小檗碱改善高脂饮食大鼠的胰岛素抵抗

目的:观察小檗碱是否能改善高脂饮食诱导的胰岛素抵抗,以探讨小檗碱干预糖耐量受损(IGT)的可能性。方法:8周龄雄性SD大鼠29只,分为正常组(NC,n=9)和高脂组(HF,n=20)。高脂饲料喂养14周后高脂组分为二组,10只大鼠继续喂养高脂饮食,另一小檗碱组(HF B,n=10)每天灌胃小檗碱150mg/kg体重,治疗6周后进行口服葡萄糖耐量试验和胰岛素耐量试验(ITT),评估小檗碱对胰岛素敏感性的影响。结果:HF组大鼠体重、肝重和附睾脂肪重量均明显高于HF B和NC组(均P<0.01),HF B组空腹血糖和葡萄糖负荷后2h血糖明显低于HF组(分别为5.70±0.52mmol/Lvs6.66±0.51mmol/L和7.88±0.46mmol/Lvs8.85±1.01mmol/L),空腹和葡萄糖负荷后2h胰岛素HF B组也显著低于HF组(分别为0.63±0.25ng/mlvs1.64±0.68ng/ml和1.20±0.21ng/mlvs3.60±0.36ng/ml)。各时间点血糖和胰岛素HF组均显著高于NC组(均P<0.01)。Homa胰岛素抵抗指数HF组明显高于HF B组(P<0.01)。ITT腹腔注射胰岛素后各时间点血糖下降幅度HF B组均高于HF组,15min时HF B组血糖下降23%,而HF组仅下降7%。结论:长期高脂饮食可导致大鼠胰岛素抵抗,小檗碱明显降低高脂大鼠的高胰岛素血症,改善胰岛素抵抗,因此适合于IGT的干预。     

瘦素、胰岛素抵抗与体脂分布

瘦素是ob基因的产物,它除增加能量消耗、减少食物摄入和降低脂肪贮存外,还与生殖、血压调节、血细胞增殖等密切相关;此外,瘦素与胰岛素之间有双向作用,形成脂肪-胰岛内分泌轴,一旦此轴的反馈机制破坏,则可能导致肥胖、高胰岛素血症及2型糖尿病.瘦素与体脂含量密切相关,特别是与皮下脂肪呈显著正相关.     

高脂饮食诱发肥胖大鼠胰腺结构变化及其与糖尿病的关系

目的：观察高脂饮食诱发肥胖大鼠胰腺的结构变化,并探讨其与糖尿病的关系。方法：选用出生21 d雄性SD大鼠,经高脂饲料喂养,衡量其肥胖程度,检测血糖、胰岛素和C-肽水平,光镜和透射电镜观察胰组织等变化。结果：经高脂饮食诱发的肥胖大鼠,血糖、胰岛素光子数均高于对照组,血C-肽光子数与对照组差别不显著;肥胖大鼠的胰腺腺泡间或小叶间,出现脂肪细胞堆积,淋巴细胞浸润和结缔组织纤维增生;某些腺泡和胰岛细胞出现脂肪或空泡样变性。结论：高脂饮食可诱发大鼠肥胖,并出现血糖、胰岛素水平和胰组织结构的变化;该变化可能与胰组织通道阻塞、胰淋巴回流障碍、胰岛素等多肽激素转运异常有关。     

瘦素、脂联素与妊娠期糖尿病胰岛素抵抗关系的研究

目的探讨瘦素、脂联素与妊娠期糖尿病胰岛素抵抗的关系。方法采用稳态模型评估法评估正常糖耐量孕妇（NGT）糖耐量减低孕妇（GIGT）和妊娠期糖尿病孕妇（GDM）的胰岛素抵抗指数,采用放射免疫分析方法检测其血浆瘦素、脂联素、血糖及胰岛素水平。结果 GDM组和GIGT组HOMA-IR显著高于NGT组,GDM组HOMA-IR显著高于GIGT组。血清瘦素水平由NGT组到GIGT组和GDM组呈显著增高,瘦素与空腹胰岛素、孕晚期体重指数、HOMA-IR呈显著正相关;血清脂联素由NGT组到GIGT组和GDM组呈显著下降,脂联素与空腹胰岛素、孕晚期体重指数、HOMA-IR呈显著负相关。结论瘦素、脂联素水平与GDM患者IR程度密切相关,其水平可作为预测妊娠期糖尿病胰岛素敏感性的指标,将来可能是治疗妊娠期糖尿病的新靶点。     

高脂饮食诱导胰岛素抵抗小鼠胰岛IRc/IRS-1低表达

目的:观察高脂饮食诱导的胰岛素抵抗模型小鼠胰岛上胰岛素受体(IRc)/胰岛素受体底物-1(IRS-1)表达的变化。方法:20只雄性昆明小鼠随机分为高脂饲料模型组和普通饲料对照组,每组各10只。喂养20周后,观察两组小鼠大体情况,称量体重(BW),酶法测空腹血糖(FBG),酶联免疫法测空腹胰岛素(FIns)浓度,计算胰岛素抵抗指数(HOMA-IR);HE染色观察胰岛组织学变化;免疫组织化学染色分析胰岛IRc/IRS-1的表达。比较两组各检测指标的统计学差异。结果:模型组FBG、HOMA-IR明显高于对照组(P均0.01);胰岛边界欠完整,内部结构紊乱,伴炎性细胞浸润;IRc/IRS-1的表达较对照组明显降低(P均0.05)。结论:高脂饮食可成功诱导小鼠外周胰岛素抵抗,且胰岛上IRc/IRS-1的表达降低。     

厚朴酚对高脂饮食性肥胖大鼠体重及胰岛素抵抗的影响

目的 观察厚朴酚对高脂饮食性肥胖大鼠体重和血清生化指标的影响,并探讨其机制.方法 将SD大鼠随机分成4组:对照组,高脂组和厚朴酚高、低二个剂量组.每天定时称量食水、灌胃,每周测体重,第8周末各组大鼠禁食12 hA股动脉取血测定血清生化指标.结果 低剂量厚朴酚组从第4周开始体重比高脂组显著降低(P＜0.05),高、低剂量厚朴酚组的胰岛素、游离脂肪酸、丙二醛以及低剂量组的血糖、三酰甘油比高脂组都显著下降(P＜0.05).结论 厚朴酚能降低高脂饮食性肥胖大鼠的体重,并对胰岛素抵抗和糖脂代谢紊乱等有一定的改善作用.     

高脂饲料诱导的大鼠胰岛素抵抗及其与血清瘦素的关系

摄入大量脂肪被认为是胰岛素抵抗（insulin resistance,IR)形成的一个主要因素，本工作根据Storlien LH的配方制作高脂饲料，分别喂饲成年雄性SD大鼠30d和／或60d，用Kraegen EW方法建立正糖钳技术评估IR，观察IR形成和发展过程中基础血清瘦素和胰岛素刺激下血清瘦素的变化。结果喂饲大鼠高脂饲料30d形成IR，其血糖，血清瘦素水平，肩胛区脂肪、肾周脂肪、附睾脂肪垫重量均较对照组显著升高（均P＜0．01），但血清胰岛素水平与对照组比较无差别；喂饲大鼠高脂饲料60d,IR程度和高血糖水平与30d高脂组仍一样，血清瘦素水平和三处脂肪重量进一步升高（P＜0．001和0．01），出现高胰岛素血症（P＜0．05）；但喂饲高脂30和60天动物体重增长和正糖钳实验中灌流胰岛素2h后的血清瘦素水平与对照组无差别。结果：提示高脂饲料可诱导正常成年大鼠形成IR，体脂增高，高血糖，高瘦素血症是这类IR大鼠的特征，而高瘦素血症可能是IR形成的原因，而高胰岛素血症是IR的结果。     

高脂饮食诱导胰岛素抵抗小鼠血浆microRNA 表达谱及其与TLR4 的关系

目的:筛选高脂饮食诱导的胰岛素抵抗小鼠,以及应用Toll 样受体4(Toll-like receptor4,TLR4)抑制剂TAK-242 干预的胰岛素抵抗小鼠血浆差异表达的微小RNA(microRNA,miRNA),探讨胰岛素抵抗、TLR4 和差异表达miRNAs 的关系。方法:血浆标本来自前期实验的3 组小鼠,即以普通基础饲料喂养(Low fat diet,LFD)的正常对照组、给予TAK-242 的高脂饮食组(Treated high fat diet,HFD-T)和单纯高脂饮食组HFD-C,应用小鼠miRNA 芯片检测血浆miRNA 表达谱,筛选差异表达的miRNAs;采用实时荧光定量PCR 方法验证芯片结果。应用生物信息学方法,以TLR4 及其信号传导通路为中心,预测差异表达miRNAs 的靶基因,并对靶基因分别进行GO 和KEGG 富集分析,以判定差异miRNAs 主要影响的生物学功能或者通路。结果:miRNA 基因芯片筛查结果显示,单纯高脂饮食组与正常饮食组比对,筛选出差异显著的miRNAs 共计185 种,其中6 种miRNAs 表达上调,179 种miRANs 表达下调;给予TAK-242 的高脂饮食组与正常饮食组比对,筛选出差异显著的miRANs共计171 种,均表达下调;给予TAK-242 的高脂饮食组与单纯高脂饮食组比对,筛选出差异表达的miRNAs 共计13 种,均为下调。生物信息学分析结果显示,以TLR4 为中心挖掘与其互作的蛋白质,共发现有10 种蛋白;在TAK-242 给予的高脂饮食组与单纯高脂饮食组中差异表达倍数均在1 000 以上的4 种miRNAs (mmu-miR-3095-3p、mmu-miR-5113、mmu-miR-709 和mmu-miR-335-3p),可在TLR4 的互作蛋白质或Toll 样受体信号通路中找到其作用的靶基因,发现这些靶基因74% 属于生物过程基因,其中转录调控因子占82%。实时荧光定量PCR 检测mmu-miR-3095-3p、mmu-miR-5113、mmu-miR-709 和mmu-miR鄄335鄄3p水平,变化趋势与芯片结果一致。结论:胰岛素抵抗发生时,血浆miRNAs 表达谱存在改变,此变化与TLR4 及其信号通路相关。该研究结果丰富了胰岛素抵抗发生的机制,为寻找胰岛素抵抗血浆miRNAs 诊断标志物提供了实验依据。     

高脂饲养致小鼠胰岛素抵抗对脂肪肝形成的影响

目的:探讨高脂饲养致小鼠脂肪肝形成的机制。方法:随机将8周雄性C57BL/6J小鼠分成高脂饲养组(给予含60%卡路里的高饱和脂肪酸饲养)和正常对照组,饲养12周。监测体重、肝重、血甘油三酯、血总胆固醇、血糖和血胰岛素水平,通过高胰岛素正葡萄糖钳夹实验反映胰岛素敏感性,HE染色、苏丹IV染色及肝脂含量反映肝组织脂质沉积情况,确定高脂饲养致小鼠脂肪肝的形成。通过Western blot法检测磷酸化胰岛素受体底物1(IRS1)和蛋白激酶B(Akt)水平反映胰岛素信号通路激活情况,检测固醇调节元件结合蛋白1(SREBP-1)和脂肪酸合成酶(FAS)蛋白水平反映肝内脂质合成的情况。结果:高脂饲养组小鼠体重及肝重较正常对照组小鼠明显增加。与正常对照组相比,高脂组血和肝组织内甘油三酯和总胆固醇含量显著升高,血清胰岛素水平升高,葡萄糖输注率减少,磷酸化IRS1和Akt水平降低。肝组织HE染色可见高脂组肝细胞胞浆内充满大量脂肪空泡,苏丹IV染色可见肝细胞内存在大量大小不一的红色脂滴;SREBP-1和FAS蛋白水平明显升高。给予外源性油酸干预原代正常肝细胞48 h,磷酸化IRS1和Akt水平呈浓度依赖性减低,而SREBP-1和FAS蛋白表达明显升高。结论:高脂饲养导致小鼠肝脏发生胰岛素抵抗,并通过激活SREBP-FAS脂肪合成途径,促进肝脏脂质沉积,从而诱发脂肪肝。     

谷氨酰胺对高脂饮食诱导C57BL/6J小鼠肥胖和胰岛素抵抗的影响

目的:探讨谷氨酰胺(L-glutamine,Gln)对高脂饮食(high-fat diet,HFD)诱导小鼠肥胖和胰岛素抵抗的影响。方法:60只雄性C57BL/6J小鼠随机分为正常对照(normal control,NC)组、HFD组、HFD+丙氨酸(Lalanine,Ala)组和HFD+Gln组,每组15只。每周记录小鼠体重,给药16周后禁食不禁水12 h测定空腹血糖(fasting blood glucose,FBG),处死后剖腹取附睾脂肪垫并称重。采用酶联免疫法检测小鼠胰岛素(insulin,INS)、瘦素(leptin,LEP)、脂联素(adiponectin,APN)和胰高血糖素样肽1(glucagon-like peptide-1,GLP-1)的水平,并计算胰岛素抵抗指数(insulin resistance index,IRI)和胰岛素敏感指数(insulin sensitivity index,ISI)。结果:与NC组比较,HFD组小鼠体重和附睾脂肪垫重量明显升高,FBG、INS、IRI和LEP水平均明显升高,ISI和APN水平明显降低(P0.05);与HFD组比较,HFD+Gln组小鼠体重明显下降,FBG和LEP水平明显降低,IRI明显减小(P0.05)。4组小鼠血清的GLP-1水平差异无统计学显著性。结论:谷氨酰胺减轻高脂饮食诱导的肥胖小鼠体重和胰岛素抵抗。     

Serum leptin levels in gastric cancer patients and the relationship with insulin resistance

Introduction

Serum leptin levels have been examined in various cancers, with conflicting results. However, there is limited information regarding serum leptin levels and insulin resistance in gastric cancer patients. Therefore, we aimed to investigate serum leptin levels, performance status, insulin levels and insulin resistance in patients with gastric cancer. In addition, we examined the relationship between these measurements and leptin levels.

Material and methods

Thirty-nine patients with gastric cancer and 30 control subjects were enrolled in the study. Serum leptin, total protein, albumin, growth hormone, insulin and glucose levels were measured. The homeostasis model assessment (HOMA) was used to assess insulin resistance.

Results

Serum levels of insulin, glucose and growth hormone and insulin resistance were significantly lower in gastric cancer patients than controls (p < 0.05 for all). In the Pearson correlation analysis, insulin resistance was found to be significantly correlated with serum leptin levels in gastric cancer patients (r = 0.320, p = 0.047). We observed a significant negative correlation between performance status and insulin resistance in patients with cachexia (r = –0.512, p = 0.030), while no association was found in non-cachectic patients.

Conclusions

We concluded that serum leptin levels are significantly lower in gastric cancer patients. In addition, gastric cancer patients have decreases in insulin levels, insulin resistance and growth hormone levels. This study found a positive association between serum leptin levels and insulin resistance. Moreover, there is a negative association between serum leptin levels and growth hormone levels. Thus, low insulin and growth hormone levels may suppress the production of leptin in gastric cancer patients.     

The acute effects of insulin on the cardiorespiratory responses to hypoxia in streptozotocin‐induced diabetic rats

Aims: We examined whether or not streptozotocin (STZ)‐induced diabetic rats, which have a lower heart rate (HR, beats min^?1) than control rats, could maintain hypoxic ventilatory response. Methods: Twenty‐six Wistar rats, which had been injected with STZ (60 mg kg^?1, EXP) or vehicle (0.1 m citrate buffer, CONT) intraperitoneally at 9 weeks of age, had their cardiorespiratory responses to normoxia and 12%O₂ examined after 5 weeks. Results: Compared with CONT rats, EXP rats had a higher blood glucose [24 ± 3 vs. 5 ± 1 (mean ± SD) mmol L^?1], a lower body weight (320 ± 23 vs. 432 ± 24 g), lower HR (303 ± 49 vs. 380 ± 44 in normoxia, and 343 ± 56 vs. 443 ± 60 in hypoxia) and a lower mean arterial blood pressure (MAP) (89 ± 6 vs. 102 ± 10 mmHg in hypoxia). In contrast, both groups had similar values in ventilation (), –metabolic rate (MR) ratio and arterial blood gases (ABGs). In EXP rats, with an acute insulin supplement (i.v., 0.75 U h^?1 for 1.5–2 h), not only blood glucose, but also HR, and MAP were normalized as those obtained in CONT rats, and in hypoxia further increased without affecting –MR ratio and ABGs. Such acute cardiorespiratory stimulating effects of insulin could not be obtained in non‐diabetic rats (n = 7, 355 ± 24 g), in which euglycaemia (mean 6.4 mmol L^?1) was maintained during the measurements. Conclusions: Our results suggest that, in STZ‐induced diabetic rats: (1) ventilation is hardly suppressed by hyperglycaemia, (2) cardiorespiratory responses can be acutely stimulated by short insulin injection, and (3) the effects, including those through acute blood glucose normalization, are possibly specific for the diabetic impairments.     

Plasma leptin and insulin in C57Bl/6J mice on a high-fat diet: relation to subsequent changes in body weight

It has been proposed that leptin and insulin through central effects are involved in the regulation of energy balance and body weight. Whether circulating leptin or insulin levels predict subsequent changes in body weight is, however, not known. We examined plasma leptin and insulin at 2, 3, 6, 9 and 12 months of age in C57Bl/6J mice given a normal diet (n = 12) or a high-fat diet (58% fat on a caloric base; n = 15). Plasma leptin levels increased by age and correlated with body weight in the entire material (r = 0.81, P < 0.001). Also plasma insulin increased by high-fat diet and correlated across all age periods with body weight (r = 0.56, P < 0.001). In mice, given normal diet, plasma leptin or insulin did not correlate to subsequent changes in body weight at any of the time points studied. However, in mice given the high-fat diet, plasma leptin at 6 (r = ?0.57, P = 0.027) and 9 months of age (r = ?0.56, P = 0.042) as well as plasma insulin at 6 (r = ? 0.51, P = 0.049) and 9 months (r = ?0.58, P = 0.037) correlated inversely to the change in body weight during the subsequent 3-month period. Hence, both leptin and insulin are negative predictors for future weight gain in high-fat fed mice. This suggests that when the regulation of body weight is challenged by a high-fat diet, leptin and insulin act to restrain or prevent future weight gain. This in turn may suggest that impairment of these (probably central) actions of leptin and insulin might underlie excessive increase in body weight under such conditions.     

Plasma insulin and the time pattern of feeding in the rat

Blood levels of glucose and insulin during meals and between-meal-intervals were measured in virtually undisturbed rats. After a peak due to glucose absorbed from the meal blood sugar soon reverts to the pre-meal level. Insulin shows a similar peak followed by a continuing decline so that just before the next meal it is lower than at any other time. In terms of the glucostatic theory this might mean that meals are triggered by a critical drop of insulin. However, intravenous infusions of glucose, resulting in continously high insulin, do not affect timing or size of meals. Glucostatic factors probably are of minor importance in meal-to-meal regulation in the rat. However, they may subserve nutritional homeostasis on at least two other points.     

Neonatal exposure to leptin reduces glucose tolerance in adult mice

Aim: The aim of this study was to evaluate the effect of leptin treatment in mouse neonates on glucose metabolism in adulthood. Methods: Leptin was administered subcutaneously to normally nourished neonates, from 5.5 to 10.5 days of age, to mimic the premature surge observed in neonates undernourished in utero. At 15–16 weeks of age, we measured blood glucose or insulin levels after the intraperitoneal administration of glucose or insulin. Results: After the intraperitoneal administration of glucose, the levels of blood glucose, but not insulin, in adult mice that received the neonatal leptin treatment were significantly higher than that of those which received vehicle control. After the intraperitoneal administration of insulin, the levels of blood glucose in adult mice that underwent neonatal leptin treatment were significantly higher than that of those which received vehicle control. Conclusion: These findings suggest that the premature leptin surge plays an essential role, as a programming signal during the early neonatal period, as well as in the developmental origins of impaired insulin sensitivity.     

糖尿病非酒精性脂肪肝病大鼠肝组织胰岛素受体、瘦素受体 mRNA的表达

目的：观察2型糖尿病大鼠肝脏的病理变化,探讨肝组织胰岛素受体（insulin R）、瘦素受体（leptin R）mRNA表达在糖尿病性非酒精性脂肪肝病（NAFLD）发病机制中的作用。方法：SD大鼠随机分成2组：正常组与2型糖尿病组。2型糖尿病组在以高脂饮食4周后,加小剂量(30 mg/kg)链脲佐菌素（STZ）诱导2型糖尿病性非酒精性脂肪性肝病大鼠模型,继续给予高脂饮食12周。分别采用HE染色、苏丹Ⅲ染色、Masson染色光镜下观察肝脏组织的病理改变;透射电镜观察肝脏超微结构改变;生化法检测血糖、血甘油三酯（TG）、血总胆固醇（TC）、丙氨酸转氨酶（ALT）和天门冬氨酸转氨酶（AST）水平;放免法检测血清胰岛素水平;ELISA法检测血清瘦素水平;RT-PCR法检测肝组织磷酸烯醇式丙酮酸羧激酶（PEPCK）、葡萄糖-6-磷酸酶（G6Pase）、insulin R、leptin R mRNA表达水平。结果：糖尿病大鼠肝细胞明显脂肪变性、碎片状坏死伴炎细胞浸润及肝纤维化病变,电镜下主要表现为肝细胞核固缩,胞浆内含大量脂滴,狄氏间隙胶原纤维增生;血糖、血胰岛素、TG、ALT、AST水平明显升高（P<0.01）,TC水平升高(P<0.05）,血清瘦素水平明显下降（P<0.01）;肝组织insulin R、leptin R mRNA表达显著升高（P<0.01）,PEPCK、G6Pase mRNA表达无显著变化。结论：2型糖尿病时的胰岛素抵抗是NAFLD发生的根源,由于胰岛素抵抗而致的低血清瘦素水平、肝组织insulin R、leptin R 表达上调参与了NAFLD的发生。     

肥胖儿童血清高敏C反应蛋白、瘦素、可溶性瘦素受体和胰岛素的水平及意义

目的探讨肥胖儿童血清高敏C反应蛋白、瘦素、可溶性瘦素受体及胰岛素的水平变化及临床意义。方法对64例12岁肥胖儿童进行血清高敏C反应蛋白（high-sensitivity C-reactive pro-tein,hs-CRP）、瘦素（leptin,Lp）、可溶性瘦素受体（soluble leptin receptor,sLR）及胰岛素（Insulin,INS）的水平测定,与48例健康体检儿童进行对照比较。其中,血清Lp、INS采用放射免疫分析法（RIA）测定,sLR采用酶联免疫吸附试验法检测,hs-CRP采用电化学发光免疫法测定。结果肥胖儿童组血清hs-CRP、Lp、INS水平及BMI均显著高于对照组（均P〈0.01）,sLR水平低于对照组（P〈0.05）;相关性分析显示肥胖儿童血清hs-CRP水平与Lp、INS、BMI之间均呈显著性正相关性（r=0.575,P〈0.01;r=0.504,P〈0.01;r=0.685,P〈0.01）,与sLR呈显著性负相关性（r=-0.339,P〈0.01）;Lp与INS、BMI之间呈显著性正相关性（r=0.352,P〈0.01;r=0.503,P〈0.01）,与sLR呈显著性负相关性（r=-0.467,P〈0.01）,sLR与BMI呈显著性负相关性（r=-0.398,P〈0.01）。结论肥胖儿童已存在炎症状态的改变及瘦素、胰岛素抵抗,且三方面密切相关。对这些血清学指标的检测,有助于儿童肥胖状态的监控和治疗。     

血清瘦素及胰岛素和血糖测定在妊娠期糖代谢中的临床意义

目的:探讨血清瘦素及胰岛素和血糖水平与妊娠期糖代谢异常孕妇的关系。方法:采用放射免疫分析测定36例妊娠期糖代谢异常孕妇(糖代谢异常组)和34例正常孕妇(正常妊娠组)的空腹及口服50g葡萄糖后3h的血清瘦素水平;采用电化学发光法测定两组孕妇的空腹血清胰岛素水平;采用葡萄糖氧化酶法测定两组孕妇的口服50g葡萄糖后1h的血糖水平。结果:1.糖代谢异常组孕妇血清瘦素水平为(14.9±4.3)μg/L,正常妊娠组为(9.8±1.7)μg/L,两组比较差异有显著性(P<0.01);2.糖代谢异常组孕妇空腹血清胰岛素、服糖后1h血糖水平分别为(12.9±4.3)mU/L、(11.0±1.4)mmol/L;正常妊娠组孕妇分别为(8.45±3.0)mU/L、(7.84±1.3)mmol/L。糖代谢异常组孕妇血清瘦素水平与空腹血清胰岛素、服糖后1h的血糖水平呈明显的正相关关系。相关系数(r)分别为0.835、0.758。结论:空腹血清瘦素水平升高见于妊娠期糖代谢异常孕妇,其瘦素水平的高低与空腹胰岛素及血糖水平相关。     

N-乙酰半胱氨酸改善高游离脂肪酸所致大鼠外周胰岛素抵抗

目的 探讨N-乙酰半胱氨酸(NAC)对高游离脂肪酸(FFA)导致的外周胰岛素抵抗的影响及机制.方法 SD大鼠随机分为对照组(NS组,12只)、脂肪乳输注组(FFA组,13只)和脂肪乳 NAC组(NAC组,12只).输注48 h,(1)测血浆硝基酪氨酸,丙二醛(MDA)和还原型谷胱甘肽(GSH)水平;(2)高胰岛素正糖钳夹试验,评价外周胰岛素抵抗程度;(3)实时荧光定量PCR方法测定肌肉组织胰岛素受体底物-1(IRS-1)、胰岛素受体底物-2(IRS-2)mRNA表达.结果 (1)FFA组硝基酪氨酸,MDA高于NS组,GSH低于NS组,NAC分别改善28.6%,33.1%,22.9%(P＜0.05);(2)FFA组葡萄糖输注率(GIR)比NS组降低(P＜0.05),用NAC后GIR升高36.6%(P＜0.05);(3)FFA组肌肉组织IRS-1、IRS-2 mRNA表达比NS组降低87.7%、50.7%(P＜0.05);NAC组肌肉组织IRS-1、IRS-2表达比FFA组增加370.1%、46.2%,(P＜0.05).结论 NAC干预能改善高FFA所致的外周胰岛素信号传导障碍,逆转外周胰岛素抵抗,可能与NAC纠正机体氧化及抗氧化失衡有关.