Highly efficient differentiation of human ES cells and iPS cells into mature pancreatic insulin-producing cells

Human pluripotent stem cells represent a potentially unlimited source of functional pancreatic endocrine lineage cells. Here we report a highly efficient approach to induce human embryonic stem （ES） cells and induced pluripo- tent stem （iPS） cells to differentiate into mature insulin-producing cells in a chemical-defined culture system. The differentiated human ES cells obtained by this approach comprised nearly 25% insulin-positive cells as assayed by flow cytometry analysis, which released insulin/C-peptide in response to glucose stimuli in a manner comparable to that of adult human islets. Most of these insulin-producing cells co-expressed mature β cell-specific markers such as NKX6-1 and PDX1, indicating a similar gene expression pattern to adult islet β cells in vivo. In this study, we also demonstrated that EGF facilitates the expansion of PDXl-positive pancreatic progenitors. Moreover, our protocol also succeeded in efficiently inducing human iPS cells to differentiate into insuIin-producing ceils. Therefore, this work not only provides a new model to study the mechanism of human pancreatic specialization and maturation in vitro, but also enhances the possibility of utilizing patient-specific iPS cells for the treatment of diabetes.

In vitro derivation of functional insulin-producing cells from human embryonic stem cells

The capacity for self-renewal and differentiation of human embryonic stem （ES） cells makes them a potential source for generation of pancreatic beta cells for treating type I diabetes mellitus. Here, we report a newly developed and effective method, carried out in a serum-free system, which induced human ES cells to differentiate into insulin-producing cells. Activin A was used in the initial stage to induce definitive endoderm differentiation from human ES cells, as detected by the expression of the definitive endoderm markers Sox17 and Brachyury. Further, all-trans retinoic acid （RA） was used to promote pancreatic differentiation, as indicated by the expression of the early pancreatic transcription factors pdxl and hlxb9. After maturation in DMEM/F12 serum-free medium with bFGF and nicotinamide, the differentiated cells expressed islet specific markers such as C-peptide, insulin, glucagon and glut2. The percentage of C-peptide-positive cells exceeded 15%. The secretion of insulin and C-peptide by these cells corresponded to the variations in glucose levels. When transplanted into renal capsules of Streptozotocin （STZ）-treated nude mice, these differentiated human ES cells survived and maintained the expression of beta cell marker genes, including C-peptide, pdxl, glucokinase, nkx6.1, lAPP, pax6 and Tcfl. Thirty percent of the transplanted nude mice exhibited apparent restoration of stable euglycemia; and the corrected phenotype was sustained for more than six weeks. Our new method provides a promising in vitro differentiation model for studying the mechanisms of human pancreas development and illustrates the potential of using human ES cells for the treatment of type I diabetes mellitus.

A secretory function of human insulin-producing cells in vivo

BACKGROUND: Mesenchymal stem cells derived from human umbilical cord blood (UCB-MSCs) have good research and application prospects in the treatment of diabetes. We once induced UCB-MSCs to differentiate into insulin-producing cells (IPCs) in vitro, but we did not know the functions of these cells in vivo. The aim of this study was to assess the functional effects of IPCs on insulin secretion and their role in the treatment of diabetes in vivo. METHODS: UCB-MSCs were induced to IPCs by an inducing protocol with extracellular matrix gel. BALB/C nude mice were made hyperglycemic by intraperitoneal injection of streptozotocin. The diabetic mice were transplanted with 1x10(7) IPCs under the renal capsule or with phosphate-buffered saline as a control. After transplantation, the grafts were analyzed by immunocytochemistry for the expression of human insulin; the serum human insulin levels were measured; and blood glucose and body weight status were monitored. RESULTS: Immunofluorescence showed that numerous IPCs under the kidney capsule were insulin-positive. On day 14 after transplantation, the serum human insulin level of the treatment group (n=9) averaged 0.44 +/- 0.12 mU/L, which was higher than that of the control group (n=9) that did not express insulin (t=10.842, P<0.05). The diabetic mice remained hyperglycemic and kept losing body weight after IPC transplantation, and there was no significant difference in the control group. CONCLUSION: IPCs differentiated from UCB-MSCs generate human insulin in diabetic mice, but more research is needed to make further use of them to regulate hyperglycemia and body weight in vivo. (Hepatobiliary Pancreat Dis Int 2009; 8: 255-260)

In vitro-derived insulin-producing cells modulate Th1 immune responses and induce IL-10 in streptozotocin-induced mouse model of pancreatic insulitis

Background: Insulitis is defined by the presence of immune cells infiltrating in the pancreatic islets that might progress into the complete β-cell loss. The immunomodulatory properties of bone marrow-derived mesenchymal stem cells(BM-MSCs) have attracted much attention. This study aimed to evaluate the possible immunomodulatory effects of rat BM-MSCs and MSCs-derived insulin-producing cells(IPCs) in a mouse model of pancreatic insulitis. Methods: Insulitis was induced in BALB/c mice using five consecuti ve doses of streptozotocin. MSCs or IPCs were directly injected into the pancreas of mice and their effects on the expression of Th subsetsrelated genes were evaluated. Results: Both BM-MSCs and IPCs significantly reduced the expression of pancreatic Th1-related IFN-γ( P < 0.001 and P < 0.05, respectively) and T-bet genes(both P < 0.001). Moreover, the expression of IL-10 gene was significantly increased in IPC-treated compared to BM-MSC-or PBS-treated mice( P < 0.001 both comparisons). Conclusions: BM-MSCs and IPCs could successfully suppress pathologic Th1 immune responses in the mouse model of insulitis. However, the marked increase in IL-10 gene expression by IPCs compared to BM-MSCs suggests that their simultaneous use at the initial phase of autoimmune diabetes might be a better option to reduce inflammation but these results need to be verified by further experiments.

Induction of pancreatic duct cells of neonatal rats into insulin-producing cells with fetal bovine serum: A natural protocol and its use for patch clamp experiments

AIM： To induce the pancreatic duct cells into endocrine cells with a new natural protocol for electrophysiological study. METHODS： The pancreatic duct cells of neonatal rats were isolated, cultured and induced into endocrine ceils with 15% fetal bovine serum for a period of 20 d. During this period, insulin secretion, MTT value, and morphological change of neonatal and adult pancreatic islet cells were comparatively investigated. Pancreatic β-cells were identified by morphological and electrophysiological characteristics, while ATP sensitive potassium channels （KATP）, voltage-dependent potassium channels （Kv）, and voltage-dependent calcium channels （KcA） in β-cells were identified by patch clamp technique. RESULTS： After incubation with fetal bovine serum, the neonatal duct cells budded out, changed from duct-like cells into islet clusters. In the first 4 d, MTT value and insulin secretion increased slowly （MTT value from 0.024 ±0.003 to 3.028±0.003, insulin secretion from 2.6±0.6 to 3.1±0.8 mIU/L）. Then MTT value and insulin secretion increased quickly from d 5 to d 10 （MTT value from 0.028 ±0.003 to 0.052±0.008, insulin secretion from 3.1±0.8 to 18.3±2.6 mIU/L）, then reached high plateau （MTT value 〉0.052±0.008, insulin secretion 〉18.3±2.6 mIU/L）. In contrast, for the isolated adult pancreatic islet cells, both insulin release and MTT value were stable in the first 4 d （MTT value from 0.029±0.01 to 0.031±0.011, insulin secretion from 13.9±3.1 to 14.3±3.3 mIU/L）, but afterwards they reduced gradually （MTT value 〈0.031 ±0.011, insulin secretion 〈8.2±1.5 mIU/L）, and the pancreatic islet cells became dispersed, broken or atrophied correspondingly. The differentiated neonatal cells were identified as pancreatic islet cells by dithizone staining method, and pancreatic β-cells were further identified by both morphological features and electrophysiological characteristics, i.e. the existence of recording currents from KATP, Kv, and KCA. CONCLUSION： Islet cells differentiated from neonatal pancreatic duct cells with the new natural protocol are more advantageous in performing patch clamp study over the isolated adult pancreatic islet cells.

Conophylline Promotes the Proliferation of Immortalized Mesenchymal Stem Cells Derived from Fetal Porcine Pancreas (iPMSCs)

Conophylline, is a bis （indole） alkaloid consisting of two pentacyclic aspidosperma skeletons, isolated from Tabernaemontana divaricata, which has been found to induce β-cell differentiation in rat pancreatic acinar carcinoma cells and in cultured rat pancreatic tissue. However, the precise role of conophylline in the growth and survival of immortalized pancreatic mesenchymal stem cells （iPMSCs） derived from fetal porcine pancreas were not understood at present. To determine whether this molecule is involved in controlling the proliferation of iPMSCs, we examined the effects of conophylline on iPMSCs. We found that conophylline can robustly stimulate iPMSCs proliferation, even promote their potential differentiation into islet-like clusters analyzed by cell counting, morphology, RT-PCR and real-time PCR, Western blotting, glucose-stimulated insulin release and insulin content analysis. The effects of conophylline were inhibited by LY294002, which is the inhibitor of the PI3K pathway. These results suggest that conophylline plays a key role in the regulation of cell mass proliferation, maintenance of the undifferentiated state of iPMSCs and also promotes iPMSCs differentiated into insulin-producing cells.

Comparison between the therapeutic effects of differentiated and undifferentiated Wharton’s jelly mesenchymal stem cells in rats with streptozotocin-induced diabetes

BACKGROUND Despite the availability of current therapies,including oral antidiabetic drugs and insulin,for controlling the symptoms caused by high blood glucose,it is difficult to cure diabetes mellitus,especially type 1 diabetes mellitus.AIM Cell therapies using mesenchymal stem cells(MSCs)may be a promising option.However,the therapeutic mechanisms by which MSCs exert their effects,such as whether they can differentiate into insulin-producing cells (IPCs) beforetransplantation, are uncertain.METHODSIn this study, we used three types of differentiation media over 10 d to generateIPCs from human Wharton’s jelly MSCs (hWJ-MSCs). We further transplantedthe undifferentiated hWJ-MSCs and differentiated IPCs derived from them intothe portal vein of rats with streptozotocin-induced diabetes, and recorded thephysiological and pathological changes.RESULTSUsing fluorescent staining and C-peptide enzyme-linked immunoassay, we wereable to successfully induce the differentiation of hWJ-MSCs into IPCs.Transplantation of both IPCs derived from hWJ-MSCs and undifferentiated hWJMSCshad the therapeutic effect of ameliorating blood glucose levels andimproving intraperitoneal glucose tolerance tests. The transplanted IPCs homedto the pancreas and functionally survived for at least 8 wk after transplantation,whereas the undifferentiated hWJ-MSCs were able to improve the insulitis andameliorate the serum inflammatory cytokine in streptozotocin-induced diabeticrats.CONCLUSIONDifferentiated IPCs can significantly improve blood glucose levels in diabetic ratsdue to the continuous secretion of insulin by transplanted cells that survive in theislets of diabetic rats. Transplantation of undifferentiated hWJ-MSCs cansignificantly improve insulitis and re-balance the inflammatory condition indiabetic rats with only a slight improvement in blood glucose levels.

Role of miR-128/216a Regulating Isl1 Expression during Differentiation of Human Umbilical Cord Mesenchymal Stem Cells into Insulin-Producing Cells

Islet-1(Isl1),a LIM homeodomain protein,is expressed in the embryonic pancreatic epithelium.As a key transcription factor,Isl1 can not only regulate insulin gene expression in normal glucose condition but also maintainβ-cell function and impact pancreaticβ-cell target genes.Some experiments have suggested that Micro RNA(miRNA)can play a critical role during the induction of insulinproducing cells(IPCs).However,it is unclear whether miRNA may regulate Isl1 expression during differentiation of human umbilical cord mesenchymal stem cells(HUMSCs)into IPCs.In this investigation,we induced HUMSCs into IPCs with a modified two-step protocol,activin A,retinoic acid(step1)and conophylline,nicotinamide(step2).To find the miRNA regulating Isl1 expression,we respectively used Target Scan,miRDB and RNAhybrid to predict and got the result,miR-128 and miR-216a.The miRNAs can inhibit Isl1 expression by dual luciferase assay.The results of real-time Polymerase Chain Reaction(PCR)showed that Isl1 expression level was almost reciprocal to that of miR-128 and miR-216a during differentiation of HUMSCs into IPCs.Furthermore,over-expression of miR-128 or miR-216a downregulated expression levels of Isl1 and Maf A.Therefore,miR-128 or miR-216a may regulate expression of islet-specific transcription factors to control differentiation of HUMSCs into IPCs.

基于动态主题网络的新兴技术主题识别——以氢燃料电池领域为例

[研究目的]新兴技术代表着未来的技术发展方向,是抢占科技前沿制高点必须把握的关键技术,准确识别新兴技术对国家发展具有重要战略意义。[研究方法]综合专利文本信息和分类信息,构建SBERT-LDA-IPC模型,识别各时间段的技术主题;根据主题相似度矩阵绘制动态主题网络,识别具有创新性和连续性的主题为候选主题,评估候选主题的新颖性和影响力,确定新兴技术主题;以氢燃料电池领域为例进行实证检验。[研究结论]研究表明,SBERT-LDA-IPC模型提高了主题聚类的连贯性和准确性,结合国家在氢燃料电池产业发布的系列政策作为验证依据,识别出的三个新兴技术主题,与国家政策制定和产业发展方向一致。

晚期缺血预适应(IPC)联合半乳糖凝集素-9通过上调调节性T细胞减轻小鼠肾脏缺血再灌注损伤

目的研究晚期缺血预适应（ischemic preconditioning,IPC）联合半乳糖凝集素-9（galectin-9,Gal-9）对小鼠肾脏缺血再灌注（ischemia reperfusion,IR）损伤的预防作用及可能的机制。方法 75只雄性C57BL/6N小鼠随机分为5组。（1）IR组：d1仅分离两侧肾蒂,不进行预缺血,d5夹闭两侧肾蒂造成缺血35min。（2）IPC-IR组：d1夹闭两侧肾蒂造成18min预缺血,d2~d5每天PBS皮下注射,d5给药后立即夹闭两侧肾蒂造成缺血35min。（3）IPC-Gal9-IR组：d1夹闭两侧肾蒂造成18min预缺血,d2~d5每天给予Gal-9 5μg皮下注射,并于d5给药后夹闭两侧肾蒂造成缺血35min。（4）IPC-Gal9-PC61-IR组：d1夹闭两侧肾蒂造成18min预缺血,d2~d5每天给予Gal-9 5μg皮下注射,d3和d5分别给予调节性T细胞（regulatory T cells,Treg）特异性拮抗剂PC61腹腔注射200μg,并在d5给药后夹闭两侧肾蒂造成缺血35min。（5）sham-sham组：不进行预适应,不给药,不给予IR损伤。以上5组于IR或第2次sham术后24h、72h和7天取样评价肾功能,并采用流式细胞术比较外周血、脾脏和肾脏中Treg的表达量和肾脏固有免疫系统反应程度及炎性因子的分泌。结果缺血再灌注24h及72h小鼠血肌酐IPC-IR组显著低于IR组（P〈0.01）,同时IPC-Gal9-IR组显著低于IPC-IR组（P〈0.05）,而给予Treg特异性拮抗剂的IPC-Gal9-PC61-IR组与IR组差异无统计学意义（P〉0.05）。缺血再灌注24h肾小管间质损伤指数IPC-IR组显著低于IR组（P〈0.05）,同时IPC-Gal9-IR组显著低于IPC-IR组（P〈0.05）。IPC-Gal9-IR组肾脏局部中心粒细胞浸润减轻（P〈0.05）且CD4＋T细胞分泌的IFN-γ减少（P〈0.05）。IPCGal9-IR组外周血、脾脏和肾脏Treg占CD4＋T细胞的比例较IR组显著升高（P〈0.05）。结论晚期IPC联合Gal-9干预对小鼠缺血再灌注肾损伤的保护作用优于单纯缺血预适应,可能与系统上调Treg表达有关。

Human umbilical cord mesenchymal stem cells derived from Wharton＇s jelly differentiate into insulin-producing cells in vitro

Background Islet transplantation is an effective way of reversing type Ⅰ diabetes. However, islet transplantation is hampered by issues such as immune rejection and shortage of donor islets. Mesenchymal stem cells can differentiate into insulin-producing cells. However, the potential of human umbilical cord mesenchymal stem cells （huMSCs） to become insulin-producing cells remains undetermined.Methods We isolated and induced cultured huMSCs under islet cell culture conditions. The response of huMSCs were monitored under an inverted phase contrast microscope. Immunocytochemical and immunofluorescence staining methods were used to measure insulin and glucagon protein levels. Reverse transcription-polymerase chain reaction （RT-PCR） was performed to detect gene expression of human insulin and PDX-1. Dithizone-staining was employed to determine the zinc contents in huMSCs. Insulin secretion was also evaluated through radioimmunoassay.Results HuMSCs induced by nicotinamide and β-mercaptoethanol or by neurogenic differentiation 1 gene （NeuroD1）transfection gradually changed morphology from typically elongated fibroblast-shaped cells to round cells. They had a tendency to form clusters. Immunocytochemical studies showed positive expression of human insulin and glucagon in these cells in response to induction. RT-PCR experiments found that huMSCs expressed insulin and PDX-1 genes following induction and dithizone stained the cytoplasm of huMSCs a brownish red color after induction. Insulin secretion in induced huMSCs was significantly elevated compared with the control group （t=6.183, P〈0.05）.Conclusions HuMSCs are able to differentiate into insulin-producing cells in vitro. The potential use of huMSCs in βcell replacement therapy of diabetes needs to be studied further

神经前体细胞不是胚胎干细胞向胰岛素分泌细胞分化的必经途径

探讨胚胎干细胞向胰岛索分泌细胞分化的途径，对胰腺组织工程的临床运用有重要意义。将胚胎干细胞在有小鼠胚胎成纤维细胞饲养层和白血病抑制因子的条件下培养扩增后，再将扩增后的胚胎干细胞不经过神经前体细胞阶段直接诱导为胰岛素分泌细胞，并与传统的多阶段诱导（经过神经前体细胞阶段）进行比较。结果发现，胚胎干细胞脱离饲养层细胞后，经过9～10d的分化诱导，可以分化为具有胰岛p细胞特征的胰岛素分泌细胞。与传统的多阶段诱导方法相比，诱导过程简化，诱导时间缩短，所得到的胰岛素分泌细胞数量无明显差异。说明胚胎干细胞向胰岛素分泌细胞分化存在多条途径。神经前体细胞阶段不是胚胎干细胞向胰岛素分泌细胞分化的必须途径。用传统的多阶段分化诱导法和直接诱导法都可以将胚胎干细胞诱导成胰岛素分泌细胞。

短梗霉素A对灰葡萄孢菌生长的影响

通过考察短梗霉素A(AbA)对灰葡萄孢菌野生株BcAUR1及其AUR1基因内含子缺失突变株BcAUR1a生长的影响,明确AbA抑制真菌生长的机理。AbA敏感性试验表明,低浓度AbA(8μg/mL)显著抑制野生株BcAUR1菌体的生长,高浓度AbA(50μg/mL)存在下观察不到BcAUR1的生长迹象。突变株BcAUR1a则不受AbA的影响,在低浓度和高浓度AbA存在下均能正常生长。AbA抑制BcAUR1侵染柑橘果实,但BcAUR1a在高浓度AbA存在下也能够有效感染柑橘果实。这两个试验均证实了突变株BcAUR1a具有AbA抗性。电镜观察表明,AbA引起BcAUR1细胞质膜和内膜系统形态异常,质膜和液泡膜断裂,细胞内物质泄露。AbA抑制灰葡萄孢菌生长的机制是由于IPC合成酶受到抑制,导致鞘磷脂类物质合成不足,细胞膜结构破坏,胞内物质外漏。

大鼠局灶性脑缺血耐受胶质细胞源性神经营养因子的表达

目的探讨局灶脑缺血预处理对大鼠大脑中动脉栓塞(MCAO)后神经功能的影响及胶质细胞源性神经营养因子(GDNF)的表达。方法线栓法建立大鼠MCAO及预处理模型,Bederson神经功能评分观察大鼠神经功能,免疫组织化学和原位杂交技术检测GDNF表达。结果缺血预处理(IPC)可提高大鼠局灶性脑缺血后神经功能,且梗死周边区GDNF蛋白及mRNA表达水平高于对照组(P<0.05)。结论10 min IPC可产生缺血耐受,可能通过增加GDNF的表达而起脑保护作用。

胰岛素产生细胞的诱导分化及微囊对其分泌能力的影响

目的探讨微囊对胰岛素产生细胞(insulin-producing cells,IPCs)分泌能力的影响。方法分离培养小鼠骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMMSCs)并传代纯化,应用大鼠胰腺提取物(rat pancreatic extract,RPE)对其进行诱导分化,诱导后的细胞随机分为微囊化组和未微囊化组。分别在1、2、3、4、5周等不同时间点,通过葡萄糖刺激实验,检测细胞的胰岛素与C肽释放情况。结果葡萄糖刺激实验结果显示,1周时微囊化IPCs与未微囊化的IPCs均能释放胰岛素,其量没有显著的差别;培养2周后未微囊化的IPCs胰岛素和C肽释放量开始下降,而微囊化IPCs胰岛素与C肽释放量在培养4周后才开始逐渐下降。结论微囊可延长IPCs的作用时间,有利于IPCs作用的发挥。

微囊化胰岛素产生细胞的胰岛素释放情况观察

目的微囊化后胰岛素产生细胞(IPCs)的分泌能力的观察。方法分离培养小鼠骨髓间充质干细胞(BMMSCs)并传代纯化,应用大鼠胰腺损伤提取物(RPE)进行诱导分化,诱导后的细胞随机分成微囊化组和未微囊化组;分别在1、2、3、5、10、15、20、25、30天对微囊化组、未微囊组及BMMSCs组进行胰岛素释放的检测。结果1、2、3、5天微囊化组和未微囊化组都有胰岛素释放并呈上升趋势,两组之间没有明显差异;10 d以后未微囊化组胰岛素释放量有下降的趋势,而微囊化组在第20天胰岛素的释放量开始下降,BM-MSCs组没有胰岛素的释放。结论微囊不会影响细胞的存活,并且能够延长细胞的存活时间和增加细胞的分泌能力。

脊髓薄片制备方法的改进及其脊髓Ⅱ板层神经元突触后电流的记录

目的探讨记录脊髓Ⅱ板层神经元兴奋性和抑制性突触后电流的方法。方法SD雄性大鼠,160～180 g,2%氟烷和100%氧气吸入麻醉后快速取腰段脊髓,迅速放入冰冷充氧的人工脑脊液,将约1 cm长的脊髓粘立于振动切片机载物台上,同时覆以冰冷的人工脑脊液进行横切片,片厚350～450μm,Kreb’S液提前30 min用95%CO2和5%O2预充氧,将切好的脊髓薄片转移其中,34～35℃孵育至少1 h后,以备实验记录用。结果在倒置显微镜下可清楚分辨出脊髓Ⅱ板层神经元。采用全细胞电压钳记录技术,给予选择性受体阻断剂以分离不同的突触后受体电流。在钳制电压为-70 mV时,可以记录到谷氨酸能的兴奋性突触后电流（EPSCs）;而在钳制电压为0 mV时,可以记录到抑制性突触后电流（IPSCs）。结论该方法为研究脊髓Ⅱ板层神经元递质释放提供了有效的途径。

SrTiO_3/α-Fe_2O_3异质结光阳极光电转换性能

作为一类重要的光电极材料,α-Fe2O3在太阳能转化方面有着潜在的应用前景。但是,光生电子空穴对的再复合导致α-Fe2O3的光电量子产率很低。为了抑制光生电子空穴对的再复合,提高α-Fe2O3的光电量子产率,采用Spin-coating方法在透明导电玻璃FTO(SnO2∶F)衬底上制备了SrTiO3/α-Fe2O3异质结薄膜光电极,并对该光电极进行了XRD、SEM、紫外-可见透射光谱的表征。在三电极光电化学测试系统中对薄膜的光电流-电压特性、入射光子电流转化效率(Incident photon to current efficiency,IPCE)对波长的依赖性进行了表征。在相同的Xe灯照射条件下,SrTiO3/α-Fe2O3异质结光电极的光电流及IPCE值大于单一的SrTiO3、α-Fe2O3各自的光电流及IPCE值,这与理论预测的结论一致。

缺血预处理减轻白细胞致肾急性缺血再灌注损伤的作用

采用家兔急性肾缺血再灌注损伤模型,研究缺血预处理(ischemic preconditioning,IPC)减轻白细胞致肾损伤的作用。实验分:IPC、缺血再灌注(inchemic reperfusion,IR)和对照组。均去右肾,检测在缺血前、缺血60min和再灌注60min、120min时混合静脉血中的白细胞总数和再灌120min时左肾系数(Left renal coefficient,LRC)、肾组织中的白细胞数以及过氧化脂质(Lipid peroxides,LPO)含量,并在光镜下对再灌120min时的肾小管的病理变化进行评分。结果表明:IR组在再灌注120min时,以上指标同对照组和IPC组比较,差异显著(P<0.05～0.01),血中白细胞数与LPO、LRC、肾小管评分的改变呈正相关(P<0.05),肾组织中白细胞数与LRC、肾小管评分呈正相关(P<0.05),IPC组肾组织中白细胞数显著低于对照组(P<0.01)。提示:白细胞在急性肾缺血再灌注损伤中是一个重要因素,IPC具有减轻白细胞所致的肾损伤作用。

热休克蛋白70在心肌保护中的作用

热休克蛋白70(HSP70)是生物体在应激原刺激下细胞内迅速增加的一组蛋白质,本文探讨了其生物学特性以及在心肌保护中的作用并指出了其应用前景。其对心肌的保护作用,体现在抑制细胞凋亡,与缺血预处理相关,减弱心肌缺血再灌注损伤,及减少心肌顿抑范围等方面。