPK基因和蛋白表达、拮抗SREBP-1c基因和蛋白表达,从而降低脂质合成相关分子水平,而干扰SIRT1表达削弱了利拉鲁肽上调SIRT1/AMPK通路改善肝脏脂肪变性的作用。