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Objective To study the changes and mechanism of the function of islet βcells and insulin signal transduction molecules in rats after long-term period lipid infusion.Methods Thirty SpragueDawley (SD) rats were randomly divided into free fatty acid (FFA) and normal saline (NS) groups.Catheters were implanted under pentobarbital anesthesia in the right atrium via the jugular vein and the left carotid artery.A technique for a 72-h infusion in unrestrained rats was used for triglyceride and heparin or saline infusion.The infusion period was started on day 2 after surgery.After 72-h infusion,fasting serum insulin (Ins) and FFA in the blood were determined.The glucose infusion rat (GIR) was measured by hyperinsulinemia euglycemic clamp to evaluate the peripheral insulin resistance.The intravenous glucose tolerance test (ivgtt) and islet cell perifusion was conducted to evaluate the function of islet β-cell.The rats in two groups were sacrificed,and the pancreatic islets were isolated and collected.The levels of malondialdehyde (MDA) and reduced glutathione hormone (GSH) were detected in pancreatic tissues.The expressions of insulin receptor substrate-1 (IRS-1),insulin receptor substrate-2 (IRS-2),and glucose transporter-2 (Glut2)gene in islets were detected by real-time polymerase chain reaction (PCR).Results (1)The serum FFA concentration in the FFA group was higher than in NS group [(1.56 ± 0.21) mmol/L vs (0.65 ± 0.12)mmol/L,P ＜0.01].(2)The GIR was decreased significantly in FFA group compared with NS group(P ＜0.01).(3)The glucose that stimulated insulin secretion was decreased in the FFA group.(4)The levels of MDA were significantly higher in FFA group [(1.62 ± O.18) mmol/mg prot vs (0.76 ± 0.15) mmol/mg prot,P ＜0.01].The levels of GSH were lower in FFA group [(22.54 ±2.66) mg/g prot vs (36.58 ± 3.02) mg/g prot,P ＜ 0.01].(5) The gene cxprcssion of IRS-1 in islets was significantly decreased by [(36.8±1.8)％,P ＜0.01],and the expression of IRS-2 and Glut-2 was decreased by [(29.6±1.2) ％] and [(58.7 ± 2.1) ％] in FFA group,respectively(all P ＜0.01).Conclusions Lipid infusion in long time decreased the secretion of insulin and impaired the expression of insulin signal transduction molecules in islet βcells.
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Pancreatic stellate cell (PSC) activation in islet fibrosis of insulin-resistant rats induced by high-fat diet was investigated. After 20 weeks, the glucose infusion rate and glucose-stimulated insulin secretion in high-fat group were significantly decreased while fasting plasma glucose, fasting serum insulin, free fatty acid and the basal glucagon secretion were significantly increased compared with those parameters of the control rats (P< 0.05 or P<0.01). Activated PSC and collagen fiber ( type Ⅰ and Ⅲ) were found in islets of rats fed with high-fat. The result suggests that PSC activation, proliferation and migration to islet may contribute to islet fibrosis in insulin-resistant rats.
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Objective To establish the islet ? cell rat model by the ? cell-deleting technology.Methods Tweenty-four normal male SD rats and 12 weeks old were randomly divided into 3 groups,i.e,a normal diet group(NC,n=8),the model group 1(M1,n=8),and the model group 2(M2,n=8).The rats in M1 and M2 group were injected with 100 mg/kg and 150 mg/kg of streptozocin respectively.Five days later,the rats were sacrificed.The level of insulin(Ins)and Glucagon(Glc)in the pancreatic homogenate was measured.The tail of pancreas were obtained and fixed by Bolins liquid.Immunohistochemistry was performed to evaluate the expression of Ins and Glc in islet cells.Quantitative analysis was executed by image analyzer.Results Compared with the NC group,the total pancreas island areas of beta-cell deleting rats,M1 group and M2 group,are approximately 1/7 of normal control rats.Moreover,the percentages of beta-cell areas from total pancreas island areas decreased from 74.3% down to 5.4% and 5.2%,respectively.The Ins content in pancreas tissue homogenate of beta-cell deleting rats does not reach 3% of normal ones,While the Glc content unexpectedly increases.Less alpha cells distinguished by Glc positive dying through Immunohistochemistry are observed at periphery of pancreas islands of NC group.With beta cellsdeletion,the aggregation of alpha cells from periphery to centre of pancreas islands is found in M1 and M2 groups.Furthermore,the percentages of alpha cells area from total pancreas island areas are promoted from 16.4% to 76.5%、74.4%,respectively.Conclusion The islet ? cell rat model was established by injecting large dose STZ(100 mg/kg and 150 mg/kg).
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Objective To investigate the changes of peripheral insulin resistance after lipid infusion and the effect of N-acetylcystein(NAC) intervention.Methods Thirty-seven normal male SD rats,eight weeks old,were randomly divided into three groups,FFA group,NS group and NAC group(using into NAC 300 mg/(kg?d) two weeks before infusion).Catheters were implanted into right atrium via the jugular vein and left carotid artery.A technique for a 48-h infusion in unrestrained rats was used for triglyceride and heparin or saline infusion.The infusion period started on day 2 after surgery.48-h after infusion,we determined free fat acid(FFA),nitrotyrosine,malonaldehyde(MDA),reduced glutathione hormone(GSH) level in plasma.The glucose infusion rat(GIR) was measured by hyperinsulinemia euglycemic clamp to evaluated the perpherial insulin resistance.The expressions of IRS-1,IRS-2 gene in muscle were detected by real time PCR.Results(1)The FFA,nitrotyrosine and MDA con-centrations in FFA group were higher than that in NS group,but GSH level in plasma was lower.NAC intervention could reverse these effects.(2)GIR was decreased significantly in FFA group as compared with NS group[(8.34?1.8)mg/(min?kg)] vs[(13.56?1.7)mg/(min?kg)],(P
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OBJECTIVE:To investigate the utilization of aspirin in patients with type 2 diabetes mellitus.METHODS:The utilization of aspirin in 510 inpatients with type 2 diabetes mellitus in the department of Endocrinology in our hospital from April 2004 to April 2007 was analyzed retrospectively.RESULTS:Of the total 510 cases,68.2% received aspirin,with daily dose reached 50～100mg.Aspirin was more often used in patients complicated with coronary heart disease and hypertension(P
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BACKGROUND:Bone mineral density(BMD) is still regarded as the standard of early diagnosis and treatment of osteoporosis(OP) at present.But it is found in detection that different sex,age and skeleton location have different OP detection rate,so it is necessary to analyze the difference. OBJECTIVE:To compare the difference of OP detection rate at different skeleton location between males and females with the increase of age. DESIGN:A cross-sectional study taking patients as the subjects. SETTING:Endocrine department of an artillery general hospital of Chinese PLA. PARTICIPANTS:A total of 147 patients,including 54 males and 93 females, aged from 50 to 78 years old,who were hospitalized in our outpatient clinic from September 2000 to January 2002,were selected and divided into 3 groups according to age,50 to 59 years old group (n=46,13 males and 33 females),60 to 69 years old group (n=66,26 males and 40 females) and 70 to 79 years old group (n=35,15 accordance with the OP diagnostic criteria recommended by WHO[1]. Exclusive criterion: secondary OP patients caused by chronic disease of liver,kidney, heart, and gastrointestinal tract and some endocrine disease such as diabetes,hyperthyroidism and so on. INTERVENTIONS:Every subject filled in the history questionnaire in detail.Height and body mass were measured accurately and body mass index(BMI) was calculated (kg/m2).A new type of Norland Excell plus dual-energy X-ray absorptiometry(DEXA) was used to detect BMD(g/cm2) of L2- 4 and proximate femur(neck of femur, Ward's triangle,greater trochanter).The detected values were compared with the normal data of young adults of the same sex and the T value(SD) was obtained. RESULTS:OP in lumber vertebra was predominant in female climacteric(χ 2=10.14,P< 0.01),and the detection rate of OP in lumber vertebra and neck of femur increased with age(χ 2=7.41, P< 0.05).OP in simple neck of femur increased significantly in males after 60 yeas old(χ 2=9.11,P< 0.05). Females were more liable to suffer from OP in simple lumber vertebra and in both lumber vertebra and neck of femur(χ 2=8.04,P< 0.05;χ 2=14.26,P< 0.01).Age had significant negative correlation with BMD in neck of femur,Ward's triangle and great trochanter of females(r=- 0.364,- 0.389, P< 0.01;r=- 0.504,P< 0.001),while BMI was positively correlated with L2- 4,neck of femur and great trochanter significantly(r=0.306,0.329,0.338,P< 0.05). CONCLUSION:Detection rate of OP changes with skeleton detecting location and age.It is very significant to recognize and evaluate these objective phenomena correctly for the diagnosis and treatment of OP.
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Objective:To express the GPI-anchored CD55 and recombinant transmembrane form CD55 molecules on mouse fibroblasts cell line NIH3T3, and compare their inhibitory function of complement lysis.Methods:In previous study,had constructed the transmembrane form CD55 (CD55-TM) cDNA by linking the extracellular portion of CD55 to the transmembrane and cytoplasmic domains of MCP, and then subcloned into retroviral vector pLXSN. In this experiment,had transfected recombinant CD55-TM and GPI anchored CD55 into PA317 packaging cell to generate stable virus-producing cell lines. And then, mouse fibroblasts cell line NIH3T3 was infected with the virus containing CD55, recombinant CD55-TM or pLXSN alone. The expression of these molecules on NIH3T3 cells was detected by FACS analysis. Complement killing assay was carried out using MTT colorimetric method.Results:FACS analysis showed that both CD55 and its TM version were expressed stably on NIH3T3 cells. Both kinds of CD55 molecules can efficiently protect the NIH3T3 cells from complement mediated lysis and there is no significant difference between them. Conclusion:These data showed that both GPI-anchored CD55 and its TM version can normally expressed on NIH3T3 cells and both can protect the NIH3T3 cells from human complement mediated lysis. These results confirmed the feasibility of TM CD55 based gene therapy could be used for PNH, and also provided an excellent model for the study of signal transduction mechanisms mediated by GPI-anchored protein.