瘦素及其受体在食管鳞癌中的表达意义

目的 探讨瘦素(leptin)及其受体(Ob- Ra、Ob-Rb)与食管鳞癌的关系,为食管鳞癌的发病机制研究提供一定的理论依据.方法 RT- PCR法检测20例正常食管和24例食管鳞癌组织中leptin、Ob-Ra、Ob- Rb的mRNA表达.结果 (1)20例正常食管组织中leptin、Ob- Ra、Ob-Rb的mRNA表达阳性率分别为50.0％、50.0％、40.0％;24例食管鳞癌组织中leptin、Ob- Ra、Ob-Rb的mRNA表达阳性率分别为79.2％、83.3％、83.3％.正常食管组与食管鳞癌组相比差异均有统计学意义(P＜0.05).(2)食管鳞癌组织中leptin、Ob-Ra、Ob-Rb的mRNA相对表达量亦高于正常食管组织,差异均有统计学意义(P＜0.05).结论 瘦素及其受体在食管鳞癌组织中的表达阳性率和相对表达量均高于正常食管组织,提示瘦素及其受体可能在食管鳞癌的发生发展中发挥重要作用.     

脑源性多器官功能障碍综合征模型血清内毒素及其受体基因表达

目的探讨急性前脑缺血致多器官功能障碍综合征(MODS)模型血清内毒素含量及其受体在各脏器基因表达的规律,分析脑原性多器官功能障碍综合征(CMODS)的发生机制。方法随机将54只Wistar大鼠分为正常对照组(6只)、假手术组(8只)和前脑缺血组(40只),后者又被随机分为12h、24h、36h、48h、和72h时相点的5个亚组,每亚组各8只;建立大鼠急性前脑缺血模型;分别采用偶氮显色法鲎试验定量法测定血清内毒素和原位杂交技术测定肺、肝、肠和肾组织CD14mRNA水平;使用CMIA真彩色医学图像分析系统,检测CD14mRNA的相对含量。结果大鼠急性前脑缺血后12h血清内毒素升高(0184±0055)Eu/L,24h达高峰(0639±0064)Eu/L,72h基本恢复至正常水平(0117±0024)Eu/L;肺、肝、肠和肾组织CD14mRNA的表达也在缺血后12h升高,24~36h达高峰,48h后下降,并以肺脏变化最显著(P<0001);正常对照组和假手术组CD14mRNA在各脏器均有不同程度的表达,其中两组肺脏的表达有显著性差异(P<001)。内毒素与其受体在各脏器的表达均存在显著相关性(均为P<001),其中与肠、肺组织CDmRNA表达相关最显著(P<0001)。结论急性前脑缺血致MODS大鼠存在内毒素血症;急性脑血管病→应激反应→肠道黏膜屏障损害→内毒素易位→内毒素血症→内脏器官功能障碍→MODS是CMODS发生的     

地塞米松对HepG2细胞OB-Ra及OB-Rb mRNA表达的调节

观察不同浓度的地塞米松对HepG2细胞内瘦素受体mRNA表达的影响 ,发现地塞米松对瘦素短型受体 (OB Ra)及长型受体 (OB Rb)的mRNA表达均有增强性调节作用。     

长胞内域瘦素受体全长mRNA表达增加对骨胳肌细胞葡萄糖氧化的影响

目的 观察增加骨胳肌细胞全长长胞内域瘦素受体(OBRb)mRNA表达以后,瘦素对原代培养的骨胳肌细胞葡萄糖氧化代谢的影响。方法 分离SD乳鼠的骨胳肌细胞,分4组进行细胞培养,其中转染重组质粒、转染空载质粒和非转染3组(分别加瘦素10ng/ml和胰岛素10mU/ml),另外1组为非转染未加瘦素和胰岛素的对照组。将载有全长OBRb cDNA的真核表达质粒或空载质粒在脂质体的介导下导入骨胳肌细胞。48h后加入瘦素和胰岛素,孵育1h,再加入D-[U-~(14)C]-葡萄糖,继续培养2h后终止反应,收集~(14)CO_2,液体闪烁计数。同时以RT-PCR检测转染细胞的OBRb mRNA表达水平。结果 重组质粒转染、空载质粒转染和非转染3组,特异性条带和β-actin条带积分光密度比值分别为1.22±0.10、0.41±0.08和0.49±0.09,前者较其它两组明显升高(均P<0.001)。葡萄糖氧化前者明显高于其他3组(均P<0.005)。结论 增加SD乳鼠骨胳肌细胞OBRb mRNA的表达,明显改善细胞葡萄糖氧化,提示OBRbmRNA的高度表达能改善瘦素的作用。     

芍药甙对急性坏死性胰腺炎大鼠NF-kB p65及细胞因子表达的影响

目的 观察芍药甙对ANP大鼠的治疗效果及对NF-kB、TNF-α、IL-6表达的影响.方法 40只大鼠随机分为正常组、ANP24h、72h组和芍药甙24h、72h治疗组(芍药组),每组8只.采用L-精氨酸腹腔内注射法诱发ANP模型,芍药组于造模后即刻用2ml芍药液灌胃,11次/2h.各组采血检测血清淀粉酶,取胰腺组织行病理检查,Western blot 法检测 NF-kB p65蛋白表达,实时荧光定量PCR法检测TNF-α mRNA\IL-6 mRNA的表达.结果 造模后24h ANP组和芍药血清淀粉酶分别为(3569±516)U/L和(2994±370)U/L,明显高于正常组的(1136±107)U/L(P＜0.05);病理学分值分别为4.25±0.63和3.06±0.46,也明显高于正常组的0分(P＜0.05);芍药组24h的NF-kB p65蛋白及TNF-αmRNA、IL-6 mRNA表达相对值分别为0.230±0.0440.141±0.018和0.017±0.029,72h分别为0.040±0.006、0.078±0.017和0.008±0.001,均显著低于同时间点的ANP组(P＜0.05).结论芍药甙能减轻ANP大鼠胰的病理损害程度,其机制可能与抑制NF-kB活化、抑制TNF-α mRNA、IL-6 mRNA表达有关.     

糖基化终产物对单核细胞源性巨噬细胞过氧化物酶体增殖物激活型受体γ表达的影响

目的研究糖基化终产物(AGEs)对单核细胞源性巨噬细胞过氧化物酶体增殖物激活型受体γ(PPARγ)表达的影响。方法将AGEs-牛血清白蛋白(AGEs-BSA)与佛波酯(PMA)诱导分化72h后的巨噬细胞共同孵育,按加入AGEs-BSA的浓度不同分为A组(50mg/L)、B组(100mg/L)、C组(200mg/L)、D组(400mg/L),另外仅加100mg/L BSA的为对照组,各组分别处理细胞24h,另用200mg/L AGEs-BSA分别于0、12、24、36和48h时处理细胞,运用RT-PCR和Western blot方法检测细胞PPARγmRNA和蛋白的表达。结果细胞PPARγmRNA和蛋白的表达量A组为0.727±0.041和1.260±0.033、B组0.655±0.029和1.059±0.047、C组0.527±0.032和0.899±0.036、D组0.353±0.026和0.415±0.025;较对照组明显降低(P<0.05)。不同时相点作用下,细胞PPARγmRNA和蛋白表达量12h为0.918±0.048和2.830±0.063、24h为0.718±0.023和1.288±0.006、36h为0.567±0.028和0.876±0.037、48h为0.367±0.019和0.455±0.009;较0h时相点比较明显降低(P<0.05)。结论AGEs可抑制单核细胞源性巨噬细胞PPARγmRNA和蛋白的表达,呈浓度和时间依赖性。     

辛伐他汀对老年冠状动脉支架植入术的不稳定性心绞痛患者血清瘦素水平的影响

目的探讨瘦素在老年PTCA的UAP患者中的作用及辛伐他汀对其影响。方法采用酶联免疫法测定老年UAP患者及PTCA后6、24、48 h及辛伐他汀治疗15 d后血清瘦素水平。结果老年UAP患者血清瘦素水平明显高于对照组〔(19.21±8.33),(9.39±4.02);P<0.05〕,PTCA后6、24、48 h血清瘦素水平明显高于非PTCA组〔(33.45±10.93),(23.52±11.18);(31.86±13.12),(24.85±10.89);(25.37±10.09),(19.88±11.12);P<0.05)〕。辛伐他汀治疗后15 d老年UAP患者血清瘦素水平明显低于治疗前〔(13.07±9.72),(19.21±8.33);P<0.05)〕。结论瘦素参与了老年UAP病理过程,PTCA后给予相应治疗以降低瘦素水平是必要的,辛伐他汀可逆转老年UAP血清瘦素的变化。     

缺氧对肝癌HepG2细胞内PPARα和HIF-1α表达的影响及机制探讨

目的 观察不同程度缺氧条件下,肝癌HepG2细胞内过氧化物酶体增殖物激活受体α(PPARα)和缺氧诱导因子1α(HIF-1α)的表达,及反义封闭HIF-1α后对PPARα表达的影响.方法 HepG2细胞分为正常对照组(A组)、缺氧24 h组(B组)、缺氧48 h组(C组)、缺氧72 h组(D组).观察各组的PPARα、HIF-1α蛋白和mRNA表达变化.再设计对照组(E组)、HIF-1α反义寡核苷酸组(F组)、HIF-1α正义寡核苷酸组(G组)、HIF-1α错义寡核苷酸组(H组),观察各组HIF-1α对PPARα的表达影响.结果 正常对照组,PPARα和HIF-1α少量表达.随着缺氧时间延长,PPARα和HIF-1α的表达呈现逐渐升高,在缺氧24 h时,mRNA和蛋白开始增高,48 h增高明显,72 h达高峰.反义封闭HIF-1α后,PPARα表达明显下降.结论 PPARα及HIF-1α的表达随肿瘤细胞缺氧信号的加强而增加,PPARα受HIF-1α的调控.     

去甲肾上腺素对人肝细胞系表达瘦素及瘦素受体的影响

目的探讨交感神经递质去甲肾上腺素(NE)对体外培养人肝细胞系L02表达瘦素及瘦素受体的影响。方法用不同浓度的NE作用于体外培养的人肝细胞系L02,分别于24、48及72 h收集细胞,Western印迹法检测其表达瘦素及瘦素受体蛋白的影响;RT-PCR检测NE对肝细胞系L02瘦素及瘦素受体mRNA的影响。结果①Western印迹结果显示,1、10、100μmol/L NE作用于L02细胞24 h后,瘦素蛋白表达明显高于对照组(1.02±0.08,2.24±0.09,2.35±0.12 vs 0.62±0.09,P<0.05);瘦素受体蛋白表达亦明显高于对照组(1.35±0.13,2.37±0.12,2.39±0.15 vs 0.85±0.13,P<0.05)。②RT-PCR检测L02瘦素以及瘦素受体mRNA的表达情况,1、10、100μmol/L NE作用于L02 24 h后,瘦素mRNA表达明显高于对照组(1.54±0.08,2.37±0.09,2.72±0.12 vs 1.00±0.07,P<0.05);瘦素受体mRNA表达亦明显高于对照组(1.61±0.08,2.27±0.10,3.39±0.11 vs1.00±0.06,P<0.01)。结论交感神经递质NE对体外培养的肝细胞系瘦素以及瘦素受体的表达均有促进作用,从而参与了肝纤维化进程。     

系统性红斑狼疮外周血单个核细胞生长激素受体和mRNA表达的研究

目的　探讨SLE患者外周血单个核细胞 (PBMC)的生长激素受体 (GHR)的表达与系统性红斑狼疮 (SLE)的关系。方法　采用放射性受体配基结合试验 (RLBA)及反转录 聚合酶链反应(RT PCR)研究外周血淋巴细胞GHR变化。结果　SLE活动期患者PBMC的GHR的特异性结合率 (SB) (3 4± 2 0 ) %、总结合率 (TB) (13 8± 5 7) %和静止期患者SB (1 3± 1 2 ) % ,TB (11 4±4 6 ) %均高于正常对照组SB (1 0± 1 0 ) % ,TB (8 3± 0 9) % (P <0 0 1) ;SLE活动期患者PBMC的mRNA的表达水平 (0 77± 0 6 6 )高于静止期患者 (0 4 5± 0 2 8) (P <0 0 5 )和正常对照组PBMC的mRNA的表达 (0 31± 0 2 2 ) (P <0 0 1)。结论　SLE患者PBMC的GHR高表达与SLE的病情活动性相关。     

Pharmacokinetics of human leptin in mice and rhesus monkeys

OBJECTIVE: The pharmacokinetic characteristics of human leptin were examined in rhesus monkeys and in C57BL/6J mice fed a normal chow or a high-fat diet. DESIGN: For the monkey study, in nine rhesus monkeys (body weight 12.4 +/- 2.4 kg; mean +/- s.d.), recombinant met-human leptin was injected intravenously or subcutaneously (1 mg/kg). For the mouse study, after 6 months of feeding C57BL/6J mice a high-fat diet (body weight 32.9 +/- 3.6 g; n = 8) or a control diet (24.5 +/- 1.2 g; n = 6), recombinant met-human leptin was administered intraperitoneally (10 microg/g). Blood samples were collected for leptin measurement at specific time points after leptin administration. MEASUREMENTS: Plasma leptin concentrations were determined by radioimmunoassay and pharmacokinetic analysis was performed. RESULTS: Disposition of human leptin in rhesus monkeys was biphasic following intravenous administration, with a terminal phase half-life of 96.4 +/- 16.5 min and clearance of 1.8 +/- 0.2 ml/min/kg. Subcutaneously administered leptin was absorbed slowly, perhaps by a zero-order process as leptin levels appeared to plateau and remained elevated throughout the 8 h sampling period. In C57BL/6J mice, the absorption and elimination of human leptin were both first-order following intraperitoneal administration. Pharmacokinetic parameters did not differ between normal-weight mice fed a chow diet and obese mice fed a high-fat diet. The elimination half-life was 47.0 +/- 26.4 min in mice fed a high-fat diet and 49.5 +/- 12.0 min in mice fed a control diet. CONCLUSION: The kinetics of leptin in rhesus monkeys were biphasic and clearance was similar to values previously reported in humans. The estimated half-life was 96.4 min in rhesus monkeys and 49.5 min in normal weight mice. The was no difference in leptin kinetics between high-fat fed and control mice, suggesting that the increased baseline leptin levels in the obese mice are due to increased leptin production and secretion.     

e抗原阳性慢性乙型肝炎患者外周血树突状细胞Toll样受体3的表达及意义

目的探讨Toll样受体3（TLR3）的表达与HBV感染后宿主免疫清除障碍的关系。方法选取轻度CHB患者50例,健康对照者48名,其外周血用免疫磁珠细胞分选法获得纯化的CD14^＋单核细胞,用RPMI 1640培养基培养,并且用人粒细胞-巨噬细胞集落刺激因子和hIL-4诱导单核细胞成为未成熟的髓样树突状细胞（mDC）,加入聚肌胞刺激后获得成熟的mDC。分别在剌激后0、12、24、48h用流式细胞仪检测TLR3、CD86、HLA-DR和CD1a的表达,实时PCR检测TLR3的表达变化。结果健康对照组中mDC在刺激后24h,TLR3表达较0 h时上调显著（P〈0.05）,48h时TLR3的表达与0h相比差异无统计学意义（P〉0.05）;患者组在刺激后12、24h TLR3的表达与0h时相比,上调不明显,48h时TLR3的表达显著上调（P〈0.05）。实时PCR检测mDC上TLR3 mRNA结果发现,对照组TLR3 mRNA在刺激后12h的表达水平较0h显著上升（P〈0.05）,也显著高于患者组刺激后0、12、24h的表达水平;患者组刺激后48h的TLR3 mRNA表达水平较0h显著上升（P〈0.05）。与0h比较,健康对照组在刺激后12、24h和48h,CD86的表达水平显著高于患者组（P〈0.05）。患者组与对照组间CD1a和HLA-DR的表达差异无统计学意义。结论慢性HBV感染者mDC受聚肌胞刺激后TLR3表达异常,协同刺激因子CD86表达低下,可能造成宿主对HBV感染的免疫清除障碍,导致疾病慢性化。     

Resting leptin responses to acute and chronic resistance training in type 2 diabetic men and women.

PURPOSE: To evaluate the plasma leptin levels approximately 24 h post-exercise in control and type 2 diabetic subjects and to establish if observed changes in leptin concentrations were acute or chronic effects of a resistance training program. METHODS: Thirty men and women (17 controls and 13 type 2, obese diabetics, age 40-55 y) had resting blood samples drawn at 08:00 h (12 h postprandial) at the beginning of the study (pre-training), 24 h after a three repetition maximal weight lifting bout (acute) and 72 h after their last training bout of 6 weeks of resistance training (chronic). The two groups were not matched with respect to body mass index and the control subjects were not normal weight. Subjects weight-trained three times a week, for 6 weeks, for 1 h, training both the upper and lower body. RESULTS: Serum leptin concentrations were significantly higher in the type 2 diabetics than in the control group at pre-training (41.4+/-8.9 vs 11.4+/-3.0 ng/ml, P<0.05, respectively). Compared to pre-training, the leptin levels decreased significantly (P<0.01) after acute exercise in the diabetics but not in the control subjects (diabetics 30.9+/-7.1 vs controls 10.6+/-2.6 ng/ml). Approximately 72 h after 6 weeks of exercise training, the leptin concentrations were no longer lower than the pre-training values in either group (36.9+/-8.8 vs 11.9+/-8.8 ng/ml, respectively, P=NS). When leptin concentrations were log transformed and adjusted for fat mass there were still significant changes in leptin levels over time and between the control and diabetic group (P<0.05). CONCLUSIONS: The type 2 diabetics showed a significant 30% reduction in resting leptin levels 24 h after a single bout of resistance exercise. This was an acute response to resistance exercise and not a chronic training effect (no difference between pre-training and chronic). The decreased resting leptin concentrations approximately 24 h post-acute exercise may be due to reduced glucose availability to the adipose tissue, particularly in the diabetic subjects. There is no chronic effect of resistance exercise on leptin concentrations.     

Increased expression of hypothalamic leptin receptor and adiponectin accompany resistance to dietary-induced obesity and infertility in female C57BL/6J mice

BACKGROUND: Obesity is strongly associated with female infertility, but the mechanisms underlying this relationship are largely unknown. METHODS: We investigated the effect of increasing dietary fat percentage upon body mass, hypothalamic neuropeptide gene expression, adipose hormone secretion and fertility in females of the inbred mouse strains C57BL/6J and DBA/2J. To assess the effect of obesity independent of dietary influence, we also compared these parameters in wild-type female C57BL/6J mice to those congenic for the obesogenic mutations ob/ob and A(y)/a. RESULTS: After 24 weeks, rather than exhibiting an obese, leptin-resistant phenotype like their female DBA/2J counterparts, wild-type female C57BL/6J mice remained lean, fertile and manifested increased hypothalamic LEPR-B expression. Although both mutant genotypes were associated with obesity and subfertility, ob/ob mice demonstrated significantly increased hypothalamic LEPR-B expression, whereas A(y)/a mice had a significant reduction. Interestingly, wild-type female C57BL/6J mice were noted to manifest significantly higher and lower levels of adiponectin and tissue plasminogen activator inhibitor-1 (tPAI-1), respectively, than weight-matched wild-type female DBA/2J mice. CONCLUSIONS: We conclude that (1) resistance to the obese-infertile phenotype in female C57BL/6J mice is associated with increased hypothalamic leptin receptor expression and alterations in adipokine levels consistent with decreased adipose tissue inflammation and (2) that long-standing hyperleptinemic obesity in mice is associated with a downregulation of the hypothalamic leptin receptor.     

Differential mechanisms and development of leptin resistance in A/J versus C57BL/6J mice during diet-induced obesity

Changes in the biological efficacy of leptin were evaluated in obesity-resistant (A/J) and obesity-prone (C57BL/6J) mice at weaning and after consuming a high-fat (HF) diet for 4 and 8 wk. There was no evidence of leptin resistance in either strain at the start of the study, but after 4 and 8 wk on the HF diet, C57BL/6J mice became unresponsive to ip leptin. C57BL/6J mice responded to intracerebroventricular leptin at these time points but developed peripheral resistance to sympathetic stimulation of retroperitoneal white adipose tissue. In contrast, intracerebroventricular leptin was fully effective in A/J mice, reproducing the complete profile of responses observed in weanling mice. A/J mice were also partially responsive to ip leptin at both time points, increasing uncoupling protein 1 mRNA expression in brown adipose tissue and decreasing leptin mRNA in white adipose tissue. The findings indicate that retention of leptin responsiveness is an important component of the ability of A/J mice to mount a robust adaptive thermogenic response and resist diet-induced obesity.     

Effects of insulin and glucocorticoids on the leptin system are mediated through free leptin

OBJECTIVE: Insulin and glucocorticoids are known to increase total leptin levels. However, the effects of insulin and glucocorticoids on the components of the leptin system - free leptin (FL), bound leptin (BL) and soluble leptin receptor (SR) - have not been elucidated. The aim of this study was to determine if there is a differential effect of insulin and glucocorticoids on the leptin system. MATERIAL AND METHODS: In the first of two studies (study 1), we measured free leptin (FL), bound leptin (BL), a soluble leptin receptor (SR) and insulin, by specific RIA methods, in six healthy subjects on a control day, and subsequently during a hyperinsulinaemic euglycaemic clamp study. In the second study (study 2) we measured the same parameters in six healthy subjects, before (day 1) and during administration of dexamethasone over 3 consecutive days. RESULTS: In study 1, on the control day FL levels rose over the 16 h monitoring period (P = 0.057) and SR levels declined (P < 0.001), but there was no change of BL levels. Even after accounting for diurnal variation, FL levels increased even more substantially over 12 h of insulin infusion than observed on the control day (P < 0.001). In study 2, mean FL concentration doubled from day 1 to day 2 (P = 0.01) and remained elevated subsequently. In contrast to FL, BL and SR levels remained unchanged during the study. Fasting insulin levels (pmol/l) increased from day 1 to day 2, but this rise only approached significance on day 4 (P = 0.05). CONCLUSION: We conclude that insulin and dexamethasone increase free leptin levels, but do not change the concentrations of bound leptin and soluble leptin receptor. Furthermore, the dexamethasone-induced rise in leptin levels is (at least partially) independent of the effects of glucocorticoid-induced hyperinsulinaemia.     

Chronic heat stress up-regulates leptin and adiponectin secretion and expression and improves leptin, adiponectin and insulin sensitivity in mice

Heat stress (HS) induces adaptive responses that are responsible for alterations of carbohydrate and lipid metabolism. This study aimed to evaluate the effects of chronic heat treatment on the expression and secretion of leptin and adiponectin, important regulators of energy homeostasis, food intake and insulin action. C57BL/6 mice were subdivided into three groups (24 mice each). The first group was kept under control conditions (C: 22±2?°C). The second group was exposed to HS (35±1?°C). The third group was kept under control conditions and was food restricted (FR). The HS group had higher rectal temperature than the C and FR groups and lower food intake than the C group. Hspa1 (Hspa1a) gene expression in adipose tissue, muscle and liver was higher under HS than FR and C. Heat treatment resulted in decreased blood glucose and non-esterified fatty acids; increased leptin, adiponectin and insulin secretion; and greater glucose disposal. Leptin, adiponectin, leptin and adiponectin receptors, insulin receptor substrate-1 and glucose transporter mRNAs were up-regulated in HS mice. This study provides evidence that HS improves leptin and adiponectin signalling in adipose tissue, muscle and liver. Heat stress was responsible for improving insulin sensitivity and glucose uptake in peripheral tissues, probably mediated by adipokines. Changes in the adipokine levels and sensitivity to them may be considered as an adaptive response to heat.