RNA interference targeting mu-opioid receptors reverses the inhibition of fentanyl on glucose-evoked insulin release of rat islets

Background Mu opioid receptor plays an important role in many physiological functions. Fentanyl is a widely used opioid receptor agonist for analgesia. This study was conducted to test the role of mu-opioid receptor on insulin release by determining whether fentanyl affected insulin release from freshly isolated rat pancreatic islets and if small interfering RNAs （siRNA） targeting mu-opioid receptor in the islets could knock down mu-opioid receptor expression.Methods Islets were isolated from ripe SD rats＇ pancreas by common bile duct intraductal collagenase V digestion and purified by discontinuous Ficoll density gradient centrifugation. The siRNA knock-down of mu-opioid receptor mRNA and protein in islet cells was analyzed by semi-quantitative real time-PCR and Western blotting. After siRNA-transfection for 48 hours, the islets were co-cultured with fentanyl as follows： 0 ng/ml, 3 ng/ml and 30 ng/ml for 48 hours. Then glucose-evoked insulin release was performed. As a control, the insulin release was also analyzed in islets without siRNA-trasfection after being co-cultured with fentanyl for 48 hours.Results After 48 hours of transfections, specific siRNA targeting of mu-opioid receptors produced significant reduction of mu-opioid receptor mRNA and protein （P ＜0.01）. Fentanyl significantly inhibited glucose-evoked insulin release in islets in a concentration dependent manner （P ＜0.01）. But after siRNA-transfection for 48 hours, the inhibition on glucose-evoked insulin reiease was reversed （P ＜0.01）.Conclusions RNA interference specifically reduces mu-opioid receptor mRNA and protein expression, leading to reversal of the fentanyl-induced inhibition on glucose-evoked insulin release of rat islets. The activation of opioid receptor induced by fentanyl functions to inhibit insulin release. The use of RNAi presents a promising tool for future research in diabetic mechanisms and a novel therapy for diabetes.     

腺病毒载体转染人HO-1基因增强成人胰岛细胞抗凋亡和胰岛素释放功能的研究

目的了解腺病毒载体转染人HO-1基因对体外培养的成人胰岛的作用,探索基因治疗在胰岛移植中的潜在应用价值。方法将成人胰岛分离纯化后分为3组:转染人HO-1基因组(Ad-HO-1组)、转染EGFP基因组(Ad-EGFP组)及对照组,采用携带人HO-1基因及EGFP基因的腺病毒作为载体对体外培养的成人胰岛进行转染,通过形态学观察、胰岛素释放试验及肿瘤坏死因子(TNF)α及放线菌酮诱导48 h后流式细胞仪检测凋亡。结果Ad-HO-1组的胰岛在高糖刺激下胰岛素分泌量为270 m IU/L±89 m IU/L,高于对照组(182 m IU/L±59 m IU/L)和Ad-EGFP组(189 m IU/L±88 m IU/L,P<0.05);诱导后Ad-HO-1组凋亡细胞的发生率为63%±11%,对照组为91%±11%,两组比较,P<0.01。结论使用腺病毒作为载体对体外培养的成人胰岛转染HO-1基因能够增加胰岛的抗凋亡能力、促进胰岛素的分泌。     

Isolation and culture of adult Sertoli cells and their effects on the function of co-cultured allogeneic islets in vitro

Background Globally, 180 million people suffer from diabetes mellitus. Islet transplantation is believed to be an almost ideal therapy for insulin-dependent patients. How to maintain the viability and the function of isolated human islets is a challenge in clinical practice. Sertoli cells are considered ‘nurse cells’in the seminiferous tubules and have been used in cell graft protocols for neurodegenerative diseases and diabetes in many studies. Many researchers have used immature murine testes as the primarily source of Sertoli cells in islet transplantation because they are easily purified. Mature human Sertoli cells have been seldom investigated. In the present study, we developed a method for the isolation and culture of Sertoli cells derived from adult human testes, and investigated their effects on the function of allogeneic islets when they were cultured together in vitro.Methods Adult Sertoli cells were prepared successfully by two-step enzyme digestion with trypsin, collagenase and hyaluronidase. They were identified by morphological characteristics and their activity was determined by MTT colorimetry over a 28-day culture time in vitro. A glucose-stimulated insulin secretion test was performed to detect the effects of Sertoli cells on allogeneic islets’ function when they were co-cultured for 21 days in vitro.Results In cultured cells, mature human Sertoli cells accounted for more than 90% of total cells. The activity of Sertoli cells reached 95% and they remained highly cytoactive for a long time in vitro (P&gt;0.05). Compared with the islets cultured alone, the co-cultured islets with allogeneic Sertoli cells maintained higher sensitivity to glucose stimulation for the duration of the experiment (P&lt;0.01).Conclusions A method of isolation and culture of Sertoli cells from adult testes has been established. Sertoli cells could enhance allogeneic islets’ function when they were co-cultured in vitro. They could be a helper cell in islet transplantation. Chin Med J 2005; 118(22):1857-1862     

干预糖毒性对肥胖大鼠胰岛β、α细胞功能改善的作用

目的 探讨糖毒性对肥胖大鼠胰岛β、α细胞功能及分子生物学的损害作用.方法 雄性SD大鼠36只分为4组:(1)正常组:9只,普通饲料喂养.(2)高脂组:9只,高脂饲料喂养.(3)DM对照组:9只,不给予药物干预.(4)糖毒性干预组:9只,皮下注射超长效甘精胰岛素(5 U·kg-1·d-1)降低血糖,共4周.所有大鼠在实验结束时,通过免疫组化观察分析胰岛β、α细胞形态学特点,RT-PCR测定胰腺内胰岛素原mRNA表达水平,Western印迹方法检测胰腺中胰岛素蛋白质含量,胰岛素干预2周和4周后复测葡萄糖耐量试验.结果 糖毒性干预组,胰岛内β细胞比糖尿病对照组相对量增加(分别为0.38±0.08,0.11±0.05,P＜0.01),β细胞浆内胰岛素水平增加(分别为0.58±0.03,0.34±0.14,P＜0.01),胰岛素原mRNA表达增加(分别为1.52±0.14,1.26±0.14,P＜0.01);Western印迹检测胰岛素蛋白质含量明显升高;胰岛内α细胞相对量减少(分别为0.28±0.15,0.16±0.04,P＜0.01).结论 干预糖毒性4周能显著改善糖尿病大鼠胰岛β、α细胞的病理学变化,部分恢复胰岛细胞的功能.     

解偶联蛋白2基因表达与胰岛β细胞分泌功能的关系及机制

目的 观察长期高脂饮食对大鼠胰岛β细胞胰岛素分泌功能的影响,探讨解偶联蛋白2(UCP2)及相关的氧化应激在其中的作用及机制.方法 8周龄SD大鼠随机分为正常饲料组(NC组,20只)和高脂饲料组(HF组,20只).饲养20周检测以下指标:(1)血浆硝基酪氨酸,丙二醛(MDA)和还原型谷胱甘肽(GSH)水平;(2)正常血糖高胰岛素钳夹试验,评价外周组织胰岛素抵抗程度;(3)胰岛细胞表面灌注试验,评价离体胰岛β细胞动态分泌功能;(4)实时荧光定量PCR方法比较两组大鼠胰岛细胞胰岛素受体底物-1(IRS-1)、胰岛素受体底物-2(IRS-2)以及UCP2mRNA表达的变化.(5)免疫组织化学染色及图像分析检测IRS-1,IRS-2在两组大鼠胰岛中的表达.结果 (1)HF组血浆硝基酪氨酸(0.17±0.01)μmol/L和MDA(22±5)nmol/L水平高于NC组(0.14±0.02)μmol/L,(13±3)nmol/L,(P均＜0.05),GSH水平(103±9)mg/ml明显低于NC组(142±9)mg/l,(P＜0.01);(2)HF组葡萄糖输注率(GIR)较Nc组明显降低(P＜0.01);HF组葡萄糖刺激的胰岛素分泌(GSIS)功能明显下降(P＜0.01);(3)HF组胰岛细胞IRS-1及IRS-2mRNA表达分别降低42.3%、28.1%,UCP2表达增高32.5%(P均＜0.05).(4)HF组胰岛IRS-1和IRS-2的表达较对照组分别降低26.3%(P＜0.05)和11.2%(P＞0.05).(5)UCP2与胰岛细胞IRS-1 mRNA表达呈负相关(r=-0.621,P＜0.05);且与IRS-2mRNA表达也呈负相关(r=-0.416,P＜0.05).结论 长期高脂饲养能导致大鼠胰岛细胞胰岛素信号分子表达下降,β细胞胰岛素分泌功能受损,具体机制推测与UCP2相关的氧化应激增强有关.     

犬胰岛的分离与纯化

目的探讨影响胰岛分离与纯化结果的相关因素,寻找获得足够数量、高纯度、具有活性的胰岛细胞的方法,为临床胰岛移植应用提供实验基础。方法寻找自动分离技术连续分离22只犬的胰岛,连续性密度梯度离心法纯化胰岛,观察分离纯化出来的胰岛细胞大体形态、超微结构,用葡萄糖刺激释放实验检验其活性。结果纯化前胰岛计数平均为（155040±310）IEQ／胰腺,纯化后的胰岛平均计数为（74200±185）IEQ／胰腺,纯度约为（89．4±2．6）％,回收率约为（47．8±1．3）％,活率达到（93．0±1．7）％。胰岛分离纯化的结果无论在数量上还是在质量上都随着分离技术的不断更新,操作技术的娴熟而有很大提高。葡萄糖刺激释放实验显示低糖组与高糖组比较P〈0．001,提示分离纯化后获得的胰岛功能状态良好。结论从犬中分离和纯化出足够数量的胰岛细胞,可用于临床研究。     

Protection of rat islet viability following heme oxygenase-1 gene transfection via adenoviral vector in vitro

Objective： To investigate the effect of Heme oxygenase-1 （HO-1） gene transfection on the viability of cultured rat islets, and to explore the potential value of HO-1 gene in islet transplantation. Methods：Recombinant adenovirus vector containing human HO-1 gene（Ad-HO-1 ） or enhanced green fluorescent protein gene（Ad-EGFP） was generated by using AdEasy system respectively. The rat islets were transfected with Ad-HO-1, Ad-EGFP or blank vector and then cultured for 7 days. Transfection was confirmed by expression of EGFP and human HO-1 protein detected by fluorescence photographs and western blot, respectively. The insulin release upon different concentration of glucose stimulation was detected using insulin radioimmunoassay kit, and stimulation index（SI） was calculated. Glucose-stimulated insulin release was used ＇to assess islet viability. Results：Adenovirus vector successfully transferred HO-1 gene to rat islet cells in vitro, and the insulin release upon high level of glucose stimulation and stimulation index （SI） of Ad-HO-1-infected islets were significantly higher than those of Ad-EGFP-infected islets and control islets （P 〈 0.05）. Conclusion： Adenovirus-mediated HO-1 gene transfection is a feasible strategy to confer cytoprotection and therefore protect the viability of cultured rat islets.     

iPLA2在人胰岛β细胞的表达和对胰岛素分泌功能的影响

目的 探讨Ca2+-非依赖性磷酸脂酶A2(iPLA2)在人胰岛的表达及在胰岛素分泌功能中的作用.方法 正常人胰腺组织切片免疫组织化学染色及人胰岛Western印迹方法检测,观察iPLA2在人胰岛中的表达情况;随机分组对照研究iPLA2选择性抑制剂溴烯醇内酯(BEL)对离体人胰岛的葡萄糖刺激引起胰岛素分泌反应的影响.结果 在人胰岛iPLA2高表达,与抗胰岛素染色分布一致,而外分泌腺很少表达;与对照组相比,BEL处理组胰岛素分泌反应明显减弱(P＜0.01),BEL通过抑制iPLA2活性抑制了葡萄糖刺激引起的离体人胰岛胰岛素分泌.结论 iPLA2在人胰岛β细胞高表达并在葡萄糖刺激胰岛β细胞胰岛素分泌过程起到重要的作用.     

表皮生长因子对体外长期孵育保存的人胎胰岛的支持作用

目的：研究表皮生长因子(EGF)对促进人胎胰岛增殖与分泌功能．方法：12个人胎胰岛分别在含有EGF(实验组)和不含有EGF(对照组)的培养基中孵育，观察胰岛B细胞的分布，测定培养基中和细胞内胰岛素浓度和胰岛素释放量．结果：培养结束后实验组胰岛B细胞明显高于对照组；培养基和胰岛B细胞中胰岛素释放量实验组高于对照组．结论：培养液中加入EGF能延长胰岛细胞存活期、促进胰岛细胞增殖和分泌功能．     

Protection of human islets from induction of apoptosis and improved islet function with HO-1 gene transduction

Background Islet transplantation represents an ideal therapeutic approach for treatment of type 1 diabetes but islet function and regeneration may be influenced by necrosis or apoptosis induced by oxidative stress and other insults. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in the catabolism of heme into biliverdin, releasing free iron and carbon monoxide. It has also been reported to be an antioxidant enzyme which can improve the function of grafted islets by cytoprotection via free radical scavenging and apoptosis prevention. In the present study, we investigated whether transduction of HO-1 genes into human islets with an adenovirus vector has cytoprotective action on islets cultured in vitro and discuss this method of gene therapy for clinical islet transplantation.Methods Cadaveric pancreatic islets were isolated and purified in vitro. Transduction efficiency of islets was determined by infecting islets with adenovirus vector containing the enhanced green fluorescent protein gene (Ad-EGFP) at multiplicities of infection (MOI) of 2, 5, 10, or 20. Newly isolated islets were divided into three groups: EGFP group, islets transduced with Ad-EGFP using MOI＝20; HO-1 group, transduced with adenovirus vectors containing the human HO-1 gene using MOI＝20; and control group, mock transduced islets. Insulin release after glucose stimulation of the cell lines was determined by a radioimmunoassay kit and the stimulation index was calculated. Flow cytometry was used to detect apoptotic cells in the HO-1 group and in the control group after induction by recombinant human tumor necrosis factor-α (rTNFα) and cycloheximide (CHX) for 48 hours.Results Adenovirus vectors have a high efficiency of gene transduction into adult islet cells. Transduction of islets with the Ad-EGFP was most successful at MOI 20, at which MOI fluorescence was very intense on day 7 after transduction and EGFP was expressed in cultured islet cells for more than four weeks in vitro. The insulin release in the control group was (182.36±58.96) mIU/L after stimulation by high glucose media (16.7 mmol/L), while insulin release from the HO-1 group and the EGFP group were (270.09±89.37) mIU/L and (175.95±75.05) mIU/L respectively. Compared to the control group and the EGFP group, insulin release in the HO-1 group increased significantly (P＜0.05). After treatment with rTNFα and CHX the apoptotic ratio of islet cells was (63.09±10.86)% in the HO-1 group, significantly lower than (90.86±11.25)% in the control group (P&lt;0.05).Conclusions Transduction of human islets with Ad-HO-1 can protect against TNF-α and CHX mediated cytotoxicity. The HO-1 gene also appears to facilitate insulin release from human islets. Transduction of donor islets with the adenovirus vector containing an HO-1 gene might have potential value in clinical islet transplantation.     

小鼠胰岛α细胞的缺失对移植胰岛功能的影响

目的　探讨胰岛α细胞的丢失对胰岛素分泌功能的影响。方法　在人胰岛分离过程中 ,经胶原酶的过度消化造成胰岛周边α细胞缺失 ,用免疫组化及胰岛素 /胰高糖素含量分析予以证实。在体外 ,检测葡萄糖刺激引起的实验性糖尿病小鼠胰岛素的分泌 ;在体内 ,评价胰岛移植后对糖尿病小鼠血糖的调节 ,并研究胰高糖素对α细胞缺失胰岛功能的影响。结果　胶原酶的过度消化引起胰岛周边的α细胞丢失 ,使分离胰岛内胰岛素 /胰高糖素比值明显升高。与正常胰岛相比 ,α细胞缺失胰岛对葡萄糖刺激产生的胰岛素明显降低 ,胰岛素释放在正常胰岛和α细胞缺失胰岛分别为2 2 2 7uU/ml± 32 1uU/ml和 12 4 6uU/ml± 12 6uU/ml(P <0 0 1)。在体内 ,移植α细胞缺失的胰岛到糖尿病的C5 7/BL小鼠后不能有效地纠正动物的高血糖 ,胰岛移植后的平均血糖浓度在正常胰岛组和α细胞缺失胰岛组分别为 :8 9mmol/L± 1 98mmol/L和 2 1 3mmol/L± 2 2mmol/L(P <0 0 1) ,而给予外源性的胰高糖素可以在体外及体内明显改善α细胞缺失胰岛的胰岛素分泌功能。结论　胰岛α细胞的缺失明显降低胰岛的胰岛素分泌功能 ,用外源性的胰高糖素可以改善α细胞缺失胰岛的胰岛素分泌功能。     

EFFECTS OF ACUTE HYPOGLYCEMIA ON THE OREXIN SYSTEM IN RAT

OREXIN isa kind of new neuropeptideisolated from rathypothalamus, which involvedin many physiologicalregulationprogressesvia orexin1receptor(OX R )and orexin2 receptor(OX R ).The physio- 1 2logicalfunctionoforexinisstillnotcompletelyknown ,butitisidentifiedthatorexinis involvedinmany physiologicalprogressesuchasfeeding,sleep,and stress.1However ,itisstillunknown abouttheregulationoforexinsystemby hypo-thalamus,theregulationtopancreasby orexinsystem,and the regulationbetween orexin,bloodglu…     

Fas配体表达对同种胰岛移植的影响

目的探究睾丸细胞FasL表达能否对共移植的胰岛移植物提供免疫豁免作用以及胰岛细胞FasL基因转染对同种胰岛移植的影响。方法　将同种大鼠胰岛及睾丸细胞同时移植于糖尿病受体，重组腺病毒AdV-FasL感染胰岛细胞后移植，观察移植物存活情况、胰岛功能，并检测移植物内浸润淋巴细胞以及基因转染胰岛细胞凋亡情况。结果　单纯移植胰岛组平均存活期为(6.3±0.6)d。与胰岛细胞同时移植的睾丸细胞数增加至1×107时，存活期大于50d（P<0.05）。表达FasL的睾丸细胞在移植物内诱导浸润淋巴细胞凋亡。FasL基因转染组出现排斥加速，存活期缩短至(3.4±0.2)d。FasL转染的胰岛细胞在移植后24h见FasL表达，48h表达增强，移植后FasL转染胰岛细胞凋亡。结论　表达FasL的睾丸细胞与胰岛同时移植可诱导活化的淋巴细胞凋亡，使胰岛移植物获得免疫豁免、存活期延长，但通过FasL基因转染使胰岛细胞直接表达FasL引起胰岛细胞凋亡和粒细胞浸润，导致排斥加速。     

促红细胞生成素对新生猪胰岛细胞 增殖分化和凋亡的影响

［摘要］目的：研究促红细胞生成素在体外对新生猪胰岛细胞增殖分化和凋亡的影响。方法：采用胶原酶消化和组织培养方法分离纯化新生猪胰岛细胞,检测其纯度和活性,再分为实验组和对照组。实验组培养基中添加促红细胞生成素（10.0 μmol/L）,对照组不添加促红细胞生成素,培养5 d后行低糖和高糖刺激胰岛素释放试验;并行细胞计数及MTT比色法测细胞增殖活性;流式细胞仪和EB/AO染色荧光检测细胞凋亡百分率,流式细胞仪分析细胞周期,RT-PCR法检测胰岛细胞胰岛素促进因子-1(PDX-1),葡萄糖转运载体2（GlUT-2）,bcl-2,bax,caspase-3 mRNA的表达。结果：促红细胞生成素干预后新生猪胰岛细胞不改变形态和功能,对葡萄糖刺激胰岛素分泌的反应正常;细胞计数示实验组新生猪胰岛细胞数目均比对照组增多（P＜0.05）;随着培养时间延长,实验组和对照组吸光度值均呈上升趋势,且实验组的吸光度值均高于对照组（P＜0.05）,实验组PDX-1 mRNA表达稍有上调（P＜0.05）,而GlUT-2 mRNA表达无明显差别（P=0.34）。流式细胞仪和EB/AO染色荧光检测实验组的凋亡百分率均较对照组降低（P＜0.01）。RT-PCR示实验组bcl-2 mRNA较对照组上调,而bax和 caspase-3 mRNA明显下调（P＜0.01）。结论：促红细胞生成素在体外能促进新生猪胰岛细胞的增殖分化,对形态和功能无影响。促红细胞生成素对新生猪胰岛细胞有抗凋亡保护作用,可能是通过上调bcl-2 mRNA的表达,下调bax, caspase-3 mRNA的表达来实现的。     

The effect of FasL expression on pancreatic islet allografts

目的　探究睾丸细胞FasL表达能否对共移植的胰岛移植物提供免疫豁免作用以及胰岛细胞FasL基因转染对同种胰岛移植的影响。方法　将同种大鼠胰岛及睾丸细胞同时移植于糖尿病受体 ,重组腺病毒AdV FasL感染胰岛细胞后移植 ,观察移植物存活情况、胰岛功能 ,并检测移植物内浸润淋巴细胞以及基因转染胰岛细胞凋亡情况。结果　单纯移植胰岛组平均存活期为 (6 3± 0 6 )d。与胰岛细胞同时移植的睾丸细胞数增加至 1× 10 7时 ,存活期大于 6 0d(P <0 0 5 )。表达FasL的睾丸细胞在移植物内诱导浸润淋巴细胞凋亡。FasL基因转染组出现排斥加速 ,存活期缩短至 (3 4± 0 2 )d。FasL转染的胰岛细胞在移植后 2 4h见FasL表达 ,4 8h表达增强 ,移植后FasL转染胰岛细胞凋亡。结论　表达FasL的睾丸细胞与胰岛同时移植可诱导活化的淋巴细胞凋亡 ,使胰岛移植物获得免疫豁免、存活期延长 ,但通过FasL基因转染使胰岛细胞直接表达FasL引起胰岛细胞凋亡和粒细胞浸润 ,导致排斥加速。     

免疫抑制剂依维莫司对大鼠胰岛细胞的毒性作用

目的 观察依维莫司等免疫抑制剂对大鼠胰岛瘤细胞(INS-1)和SD大鼠正常胰岛细胞代谢活性和功能的影响,旨在探讨依维莫司在胰岛移植免疫抑制治疗中的安全性和可行性.方法 不同浓度梯度免疫抑制剂依维莫司、西罗莫司、环胞霉素A和霉酚酸酯处理INS-1和正常胰岛细胞,用MTT法检测细胞的代谢活性;用葡萄糖刺激胰岛素分泌实验检测胰岛细胞的胰岛素分泌功能.结果 临床血药浓度以上的依维莫司和西罗莫司高浓度组胰岛细胞增殖抑制率低于环胞霉素A和霉酚酸酯(P＜0.05);依维莫司在临床血药浓度范围和其它免疫抑制剂一样可以抑制胰岛细胞的胰岛素分泌功能,各组间的刺激指数差异无统计学意义.结论 依维莫司和西罗莫司对INS-1细胞及SD大鼠胰岛的毒性作用较小,环胞霉素A和霉酚酸酯对INS-1和SD大鼠胰岛具有较为明显的毒性作用,依维莫司有望作为新型免疫抑制剂应用于临床胰岛移植.     

吡格列酮对2型糖尿病大鼠胰岛素抵抗和胰岛功能的影响

目的:建立2型糖尿病（T2DM）的大鼠模型,观察吡格列酮（PIO）对胰岛素抵抗和胰岛功能的影响。方法:SD雄性大鼠40只,随机分为对照组（10只）和高脂组（30只）。高脂组建立2型糖尿病大鼠模型,得到T2DM大鼠24只。将成模的24只T2DM大鼠随机分为糖尿病组（DM组）和PIO组,每组12只。监测DM组、PIO组和对照组大鼠体质量、空腹血糖、空腹胰岛素、糖化血红蛋白、超敏C反应蛋白以及血脂,计算胰岛素抵抗指数、胰岛β细胞功能指数（HOMA-β）以及胰岛素敏感指数。结果:DM组、PIO组大鼠的体质量、总胆固醇、三酰甘油、低密度脂蛋白胆固醇、空腹血糖、空腹胰岛素、糖化血红蛋白、超敏C反应蛋白、胰岛素抵抗指数均高于对照组（P<0.05~P<0.01）,高密度脂蛋白胆固醇、胰岛素敏感指数和HOMA-β则均低于对照组（P<0.05~P<0.01）;PIO组的HOMA-β高于DM组（P<0.05）。结论:PIO发挥治疗T2DM大鼠糖尿病的作用可能与减轻T2DM大鼠的胰岛素抵抗和改善胰岛功能有关。     

天麻素对STZ损伤INS-1细胞的保护和修复作用

目的研究天麻素（GAS）对大鼠胰岛素瘤细胞（INS-1）的影响,及其对链脲佐菌素（STZ）损伤INS-1细胞的保护和修复作用。方法实验分正常对照组（NC）,天麻素组（GAS）,STZ损伤组（STZ）,天麻素保护组（GAS＋STZ）和天麻素修复组（STZ＋GAS）。INS-1细胞传代培养后,用四氮唑蓝（MTT）法测定细胞活力,放免法测定胰岛素分泌量,比色法测定丙二醛（MDA）含量和总抗氧化能力（T—AOC）。结果GAS可促进INS-1细胞分泌胰岛素（P〈0．05,P〈0．01）,低浓度GAS可增强INS-1细胞活力（P〈0．01）;GAS可提高STZ损伤的INS-1细胞活力（P〈0．01）,高浓度的GAS对STZ损伤的INS-1细胞具有修复作用,可促进胰岛素的分泌（P〈0．01）;GAS可降低STZ损伤的INS-1细胞的MDA含量（P〈0．01）,提高STZ损伤的INS-1细胞的T．AOC（P〈0．01）。结论GAS能够增强INS-1细胞活力,促进胰岛素分泌,减轻STZ对INS-1细胞的损伤,提高STZ损伤的INS-1细胞的抗氧化能力。     

Activated pancreatic stellate cells can impair pancreatic islet function in mice

Background

Pancreatic or islet fibrosis is often associated with activated pancreatic stellate cells (PSCs). PSCs are considered not only to promote fibrosis, but also to be associated with glucose intolerance in some diseases. We therefore evaluated morphological and functional relationships between islets and PSCs in the normal mouse pancreas and transplanted islets.

Methods

Immunohistochemistry was used to map the presence of PSCs in the normal mouse pancreas and islets implanted under the renal capsule. We isolated and cultured mouse PSCs and characterized them morphologically by immunofluorescence staining. Furthermore, we measured their cytokine production and determined their effects on insulin release from simultaneously cultured islets.

Results

PSCs were scattered throughout the pancreas, with occasional cells within the islets, particularly in the islet capsule. In islet transplants they were found mainly in the graft periphery. Cultured PSCs became functionally activated and produced several cytokines. Throughout the culture period they linearly increased their production of interleukin-6 and mammalian keratinocyte-derived chemokine. PSC cytokine production was not affected by acute hyperglycemia. Syngeneic islets co-cultured with PSCs for 24–48 h increased their insulin release and lowered their insulin content. However, short-term insulin release in batch-type incubations was unaffected after 48 h of co-culture. Increased islet cell caspase-3 activation and a decreased islet cell replication were consistently observed after co-culture for 2 or 7 days.

Conclusion

Activated PSCs may contribute to impaired islet endocrine function seen in exocrine pancreatitis and in islet fibrosis associated with some cases of type 2 diabetes.     

腺病毒介导的白细胞介素10基因转移对胰岛β细胞凋亡及胰岛素释放的影响

目的 了解鼠白细胞介素10(mIL-10)基因转移对RINm5F胰岛β细胞凋亡及胰岛素释放功能的影响,以探讨其对1型糖尿病的潜在治疗价值.方法 携带有IL-10基因的重组腺病毒载体Ad-mIL-10感染RINm5F细胞(Ad-mIL-10组),并设置重组腺病毒载体(Ad-eGFP)组及未感染组为对照,通过RT-PCR、Western印迹及酶联免疫吸附试验(ELISA)分别检测IL-10基因和蛋白表达,四甲基偶氮唑盐(MTT)法分析细胞活力,放射免疫法行胰岛素释放实验.检测加入白细胞介素1-β(IL-1β)诱导细胞破坏后,Ad-mIL-10对培养上清中一氧化氮(NO)、一氧化氮合酶(NOS)水平的影响,Hoechst33258核染色分析细胞凋亡,流式细胞仪检测细胞表面Fas表达.结果 RINm5F细胞中检测到mIL-10基因及蛋白的有效表达,培养液中町测得IL-10蛋白.IL-10重组腺病毒感染胰岛β细胞后仍具有在高糖浓度下刺激胰岛素分泌的功能.将IL-1β作用于细胞后,Ad-mIL-10组NO、NOS水平低于未感染组及Ad-eGFP组[NO水平(nmol/106 cells):52.9±3.2比227.3±26.4、235.1±28.6,均P＜0.05;NOS水平(U/106 cells):9.3±1.2比29.8 ±2.5、30.5±2.8,均P＜0.05].Fas表达阳性细胞数明显低于未感染组及Ad-eGFP组(24.6%±1.0%比33.3%±5.1%、32.6%±1.1%,均P＜0.05);细胞凋亡率也低于其他两组(9.4%±1.1%比19.2%±2.2%、20.6%±2.3%,均P＜0.05).结论 携有mIL-10基因的重组腺病毒可在RINm5F细胞有效表达,通过抑制IL-1β诱导的Fas表达而起到抗凋亡作用,胰岛细胞生理功能不受影响.