Oligomannuronate-Chromium (Ⅲ) Complex Ameliorates Insulin Resistance in C57BL/KsJ-db/db Mice

Diabetes mellitus is the most common metabolic disease and its prevalence is increasing in many countries year by year.More than 90% of diabetes patients are type 2 diabetes,which is caused by insulin resistance and beta-cell dysfunction.In this paper,the oligomannuronate-chromium(III)complex(OM2)was prepared and its effect and mechanism on attenuating insulin resistance in diabetic C57BL/KsJ-db/db mice were studied.The results indicated that oral intake of OM2(50 mg kg-1d-1)for 42 d decreased blood glucose and lipid concentration,which was associated with the reduced serum insulin concentration and insulin resistance.According to western blot assay,OM2 could activate AMPK pathway to regulate glycogen synthesis,gluconeogenesis and lipid metabolism in the liver,and attenuate the hyperglycemic symptom in db/db mice.The effects of OM2 on attenuating insulin resistance were com-parable to that of the established antidiabetic drug metformin,and OM2 showed less adverse effect than metformin in vivo.Based on the effectiveness and low toxicity,OM2 may potentially be used for prevention and treatment of type 2 diabetes mellitus.

Pluronic L-81 ameliorates diabetic symptoms in db/db mice through transcriptional regulation of microsomal triglyceride transfer protein

AIM: To test whether oral L-81 treatment could im-prove the condition of mice with diabetes and to investigate how L-81 regulates microsomal triglyceride transfer protein (MTP) activity in the liver. METHODS: Genetically diabetic (db/db) mice were fed on chow supplemented with or without L-81 for 4 wk. The body weight, plasma glucose level, plasma lipid profile, and adipocyte volume of the db/db mice were assessed after treatment. Toxicity of L-81 was also evaluated. To understand the molecular mecha-nism, HepG2 cells were treated with L-81 and the effects on apolipoprotein B (apoB) secretion and mRNA level of the MTP gene were assessed.RESULTS: Treatment of db/db mice with L-81 sig-nificantly reduced and nearly normalized their body weight, hyperphagia and polydipsia. L-81 also markedly decreased the fasting plasma glucose level, improved glucose tolerance, and attenuated the elevated levels of plasma cholesterol and triglyceride. At the effective dosage, little toxicity was observed. Treatment of HepG2 cells with L-81 not only inhibited apoB secretion, but also signif icantly decreased the mRNA level of the MTP gene. Similar to the action of insulin, L-81 exerted its effect on the MTP promoter. CONCLUSION: L-81 represents a promising candidate in the development of a selective insulin-mimetic mol-ecule and an anti-diabetic agent.

Investigation of the apoptotic mechanism in hippocampal and retinal neurons of db/db mice induced by Dihuangyinzi decoction

In the present study,we utilized db/db mice to investigate the mechanisms of apoptosis in brain and retinal neurons.A total of 30 male db/db mice aged 8–9 weeks were randomly assigned to the model group,Dihuangyinzi decoction(DHYZ)group(30.03 g/kg),and metformin(MET)group(0.58 g/kg),with 10 mice in each group.The control group comprised 10 db/m mice of the same background and age.Paired-associate learning(PAL)tests were conducted to evaluate the learning and memory functions of the mice.Histological assessments,including Hematoxylin-Eosin(H&E)and Nissl staining,were employed to observe changes in nerve cells in the hippocampus and retina.Immunohistochemistry and real-time fluorescence quantitative PCR were employed to detect the positive expression of anti-apoptotic factor Bcl-2 and pro-apoptotic factor Bax at the protein and mRNA levels in the hippocampus and retina.Western blotting analysis was adopted to assess protein expression levels of JNK,p-JNK,p38 MAPK,and p-p38 MAPK.Results revealed a significant decline in the correct rate of PAL test results in the model group(P<0.001),accompanied by increased reaction and delay times(P<0.001)and higher blood glucose levels(P<0.001).H&E and Nissl staining indicated a reduction in the number of nerve cells in the CA1 area of the hippocampus in the model group,with scattered arrangement and decreased Nissl corpuscles.Positive expression and mRNA expression of Bax in the hippocampus and retina increased significantly(P<0.001),while positive expression and mRNA expression of Bcl-2 decreased(P<0.001).Protein expression levels of p-JNK/JNK and p-p38 MAPK/p38 MAPK showed a significant increase(P<0.001).The DHYZ and MET groups exhibited enhanced accuracy in PAL experiments(P<0.05),decreased reaction time and delay time(P<0.05),and reduced blood glucose levels(P<0.05).The number of neurons in the CA1 region of the hippocampus increased,morphological structure improved,and the arrangement of the hippocampal structure became more orderly.Additionally,no obvious vacuolization was observed in the neuronal cell layer.The number of Nissl bodies increased,and the layers of the retina were closely arranged,with an increase in the number of Nissl bodies.Positive expressions of Bax in the hippocampus and retina,both at the protein and mRNA levels,decreased significantly(P<0.001),while positive expressions of Bcl-2 and its mRNA increased(P<0.01,P<0.001).Furthermore,the protein expressions of p-JNK/JNK and p-p38 MAPK/p38 MAPK decreased significantly(P<0.01).This study suggested that DHYZ decoction could inhibit the JNK/p38 MAPK signaling pathway,thereby increasing the anti-apoptotic factor Bcl-2 and reducing the expression of the pro-apoptotic factor Bax,consequently inhibiting apoptosis in the hippocampal CA1 region and retinal neurons of db/db mice.

Effects of 95%ethanol extract of Aquilaria sinensis leaves on hyperglycemia in diabetic db/db mice

The leaves of Aquilaria sinensis（Lour.） Gilg have been used in folk medicine for the treatment of diabetes in Guangdong Province,China.In this study,effects of ethanol extract of Aquilaria sinensis leaves on hyperglycemia were investigated in diabetic db/db mice.After 4 weeks of administration,the 95%ethanol（EtOH） extract of Aquilaria sinensis leaves （AE）,especially at high dose level（600 mg/kg）,activated AMP-activated protein kinase（AMPK）,resulting in reduced fasting blood glucose and glycosylated hemoglobin levels in db/db mice.In addition,the oral glucose tolerance test（OGTT test） showed that AE could remarkably improve insulin resistance.Compared to Thiazolinediones（TZDs）,no weight gain was observed after AE administration,which is a severe side effect of TZDs.The data suggested that AE could act as an activator of AMPK,and might be used as an alternative to TZDs in the management of obesity-related diabetes.

Effects of phlorizin on vascular complications in diabetes db/db mice

Background Diabetic macrovascular complications are important causes of cardiovascular and cerebrovascular diseases and also one of the major causes of morbidity and mortality in patients with type 2 diabetes mellitus （T2DM）. Phlorizin has been reported to be effective in reducing the blood glucose level in diabetic mellitus, while little is known about its effects on vascular complications. This study aimed to observe the effects of phlorizin on the aorta of diabetes db/db mice and explore its mechanism. Methods Diabetic db/db mice （n=16） and age-matched db/m mice （n=8） were divided into three groups： normal control group （CC group, db/m mice, n=8）, untreated diabetic group （DM group, db/db mice, n=8） and diabetic group treated by phlorizin （DMT group, db/db mice, n=8）. Phlorizin （20 mg/kg body weight） was given in normal saline solution intragastrically for 10 weeks. Animals were weighed weekly. At the 10th weekend, all mice were fasted overnight and then sacrificed. Fasting blood was collected, and the aortas were dissected. The blood samples were analyzed for fasting blood glucose （FBG）, serum advanced glycation end products （AGEs）, malondialdehyde （MDA） and superoxide dismutase （SOD） activity, the aortic ultrastructure was studied. Results The weight and serum concentration of FBG, AGEs, and MDA in the DM group were higher than that in the CC group （P 〈0.01 ）, and they were significantly lower in the DMT group （P 〈0.05）. Serum SOD activity was lower than that in the CC group （P 〈0.01）, and it is significantly higher in the DMT group （P 〈0.05）. The severity of aorta damage in the DMT group was less than that in the DM group. Conclusions Phlorizin protected the db/db mice from diabetic macrovascular complications, attributed to the decreasing of blood glucose and AGEs level, and its antioxidant potential. This study may provide a new natural medicine for treating diabetic macrovascular complications.

Alterations of the Ca2＋ signaling pathway in pancreatic beta-cells isolated from db/db mice

Upon glucose elevation, pancreatic beta-cells secrete insulin in a Ca2＋-dependent manner. In diabetic animal models, different aspects of the calcium signaling path- way in beta-cells are altered, but there is no consensus regarding their relative contributions to the development of beta-cell dysfunction. In this study, we compared the increase in cytosolic Ca2＊ （[Ca2＊]~） via Ca2＋ influx, Ca2＊ mobilization from endoplasmic reticulum （ER） calcium stores, and the removal of Ca2＋ via multiple mechanisms in beta-cells from both diabetic db/db mice and non- diabetic C57BL/6J mice. We refined our previous quan- titative model to describe the slow [Ca2＋]i recovery after depolarization in beta-cells from db/db mice. According to the model, the activity levels of the two subtypes of the sarco-endoplasmic reticulum Ca2＋-ATPase （SERCA） pump, SERCA2 and SERCA3, were severely down-reg- ulated in diabetic cells to 65% and 0% of the levels in normal cells. This down-regulation may lead to a reduc- tion in the Ca2＋ concentration in the ER, a compensatory up-regulation of the plasma membrane Na＋/Ca2＋ exchanger （NCX） and a reduction in depolarizationevoked Ca2＋ influx. As a result, the patterns of glucosestimulated calcium oscillations were significantly different in db/db diabetic beta-cells compared with normal cells. Overall, quantifying the changes in the calcium signaling pathway in db/db diabetic beta-cells will aid in the development of a disease model that could provide insight into the adaptive transformations of beta-cell function during diabetes development.

基于高通量测序分析毛菊苣醇提物对db/db小鼠肠道菌群的影响

该文探究毛菊苣醇提物对糖尿病小鼠(db/db小鼠)肠道菌群的影响。该研究以m/m小鼠为正常对照组(CON组),db/db小鼠随机分为模型组(MOD组)、二甲双胍组(MET组)、毛菊苣醇提物低剂量组(CGL组)、毛菊苣醇提物高剂量组(CGH组)。灌胃给药8周,对小鼠体质量、空腹血糖、肝脏总胆固醇(TC)、甘油三酯(TG)进行分析,对小鼠粪便进行16S rRNA测序分析,探究毛菊苣醇提物对小鼠肠道菌群的影响。毛菊苣醇提物高剂量组可调节db/db小鼠体质量及血糖,显著降低db/db小鼠TC、TG水平(P<0.05);测序结果显示CON组、MOD组、CGH组三组小鼠肠道菌群情况存在差异,毛菊苣醇提物给药可改善db/db小鼠的肠道菌群失调,上调db/db小鼠肠道菌群中有益菌双歧杆菌属(Bifidobacterium)、Romboutsia、普雷沃氏菌属(Prevotella)菌群相对丰度。研究证明了毛菊苣醇提物给药能调节db/db小鼠肠道菌群,通过提高有益菌相对丰度调节糖脂代谢,可为新疆地产毛菊苣药材资源的开发利用提供全新的研究思路。

肉苁蓉不同提取部位对db/db小黑鼠降血糖作用

目的探讨肉苁蓉和酒苁蓉不同提取部位对db/db小黑鼠降血糖的作用及机制。方法富集肉苁蓉和酒苁蓉总多糖、总寡糖和总苷部分,对其含量进行了比较分析。选用db/db小黑鼠为实验动物,给药28 d后,记录小黑鼠体重、进食量、饮水量,检测血糖,采用ELISA检测血清胰岛素(INS)、糖化血红蛋白(HbA1c),肝脏甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白(LDL-C)、高密度脂蛋白(HDL-C)、丙二醛(MDA)、超氧化物歧化酶(SOD),血浆和尿液中尿酸(UA)、肌酐(Cr)以及尿微量白蛋白(mALB)水平;HE染色方法制备胰腺和肾脏组织病理切片;IHC测定肾脏type-Ⅳ collagen蛋白表达水平。结果肉苁蓉多糖部位经过酒蒸后含量下降,肉苁蓉寡糖部位中的甜菜碱经过酒蒸后含量增加,总苷类成分酒蒸后松果菊苷的含量稍有下降,毛蕊花糖苷含量下降,异类叶升麻苷含量上升。与模型组相比,肉苁蓉和酒苁蓉不同提取部位能降低体重、空腹血糖(FBG)、口服葡萄糖耐量(OGTT)、HbA1c、胰岛素抵抗指数(HOMA-IR)、胰岛β细胞分泌指数(HOMA-β)、MDA、LDL-C、UA、Cr以及mALB,INS和HDL-C有上升趋势(P<0.05,P<0.01),且能改善胰腺和肾脏的病理损伤以及type-Ⅳ collagen的表达。结论肉苁蓉和酒苁蓉总苷组降血糖作用较好,酒苁蓉多糖和寡糖也有一定的降血糖作用。

Global gene expression analysis in liver of db/db mice treated with catalpol

Catalpol,a major bioactive component from Rehmannia glutinosa,which has been used to treat diabetes.The present study was designed to elucidate the anti-diabetic effect and mechanism of action for catalpol in db/db mice.The db/db mice were randomly divided into six groups(10/group) according to their blood glucose levels:db/db control,metformin(positive control),and four dose levels of catalpol treatment(25,50,100,and 200 mg·kg^(-1)),and 10 db/m mice were used as the normal control.All the groups were administered orally for 8 weeks.The levels of fasting blood glucose(FBG),random blood glucose(RBG),glucose tolerance,insulin tolerance,and glycated serum protein(GSP) and the globe gene expression in liver tissues were analyzed.Our results showed that catalpol treatment obviously reduced water intake and food intake in a dose-dependent manner.Catalpol treatment also remarkably reduce fasting blood glucose(FBG) and random blood glucose(RBG) in a dose-dependent manner.The RBG-lowering effect of catalpol was better than that of metformin.Furthermore,catalpol significantly improved glucose tolerance and insulin tolerance via increasing insulin sensitivity.Catalpol treatment significantly decreased GSP level.The comparisons of gene expression in liver tissues among normal control mice,db/db mice and catalpol treated mice(200 and 100 mg·kg^(-1)) indicated that there were significant increases in the expressions of 287 genes,whichwere mainly involved in lipid metabolism,response to stress,energy metabolism,and cellular processes,and significant decreases in the expressions of 520 genes,which were mainly involved in cell growth,death,immune system,and response to stress.Four genes expressed differentially were linked to glucose metabolism or insulin signaling pathways,including Irs1(insulin receptor substrate 1),Idh2(isocitrate dehydrogenase 2(NADP+),mitochondrial),G6pd2(glucose-6-phosphate dehydrogenase 2),and SOCS3(suppressor of cytokine signaling 3).In conclusion,catalpol ecerted significant hypoglycemic effect and remarkable therapeutic effect in db/db mice via modulating various gene expressions.

A new long-acting GLP-1 derivative KTP ameliorates hyperglycemia and dyslipidemia and improves pancreas and fatty liver in db/db mice

Glucagon-like peptide-1 (GLP-1) is a polypeptide incretin hormone that glucose-dependently promotes the secretion and synthesis of insulin. However, its half-life is extremely short. To enhance its half-life, we developed a long-acting GLP-1 derivative KTP with controlled release, designed on the basis of another GLP-1 derivative GP62. The kinetics and bioactivity of KTP were evaluated in Sprague Dawley (SD) rats. Long-term treatment of KTP was performed in db/db mice. Mice were treated twice daily with subcutaneous injections of KTP (1.2 mg/kg body weight), Exendin-4 (0.1 mg/kg body weight) or vehicle (phosphate buffered saline (PBS), pH 7.4) for 60 d. KTP had a longer half-life, as well as further increasing the secretion and production of insulin and reducing blood glucose concentrations, than GP62. Long-term treatment with KTP also induced anorexia, decreased water and food intake, decreased weight gain, improved blood glucose and blood lipid and ameliorated pancreatic damage and fatty liver in db/db mice.

基于转录组学探讨当归芍药散对db/db小鼠肾脏保护作用的潜在机制

目的基于转录组学和实验验证探究当归芍药散对db/db糖尿病肾病小鼠肾脏的保护机制。方法25只8周龄造模成功的db/db小鼠按体质量随机均分为模型组(20 mL/kg蒸馏水)、达格列净组(1.3 mg/kg)、当归芍药散低剂量组(8.39 g/kg)、当归芍药散中剂量组(16.77 g/kg)、当归芍药散高剂量组(33.54 g/kg),每组5只;另选5只同龄db/m小鼠作为空白组(20 mL/kg蒸馏水)。每组灌胃1次/d,连续6周。给药结束后,检测各组小鼠体质量、空腹血糖(fasting blood glucose,FBG)、口服糖耐量试验(oral glucose tolerance test,OGTT)的曲线下面积(area under thecurve,AUC);采用全自动生化分析仪检测尿白蛋白肌酐比值(urea albumin creatinine ratio,UACR)、甘油三酯(triglyceride,TG)、总胆固醇(total cholesterol,TC);采用肌酐比色法检测血肌酐(serum creatinine,Scr);采用尿素比色法检测小鼠血尿素氮(blood urea nitrogen,BUN);采用HE染色观察肾脏组织病理形态;采用转录组学芯片技术检测小鼠肾组织差异基因,并对当归芍药散中剂量组差异基因进行KEGG富集分析;采用RT-PCR法检测表达量TPM>10的核心基因在肾脏组织中的mRNA表达水平。结果与空白组比较,模型组小鼠体质量、OGTT-AUC、FBG、UACR、Scr、BUN、TG、TC显著升高(P<0.01)。与模型组相比,达格列净组、当归芍药散各剂量组小鼠体质量、OGTT-AUC、FBG、UACR、Scr、BUN、TG、TC均降低(P<0.05,P<0.01)。与空白组相比,模型组共筛选出1129个差异基因,其中上调差异基因337个、下调差异基因792个。与模型组相比,当归芍药散共筛选出271个差异基因,其中上调差异基因195个、下调差异基因76个。空白组、模型组、当归芍药散中剂量组三组差异共表达基因57个,其中TPM>10的核心基因共12个,包括Gsta2、Cyp4a12a、Slc8a1、Abcc4、Cpeb4、Serpina1b、Npl、Aacs、Kap、Slc5a10、Tmem252、Ifi27l2a。12个核心基因的mRNA表达水平与转录组测序趋势相同。与模型组比较,当归芍药散中剂量组小鼠Gsta2、Abcc4、Slc8a1、NPL mRNA表达水平升高(P<0.05,P<0.01),Slc5a10、Tmem252 mRNA表达水平下降(P<0.05)。当归芍药散中剂量组差异基因富集于药物代谢-细胞色素P450、谷胱甘肽代谢、活性氧等相关通路。结论当归芍药散具有改善糖尿病肾病预后的作用,其机制可能与调控Gsta2、Slc5a10、Abcc4、Slc8a1、Tmem252、Npl等基因表达,调控细胞色素P450、谷胱甘肽代谢、活性氧等信号通路相关。

Transfusion of CXCR4-priming endothelial progenitor cells reduces cerebral ischemic damage and promotes angiogenesis and neurogenesis in db/db diabetic mice

Previous studies suggest that reduction and dysfunction of circulating endothelial progenitor cells(EPCs),and dysregulation in stromal cell derived factor-1/CXC-chemokine receptor 4(SDF-1/ CXCR4) axis in diabetes could be therapeutic targets for diabetic ischemic stroke.This study investigated the efficacy of CXCR4-priming EPCs on cerebral repair following ischemic stroke in db/db diabetic mice.Bone marrow derived EPCs from db/+ control mice were transfected with adenovirus(1×10~7 IU) carrying CXCR4(Ad-CXCR4-EPCs)or null(Ad- null-EPCs).The db/db mice were divided into three groups for EPCs injection(2×10~5 cells/100μl): Ad-CXCR4-EPCs,Ad-null-EPCs or saline(vehicle), via tail vein 2 hrs after middle cerebral artery occlusion (MCAO) surgery.Cerebral blood flow(CBF) was measured with laser Doppler flowmeter.Mice were sacrificed at 2 or 7 days thereafter.Level of circulating EPCs was measured by flow cytometry. Ischemic damage,cerebral microvascular density (MVD),angiogenesis and neurogenesis were determined by histological staining with Fluoro-J,CD31, CD31 +BrdU,NeuN +BrdU,GFAP+BrdU,respectively. Results(table) showed:1) Levels of CXCR4 expression were reduced in the brain and EPCs of db/db mice as measured by real-time RT-PCR and western blot analyses(data not shown);2) The level of circulating EPCs was more in the mice treated with Ad-CXCR4-EPCs;3)EPC transfusion improved CBF,increased MVD,angiogenesis and neurogenesis in peri-infarct area,and decreased ischemic damage.The efficacies were better in Ad-CXCR4 -EPCs group.Data suggest that transfusion of Ad-CXCR4-EPCs could be a therapeutic avenue for ischemia stroke in diabetes.

4种谷物膳食纤维对db/db小鼠血糖和炎症因子及肠道菌群的影响

研究4种谷物膳食纤维(DF)对db/db小鼠血糖和炎症因子及肠道菌群的影响。用含有小麦(WDF)、糙米(BDF)、燕麦(ODF)和荞麦(BWDF)4种膳食纤维的日粮分别饲喂db/db小鼠,每两周测定空腹血糖(FBG)水平,并在第8周和14周时进行口服葡萄糖耐量实验(OGTT)。14周时,采集粪便,分析菌群变化情况;收集血清,测定血脂和炎症因子水平。4种谷物DF均可降低db/db小鼠FBG和8周血糖曲线下面积(AUC)水平,改善血脂异常并降低血液促炎因子浓度(P<0.05)。4种谷物DF均可提高肠道菌群多样性,并改变不同菌群的丰度。其中,WDF主要增加粪杆菌属(Faecalibaculum)和罗姆布茨菌(Romboutsia)丰度;BDF增加了放线菌门(Actinobacteriota)丰度和厚壁菌门与拟杆菌门比例(F/B);ODF主要促进了另枝菌属(Alistipes)的增殖;BWDF增加了norank_f__Muribaculaceae丰度并降低了拟杆菌属(Bacteroides)水平。相关性分析显示F/B和Actinobacteriota与FBG、AUC、促炎因子(IL-8)及低密度脂蛋白胆固醇(LDL-C)水平呈显著负相关,与抗炎因子(IL-10)和高密度脂蛋白胆固醇(HDL-C)水平呈正相关,而Bacteroides与之相反;Alistipes、Faecalibaculum、Romboutsia分别与促炎因子IL-1β、IL-8、TNF-α呈负相关。4种谷物DF可通过增加肠道菌群多样性及对菌群的不同调节作用,改善2型糖尿病db/db小鼠的糖脂代谢紊乱和炎症反应。

青风藤活性成分对糖尿病db/db小鼠氧化应激、炎症反应及免疫功能的影响

目的:探讨青风藤活性成分对糖尿病(diabetes mellitus,DM)db/db小鼠肾脏的保护作用及其机制研究。方法:30只6周龄雄性db/db小鼠随机分为模型组(等体积生理盐水),阳性组(195 mg/kg/d羟苯磺酸钙),盐酸青藤碱(Sinomenine Hydrochloride,SH)低、中、高剂量组(31.2、62.4、124.8 mg/kg/d SH)5组,同时选取6只同周龄db/m小鼠设为对照组(等体积生理盐水),每日1次,定时灌胃给药,连续6 w。于12 w末观察各组小鼠一般情况,检测尿微量白蛋白(mAlb)、血肌酐(SCr)和血尿素氮(BUN)水平;试剂盒检测肾组织匀浆中丙二醛(MDA)、还原型谷胱甘肽(GSH)和超氧化物歧化酶(SOD)的水平;Luminex多因子检测技术测定血清肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和白细胞介素-10(IL-10)的含量;ELISA法检测血清免疫球蛋白G(IgG)、免疫球蛋白M(IgM)、免疫球蛋白A(IgA)及补体蛋白3(C3)的水平;苏木精-伊红(HE)和过碘酸-雪夫(PAS)染色观察肾脏组织病理形态变化;透射电镜观察肾脏超微结构的改变。结果:与模型组比较,阳性组和SH低、中、高剂量组小鼠mAlb、SCr和BUN水平均降低(P<0.05);肾组织匀浆中MDA水平降低(P<0.05),GSH水平和SOD活性均升高(P<0.05);血清中TNF-α、IL-1β、IL-6、IgG、IgM、IgA和补体C3水平均降低(P<0.05),IL-10水平升高(P<0.05);镜下肾小球损伤及肾小管上皮水肿情况均有所改善,肾组织损伤减轻。结论:青风藤活性成分对DM db/db小鼠的肾脏具有保护作用,其作用机制可能与改善氧化应激反应,缓解炎症反应及提高免疫功能有关。

大黄酸和罗格列酮对db/db糖尿病小鼠代谢紊乱和肾脏损伤的作用比较

目的 :比较大黄酸和罗格列酮对糖尿病db/db小鼠代谢紊乱和肾脏损伤的作用 ,探讨大黄酸防治糖尿病肾病的机制。 方法 :实验小鼠分四组 :db/m正常小鼠对照组 ;db/db糖尿病小鼠对照组 ;db/db糖尿病小鼠大黄酸 [1 2 0mg/ (Kg·d) ]治疗组 ;db/db糖尿病小鼠罗格列酮 [4mg/ (Kg·d) ]治疗组。连续灌胃 1 2周 ,于实验末比较各组体重、血糖和血脂水平。PAS染色、免疫荧光分析肾小球病理形态学改变。电镜分析线粒体数目形态改变。Real timePCR分析脂肪和肌肉组织过氧化物酶体增生物激活受体γ(PPARγ)、胰岛素抵抗因子 (resistin)和脂肪酸转运体 (FAT/CD36 )mRNA表达。 结果 :大黄酸和罗格列酮治疗均可明显降低db/db小鼠血糖水平。大黄酸治疗还可明显减轻体重 ,降低血胆固醇和三酰甘油水平 ,改善高脂血症 ;而罗格列酮治疗则增加小鼠体重 ,提高血胆固醇和低密度脂蛋白水平。组织学显示 ,db/db小鼠肾小球肥大 ,系膜区扩张 ,系膜基质增加 ,大量纤维连接蛋白 ;同时肾小管线粒体数目减少 ,体积增大 ,嵴结构不清。大黄酸和罗格列酮治疗后均可明显改善上述肾脏病理改变 ,但对线粒体的作用大黄酸较罗格列酮更为明显。db/db小鼠肌肉和脂肪组织PPARγ和resistin的表达均明显下降 ,FAT/CD36表达增加。

过敏毒素受体(C3aR)在db/db糖尿病肾病小鼠肾脏中的表达及病理意义分析

利用半定量RT-PCR、免疫组化和Western blotting的方法,同时从mRNA水平和蛋白质水平对过敏毒素受体(C3aR)在不同病理阶段的2型糖尿病肾病模型小鼠——db/db小鼠肾脏中的表达情况进行了较为系统的分析.结果发现:a.在糖尿病前的db/db小鼠(4周龄的db/db小鼠),C3aR与作为正常对照的db/m小鼠相比没有明显差异.随着肥胖的加剧,高血糖、蛋白尿的发生和发展,C3aR在db/db小鼠肾脏中的表达显著升高.b.免疫组化分析显示,C3aR广泛地表达于db/m和db/db小鼠肾脏的皮质和髓质,分布于肾脏的上皮细胞中(包括肾小管上皮细胞、肾小球中的脏层上皮细胞(足细胞)和壁层上皮细胞).从部位来看,皮髓交界处的肾小管中C3aR表达量明显要比其他部位的多.在肾小球,C3aR特异地存在于足细胞部位.在db/m小鼠,不同周龄小鼠肾脏中C3aR的表达量并没有明显变化,但在db/db小鼠,从8周龄开始,分布在db/db小鼠肾小管上皮细胞和小球足细胞中的C3aR均随小鼠周龄的增加而增加,至少在时间上,与小鼠糖尿病肾病的发生发展相关,其中尤以足细胞中和皮髓交界处肾小管上皮细胞中的变化最为明显.c.在糖尿病肾病小鼠中高表达C3aR的肾小管上皮细胞常有空泡变性的情况.上述工作印证了先前对2型糖尿病肾病患者肾小球基因表达谱的分析结果,更加明确了C3aR与糖尿病肾病的相关性,同时揭示了C3aR在正常小鼠和糖尿病肾病小鼠肾脏中的表达、分布和变化规律,有利于进一步揭示C3aR的功能及其在糖尿病肾病发生、发展过程中的可能作用,探讨糖尿病肾病的分子机制。

红芪多糖对糖尿病肾病db/db小鼠肾功能和肾脏组织中GluT-1 mRNA和蛋白表达水平的影响

目的:探讨红芪多糖对糖尿病肾病(DN)db/db小鼠肾功能和肾脏组织中葡萄糖转运蛋白-1(GluT-1)的mRNA和蛋白表达的影响,阐明其可能的作用机制。方法:将10只db/m小鼠作为正常对照组;50只肥胖型2型糖尿病模型db/db小鼠随机分为模型组,依那普利组,红芪多糖低、中和高剂量组;每组10只。正常对照组和模型组小鼠分别灌胃给予生理盐水0.5 mL·kg-1·d-1,其他各组小鼠分别灌胃给予依那普利10mg·kg-1·d-1和红芪多糖100、200和400mg·kg-1·d-1,共8周。苦味酸法测定小鼠血肌酐(SCr)水平,酶偶联速率法测定血尿素氮(BUN)水平,ELISA法测定24h尿微量白蛋白(UMALB)水平;RT-PCR法测定小鼠肾脏组织中GluT-1mRNA的表达;Western blotting法和免疫组织化学法测定小鼠肾脏组织中GluT-1蛋白的表达。结果:与模型组比较,依那普利组和红芪多糖各剂量组SCr、BUN、UMALB和GluT-1mRNA及蛋白表达水平均降低,其中红芪多糖高剂量组和依那普利组降低明显(P<0.01)。HE及Masson染色,红芪多糖高剂量组小鼠肾小球内炎症细胞浸润较少,毛细血管腔通畅,肾小管及肾间质内胶原蛋白沉积不明显。结论:红芪多糖可改善db/db小鼠的肾功能并明显抑制GluT-1mRNA和蛋白的表达,提示红芪多糖可能通过抑制肾小球系膜细胞膜上GluT-1的表达而延缓DN的发展。

红芪多糖对db/db小鼠糖尿病心肌病心肌NF-κB p65与MMP-9表达的影响

目的:观察红芪多糖(HPS)对db/db小鼠心肌组织核转录因子(NF-κB p65)、基质金属蛋白酶-9(MMP-9)蛋白与mRNA表达的影响,探讨其防治心肌间质纤维化可能的作用机制.方法 :将60只雄性db/db小鼠随机分为5组:HPS高、中、低剂量组,罗格列酮组与模型组;12只雄性db/m小鼠为正常组.干预组小鼠连续灌胃8周,于干预前后每2周测空腹血糖、体质量各1次.第8周末心脏取血后,取心脏左室心肌组织,分别用于Masson染色、电镜观察心脏超微结构以及Western blotting、逆转录-免疫酶联反应(RT-PCR)法检测其NF-κB p65、MMP-9的蛋白与mRNA表达情况.结果:HPS干预8周后,与模型组比较:HPS高、中剂量组与罗格列酮组小鼠血糖下降明显(P<0.05),干预组小鼠体质量变化无明显差异(P>0.05);Masson染色可见亮绿色胶原纤维在心肌细胞间及血管周围明显增多且呈堆积状分布;电镜观察可见HPS高剂量组与罗格列酮组小鼠心肌组织内线粒体数量与破坏程度、糖原颗粒及脂滴沉积现象均有明显改善;Western blotting、RT-PCR检测结果显示,HPS高剂量组、罗格列酮组小鼠心肌组织中NF-κB p65、MMP-9的蛋白与mRNA表达量均明显降低(P<0.05).结论:HPS可降低db/db小鼠心肌组织中NF-κB p65、MMP-9蛋白与mRNA的表达水平,减轻其炎症反应状态,对心肌的间质纤维化病变具有一定的防治作用.

姜黄素对db/db小鼠肾组织p-STAT3及IκB蛋白的影响

目的:观察姜黄素对db/db小鼠糖尿病肾病的疗效,并探讨其可能的作用机制。方法:雌性db/db小鼠10只,随机分为模型组和姜黄素治疗组,5只db/m小鼠为正常对照组,姜黄素治疗组予以姜黄素200 mg/(kg·d)连续灌胃18周。实验结束时,尾静脉采血测血糖,ELISA检测小鼠24 h尿蛋白,PAS染色观察小鼠肾组织病理改变,免疫组织化学检测IV型胶原以及纤连蛋白(fibronectin,FN)在肾组织的表达,Western印迹检测磷酸化的信号转导与转录激活因子3(signal transducer and activator of transcription 3,STAT3)及IκB在肾组织的表达。结果:与db/m小鼠比较,db/db小鼠体型肥胖,血糖明显升高,伴有大量蛋白尿;病理改变为肾小球肥大,系膜区扩张,基膜增厚,细胞外基质(extracellular matrix,ECM)合成增加;Western印迹检测肾组织中磷酸化的STAT3表达增加,IκB表达减少。与db/db小鼠比较,姜黄素治疗后明显降低db/db小鼠24 h尿蛋白,减少肾组织中IV型胶原以及FN的表达,抑制STAT3磷酸化及IκB降解。结论:姜黄素可以减少2型糖尿病模型db/db小鼠的蛋白尿,减轻肾小球硬化,其作用机制可能与抑制STAT3磷酸化及IκB降解有关。

雷公藤甲素治疗db／db糖尿病小鼠的疗效观察

目的:利用db/db小鼠验证雷公藤甲素对糖尿病肾脏损伤的治疗作用,探讨雷公藤甲素防治糖尿病肾病的机制。方法:9周龄的db/db和db/m小鼠分为五组:(1)db/m正常对照组;(2)db/db糖尿病对照组;(3)缬沙坦治疗组;(4)雷公藤甲素低剂量治疗组;(5)雷公藤甲素高剂量治疗组。于4周、8周及12周测定各组24h尿白蛋白、血生化和体重。光镜观察肾小球病变,电镜观察足突改变,并作定量分析。免疫病理观察足细胞裂孔膜蛋白nephrin,足细胞损伤标志物desmin,炎症反应标志物单核细胞趋化蛋白1(MCP-1),氧化应激标志物4羟壬烯醛(4-HNE)的表达。结果:db/db小鼠经雷公藤甲素治疗后蛋白尿下降,肾小球肥大和足细胞损伤减轻,肾组织炎症和氧化应激状态改善,同时高血脂和肥胖减轻。该作用随治疗时间延长,效果更加明显,且高剂量疗效优于低剂量。雷公藤甲素降低蛋白尿、改善肾小球肥大的作用与缬沙坦相似,但降低肾组织炎症和氧化应激的作用雷公藤甲素比缬沙坦更强。结论:雷公藤甲素能明显降低db/db小鼠尿蛋白的排泄,减轻肾组织炎症反应,改善肾脏组织病变,对糖尿病肾脏损伤具有显著且更全面的治疗作用。