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1.
Effects of growth factors on development of fetal islet B-cells in vitro   总被引：1，自引：0，他引：1  
To investigate the role of growth factors (epidermal growth factor [EGF], betacellulin, and activin A) in the development of islet B cells of rat fetal pancreatic explants in vitro, pancreases from rat fetuses at day 18 of gestation were cultured for 96 hr, with or without these growth factors. Culture medium was changed every 24 hr, and the level of insulin released in the culture medium was measured. After 72 hr of culture, pancreases were examined histologically. As a result, EGF promoted cell proliferation, but reduced B cell volume. Whereas, betacellulin and activin A inhibited cell division, but promoted increased B cell volume and insulin secretion, especially activin A, which stimulated insulin release in a time dependent manner. These results suggest that EGF, betacellulin, and activin A promote pancreatic cell proliferation, islet B-cell differentiation, and islet B-cell differentiation and functional maturation, respectively, and that EGF, betacellulin, and activin A, in this order, regulate islet B-cell neogenesis.  相似文献   

2.
Present electron microscopical and immunocytochemistrical studies elucidated some morphological relationship between intercalated duct (ICD) and pancreatic islet cells in the chicken in streptozotocin (STZ) and/or camostat mesilate (CM) administrations. Twenty-one chickens were set into four experimental groups: (1) control group, (2) STZ administration group, (3) CM administration group, and (4) STZ + CM administration group. Cytoplasms of ICD cells stained more strongly with eosin in STZ administration group than other groups, and electron-dense materials and intercalated processes between ICD and islet cells were also increasing in time dependence in STZ administration. Number of pancreatic islet in STZ + CM co-administration was about 3.1 times larger than other groups. Many small sized cells were detected at surrounding area of ICD and they incorporated 5-bromo-2'-deoxyuridine better than other experimental groups. Present morphological data suggested that ICD cells might support some tolerances of pancreatic endocrine cells against toxic substances and also involve in regeneration of new pancreatic islet cells in STZ + CM co-administration.  相似文献   

3.
Streptozocin (STZ) induces diabetes mellitus in sheep and pigs. To test the effect of STZ in cattle, cows were given 75-150 mg STZ per kilogram of body weight. Cows receiving 150 mg/kg required euthanasia within 24 hours after infusion because of the severe systemic effects of STZ. Seven cows receiving doses of < or = 100 mg/kg had mild to marked decrease in islet immunoreactivity for insulin and in pancreatic islet density and mild to severe tubulointerstitial nephritis. Two cows receiving 75 and 85 mg/kg STZ regained their ability to produce insulin and return blood glucose to basal levels. One cow given 100 mg/kg STZ developed insulin insufficiency consistent with type I diabetes mellitus. These findings demonstrate the susceptibility of the bovine pancreas to STZ: however, severe systemic complications were encountered. Alternative dosages and methodologies should be considered in future attempts to induce diabetes in cattle using STZ.  相似文献   

4.
In an attempt to establish a primate model of chronic cadmium (Cd) toxicosis, we ovariectomized cynomolgus monkeys and treated with CdCl2 by repeated intravenous injections for 13 to 15 months. The animals showed an increase in blood glucose from Month 10 and a decrease in blood insulin at Month 11of the Cd-treatment. Histopathological examination of the Cd-treated animals revealed islet atrophy with reduction in islet number and vacuolation of the islet cells, whereas there was no remarkable change in the acinar cells of the exocrine pancreas. In histomorphometrical examination, insulin-positive areas in the islets were significantly decreased, accompanying a relative increase of glucagon-positive areas. Large amounts of Cd accumulated in the pancreas, and metallothionein (MT), a Cd binding protein, was localized in the islets of Cd-treated animals. The present study demonstrated that the chronic intravenous injection of Cd to cynomolgus monkeys induced the accumulation of the metal in the pancreas, degeneration of islet B cells and the diabetic clinical signs. Therefore the islet B cell is one of the major targets of the chronic Cd poisoning in monkeys.  相似文献   

5.
试验旨在研究牛磺酸(Tau)对链脲佐菌素(STZ)处理后的胰岛细胞保护作用,探讨牛磺酸防治糖尿病的作用机制,为应用牛磺酸防治糖尿病提供理论依据。将体重为250~300 g大鼠麻醉后,胆总管原位灌注胶原酶V,38 ℃水浴消化胰腺组织。Histopaque 1077密度梯度离心纯化胰岛细胞,DTZ检测纯度,葡萄糖刺激检测胰岛细胞活性;再将分离纯化后的胰岛细胞分成6组:正常对照组(对照组)、牛磺酸对照组、链脲佐菌素组(STZ组) 、牛磺酸高剂量组(20 mmol/L Tau组)、牛磺酸中剂量组(10 mmol/L Tau组)、牛磺酸低剂量组(5 mmol/L Tau组);培养24 h后,测定细胞外液中超氧化物岐化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、总抗氧化能力(T-AOC)的含量。结果表明,3个水平的Tau组和Tau对照组胰岛细胞外液中的SOD、GSH-Px、T-AOC的含量较STZ组有明显的提高。同时3个水平的Tau组和Tau对照组胰岛细胞外液中的MDA较STZ组有明显的降低。因此,牛磺酸能够提高STZ诱导的胰岛细胞抗氧化能力,从而对胰岛细胞具有一定的保护和修复作用。  相似文献   

6.
将处于热应激条件下的192只35周龄新罗曼褐壳蛋鸡随机分为6组，分别饲喂不添加铬的玉米-豆粕型基础饲粮和添加作为铬源的葡萄糖耐量因子(GTF)10、20、30、40、50mg／kg的试验饲粮。52d后取血清测血糖浓度，取胰腺制作切片观察组织结构。结果：试验组亮胰岛、暗胰岛体积均增大，细胞排列紧密，结构完好，以30、40mg／kg组变化最为明显；试验组血糖浓度均低于对照组，以30mg／kg组最低；对照组胰岛体积变小，细胞结构模糊．亮胰岛的B细胞出现破损、萎缩、变性、解体及裸核等现象。结果表明。热应激条件下蛋鸡胰岛细胞出现明显病变，补铬能够缓解热应激效应，显著改善胰岛细胞的结构和功能。  相似文献   

7.
Epidermal growth factor (EGF) receptors are widely distributed in mammalian tissues, including muscle. One ligand of these receptors, heparin-binding epidermal growth factor-like growth factor (HB-EGF) is also strongly expressed in adult muscle. However, in vitro studies of EGF action in cultured muscle cells of different species have yielded conflicting results. The purpose of this study was to investigate the potential role of EGF and related factors in the growth and development of fetal ovine muscle. High affinity EGF receptors were detected on clonally purified ovine fetal myoblasts, using [(125)I] human EGF as a ligand (K(d) values of 47 and 54 pM in separate experiments). Competitive binding studies in mixed secondary cultures showed that EGF had the highest affinity for the fetal ovine receptor, followed by HB-EGF and transforming growth factor alpha (TGF-alpha). These ligands all stimulated DNA synthesis in clonally purified ovine myoblasts, with their relative potencies at 0.1 nM reflecting their receptor binding affinities. Maximal effects were seen at 1-10 nM. EGF (10 nM) did not significantly inhibit the differentiation of clonally purified fetal ovine myoblasts, although there was increased proliferation of nondifferentiating cells. Hence a variety of EGF receptor ligands have the potential to influence the proliferation ovine muscle cell precursors in utero, but it is unlikely that they promote differentiation.  相似文献   

8.
本研究通过比较常氧(20%)和低氧(5%)环境下培养牛体细胞的生长效果,进而探讨低氧对牛体细胞体外增殖的影响。选用牛的3种常用核移植供体细胞(胎儿成纤维细胞、胎儿输卵管上皮细胞、卵丘颗粒细胞)分别在常氧和低氧2种培养环境下进行连续传代培养和细胞克隆培养,并对其倍增水平和细胞克隆形成效率作比较分析。结果显示,5%的低氧环境对这3种细胞的体外增殖均有促进效果,而且各细胞的增殖水平(50.61±2.47、16.35±0.43、43.38±0.84)均显著高于常氧组(27.42±0.23、12.14±0.83、32.76±1.53,P<0.01)。以500个·皿-1(直径100mm)的细胞浓度接种培养的情况下,低氧培养的胎儿输卵管上皮细胞的克隆形成效率((53.05±4.62)%)显著高于常氧组((36.68±5.68)%)(P<0.01),而低氧组胎儿成纤维细胞和卵丘颗粒细胞获得的细胞克隆数只是略多于常氧组,差异并不显著(P>0.05)。当以1个.孔-1的细胞浓度接种于96孔板培养时,低氧组各类细胞的单细胞克隆形成效率((21.60±2.37)%、(22.29±5.42)%、(27.92±3.69)%)显著高于常氧组((12.01±1.42)%、(7.92±2.86)%、(10.49±3.07)%)(P<0.01或P<0.05)。将体外培养条件的常氧含量(20%)调减至更接近体内生理状况的低氧含量(5%)可以延长牛体细胞增殖寿命和提高单细胞克隆形成效率,对细胞生长有很好的促进作用。  相似文献   

9.
试验采用脂质体转染法与电穿孔法,以携带绿色荧光蛋白（GFP）-新霉抗性（neo-）双标记基因的pMSCV质粒转染胎牛耳成纤维细胞为供体与体外成熟的牛卵母细胞为受体构建克隆胚。研究了体外成熟培养液中添加EGF（表皮生长因子）对转基因胚的影响,不同转染方法构建供体细胞对重构胚发育的影响和在不同体外培养系统中的发育效果。结果显示,体外成熟培养液中添加EGF 30 ng/mL组的卵母细胞成熟率最高,但对后期转基因重构胚的囊胚发育率的影响,以添加EGF 20 ng/mL组的最高;以胎牛耳成纤维细胞为供体细胞,不同转染方法转染供体细胞构建重构胚,其囊胚发育率差异不显著（P>〖JP2〗0.05）;mSOFaa+颗粒细胞单层细胞共培养体系中的转基因囊胚发育率最好,该体系更适合体细胞核移植法生产转基因牛胚胎。  相似文献   

10.
为观察表皮生长因子 ( epidermalgrowth factor,EGF)对成年水牛晶状体上皮细胞增殖作用的影响。将不同浓度 EGF作用于体外培养的成年水牛晶状体上皮细胞 ,采用 MTT法测定细胞的增殖能力。结果 :EGF在浓度为 1ng/ m L和 1 0 ng/ m L作用的前 3 d促增殖作用逐渐加强 ,呈现时间依赖性 ,且在第 3 d达到最大促增殖效果。不同浓度的 EGF对晶状体上皮细胞的增殖作用不同 ,浓度在 1 0 ng/ m L作用 2 4h后即有明显的促增殖作用 ( P <0 .0 5) ,而作用72 h后最低的有效浓度为 1 ng/ m L,而且 2 50ng/ m L EGF有最大促增殖作用。结论 :EGF是诱导成年水牛晶状体上皮细胞增殖的重要因素。  相似文献   

11.
The present study was conducted to investigate the effects of bovine follicular fluid (bFF) fractions or epidermal growth factor (EGF) on cumulus cell expansion in bovine cumulus-oocyte complexes (COCs) in vitro. bFF derived from large follicles (15-20 mm) and its fractions (>100, 10-100 and <100 kDa) were added to the medium. Cumulus cell expansion was stimulated when COCs were incubated with the 10-100 and <100 kDa fractions or bFF; in contrast, the culture of COCs with the >100 kDa fraction resulted in the suppression of cumulus cell expansion. Although the >100 kDa fraction prohibited the expansion of cumulus cells in the medium with or without low concentration EGF, cumulus expansion was promoted when COCs were cultured with the >100 kDa fraction and high-concentration EGF. In conclusion, the results suggest that bFF contains promoting and inhibiting effect for expansion of cumulus cells in COCs in vitro. The inhibiting effect of bFF may act antagonistically against the effect of EGF for the event of expanding cumulus cells.  相似文献   

12.
The object of this study was to investigate the role of epidermal growth factor (EGF) and IGF-I in the regulation of preantral follicular growth, antrum formation, and granulosal cell proliferation/ apoptosis. Porcine preantral follicles were manually dissected and cultured for up to 8 d in Waymouth's (Exp. 1) or alpha-minimum Eagle's essential medium (Exp. 2 and 3) supplemented with 10 microg/mL of transferrin, 100 microg/mL of L-ascorbic acid, and 2 mU/mL of ovine FSH, in the presence (Exp. 1 and 3) or absence (Exp. 2) of 7.5% fetal calf serum. According to the experimental protocol, IGF-I (0, 1, 10, or 100 ng/mL; Exp. 1), or IGF-I (50 ng/mL), EGF (10 ng/mL) and EGF+IGF-I (Exp. 2 and 3) were added to the culture media. In Exp. 1, follicles exhibited a concentration-dependent response (P < 0.05) to IGF-I, with the highest rates of granulosal cell proliferation, follicular integrity, and recovery rate of cumulus cell-oocyte complexes and lowest incidence of apoptosis occurring at the highest IGF-I dose. In Exp. 2 serum-free medium, granulosal cell proliferation was low (1 to 5%), irrespective of whether EGF and/or IGF-I were present and cellular apoptosis was increased (P < 0.05) on d 4 and 8 in the EGF+IGF-I group compared with the addition of either factor alone. In Exp. 3, granulosal cell proliferation was high in all follicles cultured in serum-containing medium for the first 3 d, but fell sharply (P < 0.05) on d 4, except in media containing IGF-I. Collectively, EGF and IGF-I increased granulosal cell proliferation, decreased apoptosis, and promoted follicular antrum formation. These results may provide useful information for developing a preantral follicular culture system in which the oocytes are capable of fertilization and embryonic development.  相似文献   

13.
The objectives of the present studies were 1) to develop a culture system that has the positive effect of serum on granulosa cell attachment and allows subsequent expression of hormonal effects in serum-free medium and 2) to determine the effect of insulin, epidermal growth factor (EGF), estradiol (E2), and growth hormone (GH) on growth, steroidogenesis, and(or) protein synthesis of bovine granulosa cells. Cells from small (1 to 5 mm) and large (greater than 8 mm) follicles were collected from cattle and cultured for either 4 or 6 d. When cells from small follicles were cultured, insulin (5 micrograms/ml) increased (P less than .05) cell numbers (cells x 10(5)/well) severalfold compared with controls. Alone, EGF (10 ng/ml), FSH (200 ng/ml), LH (200 ng/ml), E2 (2 micrograms/ml), or GH (0 to 1,000 ng/ml) had no effect on cell numbers. However, when included with insulin, 30, 100, and 300 ng/ml of GH increased (P less than .05) granulosa cell numbers on d 4 of culture. Insulin alone increased (P less than .05) progesterone production (ng.10(5) cells-1.24 h-1) by severalfold on d 4, but EGF, FSH, LH, or GH alone had no effect and E2 inhibited progesterone production. In the presence of insulin, FSH and GH (100 ng/ml) increased (P less than .05) progesterone production on d 4 of culture, whereas EGF (10 ng/ml) elicited a decrease (P less than .05) in production. In cells from both sizes of follicles, GH (300 ng/ml) increased synthesis of cellular proteins (greater than 10 kDa). In cells from only large follicles, LH (200 ng/ml) decreased synthesis and secretion of proteins (greater than or equal to 3.5 kDa). These results support the hypothesis that GH may have direct effects on bovine ovarian function.  相似文献   

14.
Twenty-five dogs with insulin-secreting neoplasms of the pancreas were studied. The diagnosis in each case was determined by histologic evaluation of pancreatic tissue obtained at surgery. The breed distribution revealed that German Shepherd Dogs, Irish Setters, and Collies were most commonly represented. Physical examination, complete blood counts, serum biochemical analysis, and urinalysis were of little diagnostic value, aside from the finding of hypoglycemia in 21 of 25 dogs. Radiographs of the thorax and abdomen were noncontributory to the ultimate diagnosis. Prior to surgery, fasting immunoreactive insulin concentrations and blood glucose concentrations were studied. Insulin:glucose ratios, glucose:insulin ratios, and amended insulin:glucose ratios were determined from the insulin and glucose concentrations in a single blood sample in each of 28 trials. In addition, glucagon tolerance tests were performed on 12 dogs. The amended insulin:glucose ratios proved to be the most reliable for diagnosis. Pancreatic masses were evident at surgery in 23 of 25 dogs; the remaining 2 dogs had microscopic evidence of an islet cell tumor. Nineteen of the islet cell tumors were carcinomas and 6 were simply described as "islet cell tumors." The mean life expectancy after surgery was 12.3 months. Treatment for malignant islet cell tumours included frequent feeding glucocorticoids, and diazoxide.  相似文献   

15.
This study examines chemokine CXCL14-like peptide distribution in the Japanese quail (Coturnix japonica) pancreas using a specific anti-human CXCL14 antibody. CXCL14-immunoreactive cells were observed in the pancreatic islet peripheral region. The staining was abolished after pre-absorbing the antibody with recombinant human CXCL14. CXCL14-immunoreactive cells were immuno-positive for somatostatin, but not glucagon and insulin. CXCL14 secreted from somatostatin-producing cells might participate in insulin secretion modulation together with somatostatin. In addition, CXCL14 might participate in glucose homeostasis in co-operation with somatostatin and growth hormone.  相似文献   

16.
A pancreatic islet cell adenoma was suspected in a 2.5-year-old pet rat that was presented for lethargy and progressive paraparesis. Hypoglycemia was confirmed using a handheld glucometer. Mild improvement was noted after initial corticosteroid treatment. No evidence of a pituitary mass was identified on magnetic resonance imaging. Although a slight treatment response was observed following drug administration the patient's clinical condition deteriorated to the point that the owners elected to have the rat euthanized. Histopathologically, an islet cell adenoma was identified within the pancreas, along with peripheral neuropathy and muscle atrophy, which were consistent with clinical findings. Immunohistochemical staining of neoplastic cells was positive for insulin. Pancreatic islet cell adenomas are not commonly reported, and their clinical prevalence in pet rats is undetermined. The current report describes a case of pancreatic islet cell adenoma in a rat with concurrent peripheral neuropathy secondary to hypoglycemia.  相似文献   

17.
Currently, in vitro‐produced embryos derived by ovum pick up (OPU) and in vitro fertilization (IVF) technologies represent approximately one‐third of the embryos worldwide in cattle. Nevertheless, the culture of small groups of embryos from an individual egg donor is an issue that OPU‐IVF laboratories have to face. In this work, we tested whether the development and quality of the preimplantation embryos in vitro cultured in low numbers (five embryos) could be improved by the addition of epidermal growth factor, insulin, transferrin and selenium (EGF‐ITS) or by the WOW system. With this aim, immature oocytes recovered from slaughtered heifers were in vitro matured and in vitro fertilized. Presumptive zygotes were then randomly cultured in four culture conditions: one large group (LG) (50 embryos/500 μl medium) and three smaller groups [five embryos/50 μl medium without (control) or with EGF‐ITS (EGF‐ITS) and five embryos per microwell in the WOW system (WOW)]. Embryos cultured in LG showed a greater ability to develop to blastocyst stage than embryos cultured in smaller groups, while the blastocyst rate of WOW group was significantly higher than in control. The number of cells/blastocyst in LG was higher than control or WOW, whereas the apoptosis rate per blastocyst was lower. On the other hand, the addition of EGF‐ITS significantly improved both parameters compared to the control and resulted in similar embryo quality to LG. In conclusion, the WOW system improved embryo development, while the addition of EGF‐ITS improved the embryo quality when smaller groups of embryos were cultured.  相似文献   

18.
This study examined the influence of EGF on the expression of EGF receptors (EGFR) and developmental competence of embryos cultured individually versus those cultured in groups. Cat oocytes were in vitro matured and fertilized (IVM/IVF), and cleaved embryos were randomly assigned to one of seven culture conditions: one group each in which embryos were subjected to group culture supplemented with or without 5 ng/ml EGF and five groups in which embryos were subjected to single-embryo culture supplemented with EGF (0, 5, 25, 50 or 100 ng/ml). Morulae, blastocysts and hatching blastocysts were assessed at days 5 and 7; post IVF, respectively, and total blastocyst cell numbers were assessed at day 7. Relative mRNA expressions of EGFR of 2–4-cell embryos, 8–16-cell embryos, morulae and blastocysts cultured in groups or singly with or without EGF supplementation were examined. OCT3/4 and Ki67 in blastocysts derived from the group or single-embryo culture systems with or without EGF supplementation were localized. A higher rate of embryos cultured in groups developed to blastocysts than individually incubated cohorts. Although EGF increased blastocyst formation in the single-embryo culture system, EGF did not affect embryo development in group culture. Expression levels of EGFR decreased in morulae and blastocysts cultured with EGF. An increased ratio of Ki67-positive cells to the total number of cells in the blastocyst was observed in singly cultured embryos in the presence of EGF. However, EGF did not affect the expression of OCT3/4. These findings indicate that EGF enhanced developmental competence of cat embryos cultured singly by stimulating cell proliferation and modulating the EGFR expression at various developmental stages.  相似文献   

19.
具有泌乳功能的乳腺上皮细胞系可作为乳腺发育学、乳腺病理学、泌乳生物工程学研究的细胞模型,本研究测定了激素对奶牛乳腺上皮细胞系泌乳功能的影响,为阐述泌乳机制提供工作基础。应用HPLC方法对体外培养奶牛乳腺上皮细胞的酪蛋白和乳糖的分泌情况和细胞培养液中的酪蛋白、乳糖含量进行测定,以确定胰岛素、催乳素和孕酮处理后的奶牛乳腺上皮细胞的泌乳功能。试验结果表明：奶牛乳腺上皮细胞具有酪蛋白和乳糖的分泌能力,在72h内,随着细胞培养时间延长,胰岛素处理组细胞中的酪蛋白和乳糖的升高趋势不明显,孕酮处理组升高趋势较明显,催乳素处理组升高趋势很明显;胰岛素处理组、催乳素处理组和孕酮处理组细胞培养液中酪蛋白升高趋势均很明显,乳糖含量均很高,三组激素比较而言,胰岛素处理组乳糖含量最高。此外,三组激素对乳腺上皮细胞活力影响均很大,在72h之内,总体变化为：催乳素处理组和孕酮处理组细胞活力均升高,胰岛素处理组细胞活力下降。  相似文献   

20.
This paper describes a 6-year-old Simmental bull with diabetes mellitus. The animal was referred to our clinic because of severe weight loss and chronic indigestion. Clinical examination revealed markedly disturbed general condition, impaired forestomach function and polyuria. There was aciduria, glucosuria and ketonuria. The most important biochemical findings were severe hyperglycemia, markedly increased activities of hepatic enzymes and severe metabolic acidosis. Plasma concentrations of insulin, insulin-like growth factor-I, thyroxine and 3,5,3'-triiodothyronine were lower than normal, whereas those of glucagon were higher than normal. Based on these findings, a diagnosis (secondary) diabetes mellitus was made. The bull was slaughtered and histological examination revealed mixed cell pancreatitis with severe degeneration of islet cells. Immunohistochemical examination of the pancreas showed that very few insulin-, glucagon-, somatostatin- and pancreatic polypeptide, insulin-like growth factor-I and adrenomedullin-producing islet cells were present.  相似文献   

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