小鼠胰岛的分离与纯化

目的 探讨稳定、高效的小鼠胰岛细胞的分离纯化方法.方法 采用胆总管内灌注不同浓度胶原酶(分别为0.5、1.0、1.5 g/L)消化胰腺的方法分离BALB/C小鼠胰岛,Ficoll-400不连续密度梯度离心法纯化胰岛.双硫腙(DTZ)对胰岛进行特异性染色计算胰岛产量及纯度,葡萄糖刺激释放试验体外测胰岛功能.结果 不同浓度的胶原酶在不同时间内消化胰腺后收获的胰岛数量有较大的差异,其中采用0.5 g/L胶原酶V、38 ℃水浴消化20 min组收获量最大为(230±20)个胰岛细胞团,纯度约为90%.DTZ染色后胰岛呈腥红色,形态完整.葡萄糖刺激释放实验示高糖刺激后胰岛素释放量为低糖刺激后的2.3倍.结论 胶原酶浓度、消化时间和温度是影响小鼠胰岛分离结果的重要因素,当胶原酶浓度为0.5 g/L,消化时间20 min时可获得数量较多,纯度较好的胰岛细胞.

Abstract：

Objective To investigate the stable and efficient method of isolation and purification from mice pancreas. Methods BALB/C mouse islets were isolated by different concentrations of collagenase digestion (0. 5, 1. 0, 1. 5 g/L respectively) and purificated by Ficoll density gradient centrifugation.The number, purity and vitality of the islets were analyzed. The production and purity of the islets were checked by Dithizone immunofluorescence staining. The glucose-induced insulin secretion was detected by enzyme linked immunosorbent assay (ELISA) for islet function in vitro. Results Different number of islets was obtained by mice pancreas digestion with different concentrations of collagenase and for different digestion durations.After the mouse pancreata were digested in 38 C and with 0. 5 g/L collagenase V for 20rmin, maximum number of islets was obtained, and the purity of the final preparation was ＞ 95%. After culture in vitro, insulin release of islets under high glucose stimulation was 2. 3 times of that under low glucose stimulation. Conclusion Concentration of collagenase, temperature, and digestion duration were important factors of islet isolation and purification from mice pancreas. More production and higher purity of islets were obtained under the concentration of 0. 5 g/L collagenase Ⅴ for 20 min.     

一种快速分离纯化小鼠胰岛的方法

目的 介绍一种快速分离纯化小鼠胰岛的方法及进行纯化后胰岛的活性、完整性和胰岛内结构的质量分析.方法 雄性ICR小鼠,采用2 mg/mL胶原酶V灌注和消化,并用Hanks液快速洗涤,用Histopaque（R）-1077和Histopaque（R）-1119密度梯度离心对胰岛进行纯化,用手工方法进行胰岛挑选,DTZ、FD-PI染色鉴定胰岛纯度及其活性,透射电镜观察胰岛内的结构.结果 胰岛开始消化至手工挑选前过程耗时＜ 25 min,每只小鼠得到胰岛数量为：128±36,当量为：145±42,纯度＞90％.透射电镜显示胰岛内部血管仍有损伤.结论 采用此方法可快速得到数量较多、结构较完整的小鼠胰岛,且活性高,为进一步进行胰岛的体外质量研究及体内移植奠定了基础.     

几种小鼠胰岛的分离纯化方法比较

目的探讨几种小鼠胰岛的分离纯化方法及进行纯化后胰岛的计数和完整性的分析。方法选用ICR小鼠,采用不同胶原酶消化方法和不同的胶原酶种类,并用Ficoll-PaqueTMPLUS密度梯度离心法对胰岛进行纯化,并对获得的胰岛进行DTZ染色计数和计算当量,扫描电镜考察胰岛的完整性。结果采用胶原酶V和P胰管灌注、内外消化结合,消化需时较短,胶原酶V和P在胰岛纯化前后每只小鼠收获的胰岛细胞数量和当量无差别(P>0.05);扫描电镜结果显示消化较好的胰岛表面被膜完整,消化过度的胰岛导致被膜不完整,易致外层细胞损伤。结论小鼠逆行胰管灌注胶原酶、内外消化相结合的胰岛消化方法所需时间较短,但同时要注意防止消化过度。     

胰岛分离纯化研究进展

目的综述胰岛分离纯化各步骤及常用方法,并介绍最新研究进展。方法查阅近年国内外胰岛分离纯化的相关文献,综合分析供体选择、胰腺消化分离、胰岛纯化和分离效果鉴定等流程。结果分离纯化效果取决于每一步材料和操作方法的选择及各操作步骤的衔接。结论胰岛移植是治疗1型糖尿病最有效的手段,胰岛分离纯化的优化及标准化操作可解决胰岛来源不足问题。     

家兔胰岛分离纯化方法的改进

目的介绍一种新的家兔胰岛分离纯化方法并进行纯化后胰岛的外观、活性和胰岛细胞团表面结构等质量分析。方法雄性日本大耳白,采用2 mg/m L胶原酶V逆行胰管灌注和消化,并用Hanks液洗涤,用Histopaque-1119、Histopaque-1077密度梯度离心进行胰岛纯化,DTZ、FD-PI染色鉴定胰岛纯度和活性,扫描电镜观察纯化后胰岛表面结构。结果家兔胰管开口于小肠,纯化得到家兔胰岛外形圆整,纯度90%,活性(87.4±5.9)%,纯化前胰岛当量为(1 874.8±464.5)IEQ,纯化后胰岛当量为(1 254.8±235.8)IEQ;扫描电镜结果显示胰岛细胞团表面有被膜,但部分胰岛被膜被消化。结论采用此方法可快速得到纯度高、活性好且结构完整的家兔胰岛,为进一步进行家兔胰岛体外质量及体内移植研究奠定了基础。     

成人胰岛分离纯化技术

目前,胰岛移植已经成为治疗糖尿病的有效手段之一.从供者胰腺中分离出大量高活力的胰岛是保证胰岛移植成功的必要环节.本研究自2005年3月至2008年1月共进行15例成人胰岛分离纯化,现总结如下.     

小鼠胰岛的分离纯化及体外功能检测的实验研究

目的：探讨获得高质量小鼠胰岛的分离纯化方法，评价其功能。方法：采用胆总管内胶原酶灌注膨胀消化胰腺的方法分离小鼠胰岛，不连续密度梯度离心法纯化胰岛，用双硫腙（Dithizone，DTZ）对胰岛进行特异性染色计算胰岛产量及纯度，以葡萄糖和茶碱刺激胰岛素释放检测胰岛功能。结果：胰岛的产量和活性主要与胰腺均匀膨胀和胶原酶的消化时间有关。平均每个小鼠胰腺能得到150～250个高质量胰岛，活性〉95％，纯度〉90％。葡萄糖及茶碱（carbachol，Cch）刺激后胰岛素释放量明显增加。结论：改良的胆总管内胶原酶灌注膨胀消化小鼠胰腺及不连续密度梯度Ficoll-400纯化胰岛的方法，可获得产量较高、纯度及功能较好的胰岛。     

新型胰岛分离液对小鼠胰岛分离效果的研究

目的  探讨新型胰岛分离液（IPS液）在小鼠胰岛分离中的分离效率及胰岛保护作用。方法  将消化后的小鼠胰腺按体积平均分为两组（IPS组和UW组）,分别应用IPS-Optiprep液及UW-Optiprep液进行连续梯度密度离心分离胰岛,比较两组分离液的分离纯化效率和分离后的胰岛活性。将诱导成功的糖尿病小鼠随机分为3组：实验组（n=10）,接受采用IPS-Optiprep液分离纯化的胰岛移植;对照组（n=10）,接受采用UW-Optiprep液分离纯化的胰岛移植;假性移植组（n=5）,仅给予手术但并不进行胰岛移植。分析3组小鼠术后血糖水平以及测实验组和对照组小鼠术后21 d的腹腔葡萄糖耐量试验的血糖水平。比较两种分离液的配制成本。结果  与UW组相比,IPS组的IPS-Optiprep液可提供更高的胰岛当量（IEQ）、胰岛纯度、回收率及胰岛完整度。胰岛形态观察可见,IPS组胰岛被膜完整,直径明显大于UW组。UW组纯化后的胰岛活性率高于IPS组[（88±5）%比（84±3）%,P < 0.01]。与UW-Optiprep液相比,IPS-Optiprep液可获得相当的在体胰岛功能。IPS-Optiprep液可显著降低胰岛分离纯化成本。结论  新型胰岛分离液IPS-Optiprep液在胰岛分离提纯中显示出较好的分离效率,增加了胰岛的纯度、完整度与回收率,并显著降低了纯化成本,但对胰岛细胞活性的保护作用稍逊,可能与胰岛的高完整度及IPS-Optiprep液中的内毒素有关。     

小鼠胰岛的分离及胰岛移植

目的研究小鼠胰岛分离和移植的方法。方法在Gotoh等所介绍的小鼠胰岛分离方法的基础上作了一些改进,由原来经胆总管注入胶原酶消化液改为由胆囊注入,并在消化液和Ficoll分离液中加入了胰酶抑制剂和BSA。结果使分离纯化后的胰岛产量由原来方法的41.7±13.2个提高到了266.5±32.1个(P<0.01),活性在95%以上,除了少量导管外几乎不含腺泡组织。结论改进后的方法可以在肉眼条件下注入消化液,而不需要解剖显微镜,既方便了操作又提高了成功率;避免了整个消化和分离过程中胰酶对胰岛的消化作用,提高了得率,且具有很好的重复性。     

猪胰岛细胞分离纯化研究进展

目的综述猪胰岛细胞分离纯化的常用方法及最新研究进展。方法查阅近年来国内外关于猪胰岛细胞分离纯化的相关文献,进行总结分析。结果分离纯化的效果主要取决于供体的前期筛选、高质量胰腺的获取与有效保存,以及分离纯化方法的选择与改进。结论猪胰岛分离纯化操作的优化与标准化的建立,极大促进了异种胰岛移植研究的发展,有望解决目前移植供体短缺的问题。     

Automated method for isolation of human pancreatic islets

We describe an automated method for the isolation of human pancreatic islets. The procedure meets the following requirements: 1) minimal traumatic action on the islets, 2) continuous digestion in which the islets that are progressively liberated can be saved from further enzymatic action, 3) minimal human intervention in the digestion process, and 4) high yield and purity of the isolated islets. After purification on Ficoll gradients, an average of 164,600 islets/pancreas was obtained (2279 islets/g), with an average purity of 78.5% islets. The average volume and average insulin content of the final islet preparation were 348 mm3 and 93.4 U, respectively. The islets were morphologically intact with a normal degree of beta-granulation and responded to glucose stimulation with a fivefold increase of insulin secretion over basal levels. The procedure is now being used for the initiation of the second phase of clinical trials on human islet transplants.     

Standardization fo a digestion-filtration method for isolation of pancreatic islets.

Standardization of a technic for isolating large numbers of pancreatic islets is described. This procedure employed collagenase digestion of rat pancreatic tissue in a cylindrical wire screen in order to separate isolated islets from undigested pancreas. From this basic protocol the following conditions were established: (1) the duration of the initial digestion period was found to be optimal at six minutes; (2) three subsequent digestions of one minute each effected maximum islet yield; (3) the optimal initial collagenase concentration was found to be 1,000 U. (Worthington)/ml.; and (4) proper reductions of collagenase concentrations during the three subsequent digestions were found to be 50 per cent of each preceding incubation period. This method, combined with Ficoll gradient separation, yielded a mean of 800 islets per two rat pancreases. The isolated islets appeared morphologically intact, contained 0.36 +/- 0.05 mug. protein/islet, and demonstrated a normal biphasic release of insulin in response to stimulative levels of D-glucose. The present method provides a means for obtaining a large mass of viable islet cell tissue in a short time.     

A modified automated method for isolation of viable pancreatic islets in laboratory animals

To achieve successful islet transplantation, a high viability is required. For this reason an automated method including two chambers: one for islets isolation and one for recirculation and collection was developed. Recently, we produced a modified version of this work by building a similar system of glass where marbles were not used for disaggregation, and the pancreatic tissue had to be disrupted mechanically before the digestion phase. By using the reconfigured system, we obtained 260 +/- 20 islets from each Wistar albino rat (weighing 220 to 240 g) pancreas. Islets were observed at 35 minutes after the start of perfusion (closed circuit) and the optimum time to stop the isolation determined to be 40 minutes based upon islets viability. Although the present system is configured for islet isolation from small laboratory animals (rat, mouse), we have also obtained thousands of islets at 25 minutes after treatment of a 0.5-g piece of pig pancreas. Compared to the time-consuming manual method usually used for islet isolation from small laboratory animals, the new technique is economic, easy to use, and does not reduce islets viability.     

大鼠胰岛分离、纯化技术改良

目的:探讨SD大鼠胰岛分离、纯化的较优方案,并评价依该法分离所得胰岛的生物学特性。方法:以浓度为0.75mg/ml的Ⅺ型胶原酶经胆管充分灌注大鼠胰腺;完整分离后以37℃水浴振荡消化17min,Dextron70不连续密度梯度(1.091、1.081及1.037)离心法分离、纯化胰岛;以DTZ染色鉴定胰岛并计算得率,AO-PI染色检测胰岛活性,糖刺激试验判定胰岛功能,胰岛"细胞免疫细胞化学鉴定"细胞,光镜观察体外培养胰岛的形态学变化。结果:纯化后,每只大鼠胰岛收获量为(743.60±43.07)个,胰岛纯度>90%,胰岛细胞活率>90%。在45min内每10个胰岛细胞在低糖和高糖刺激下分泌的胰岛素浓度分别为(25.35±7.00)μIU/ml和(86.48±12.75)μIU/ml。结论:依改良后的分离纯化方案分离大鼠胰岛可获得高纯度高活率的胰岛细胞,且细胞形态正常、功能良好。     

人胰岛在分离、纯化过程中的细胞凋亡及氧化损伤

目的 探讨胰岛在获取、分离及纯化等过程中出现细胞凋亡的相关因素及应对策略.方法 经供者腹主动脉灌注4℃的UW液后,切取供者胰腺,并进行胶原酶灌注、消化及梯度离心,分离、提取胰岛.分别于胶原酶灌注前、灌注后、消化后及胰岛分离后等时点,采用原位末端标记法(TUNEL法)检测胰岛细胞凋亡情况,采用比色法检测超氧化物歧化酶(SOD)与丙二醛(MDA)水平,采用HE染色和双硫腙染色观察胰岛的形态学改变.结果 在分离、纯化胰岛的各个过程中,均出现了胰岛细胞凋亡的现象,其中在胶原酶灌注后和消化后最为明显,并伴随MDA的高表达,表达水平分别为(6.18±2.38)nmol/mgprot和(9.21±2.75)nmol/mgprot,均明显高于灌注前的(4.21±1.83)nmol/mgprot(P＜0.05和P＜0.01);而此时SOD水平则显著下降,至胰岛分离后仍处于较低水平,与灌注前相比,差异均有统计学意义(P＜0.05和P＜0.01).胶原酶灌注前,胰岛结构完整;胶原酶灌注后,胰岛周围组织结构膨胀;消化后,胰岛膜性结构被破坏,但能勉强维持岛状结构;胰岛分离后结构基本完整.结论 在提取胰岛的过程中,胶原酶灌注及消化可引起胰岛细胞凋亡,其机制可能与氧化损伤有关,抗氧化措施可作为移植前保护胰岛的手段.

Abstract：

Objective To observe the changes of islet cell apoptosis and oxidation-antioxidation before the transplantation, and to explore the pathways of islet protection. Methods Fifteen human pancreases were perfused with the Hanks solution containing collagenase, then digested and isolated. During the procedure, islet cell apoptosis was detected by TUNEL, SOD and MDA in the pancreas were measured by colorimetric method, and the morphologic changes were observed by H-E staining and dithizone staining. Results In the procedure of human islet isolation, especially in the stage of digestion, the apoptosis of human islet cells occurred. In the stages of perfusion and digestion, the MDA contents reached the high levels (6. 18 ± 2. 38 and 9. 21 ± 2. 75 umol/mg protein respectively),and the structures of the islets and tissues around the islets were damaged. Conclusion In the stages of perfusion and digestion, apoptosis of islet cells can be caused by oxidation. It suggests that antioxidation is a pathway for protection of islets before transplantation.     

Cryo-isolation: a novel method for enzyme-free isolation of pancreatic islets involving in situ cryopreservation of islets and selective destruction of acinar tissue

Background

A critical component of treating type I diabetes by transplantation is the availability of sufficient high-quality islets. Currently, islets can be obtained only by reliance on an expensive, inconsistent, and toxic enzyme digestion process. As an alternative, we hypothesize that cryobiologic techniques can be used for differential freeze destruction of the pancreas to release islets that are selectively cryopreserved in situ.

Methods

Pancreases were procured from juvenile pigs with the use of approved procedures. The concept of cryo-isolation is based on differential processing of the pancreas in 5 stages: 1) infiltrating islets in situ preferentially with a cryoprotectant (CPA) cocktail via antegrade perfusion of the major arteries; 2) retrograde ductal infusion of water (or saline solution) to fully distend the gland; 3) freezing the entire pancreas to −160°C, and stored in liquid nitrogen; 4) mechanically crushing and pulverizing the frozen pancreas into small fragments; and 5) thawing, filtering and washing the frozen fragments with RPMI 1640 culture medium to remove the CPA. Finally, the filtered effluent (cryo-isolate) was stained with dithizone for identification of intact islets, and samples were taken for static glucose- stimulated insullin release assessment.

Results

As predicted the cryo-isolated contained small fragments of residual tissue comprising an amorphous mass of acinar tissue with largely intact embedded islets. The degree of cleavage of the cryoprotected islets from the freeze-destroyed exocrine cells, was variable. Islets were typically larger than their counterparts isolated from juvenile pigs with conventional enzyme-digestion techniques. Functionally, the islets from replicate cryo-isolates responded to a glucose challenge with a mean stimulation index = 3.3 ± 0.7 (n = 3).

Conclusions

An enzyme-free method of islet isolation relying on in situ cryopreservation of islets with simultaneous freeze-destruction of acinar tissue is feasible and proposed as a novel method that avoids the problems associated with conventional collagenase digestion methods.