Indian Hedgehog信号通路在软骨细胞成熟及转分化过程中的调控作用

目的 探究Indian Hedgehog（IHH）信号通路对软骨内成骨过程中软骨细胞成熟以及转分化的影响。方法 取10日龄野生型小鼠的胫骨组织,采用原位杂交和免疫组织化学染色检测生长板区域IHH信号通路相关分子Ihh、Ptch1和Gli1的表达水平。构建肥大软骨细胞特异性Ihh基因敲除小鼠（Col10a1^Cre/+; Ihh^null/C）,并采用影像学检查和阿利新蓝染色评估该小鼠的骨骼发育状况。构建肥大软骨细胞IHH信号通路持续激活小鼠（Col10a1^Cre/+; R26Smo^M2/M2和 Col10a1^Cre/+; Ptch1^LacZ/C）,采用HE染色、原位杂交和TUNEL染色分别对受精15.5天胎鼠胫骨组织形态结构、Ihh（肥大软骨细胞分子标志物）和Col1a1（成骨细胞分子标志物）以及肥大软骨细胞凋亡水平进行检测;另外应用HE染色对10日龄小鼠的胫骨组织进行组织学分析。结果 肥大软骨细胞合成分泌IHH,但不表达Ptch1和Gli1。抑制肥大软骨细胞合成IHH蛋白会导致出生后小鼠出现侏儒症;X线检查结果显示小鼠出现严重的骨骼发育不良,包括胸廓狭小、球形头骨以及椎骨发育异常等表现。持续启动IHH信号通路时,胚胎早期软骨细胞成熟分化过程虽未见异常,但是出生后小鼠的骨小梁、骨内膜以及皮质骨等结构均出现一定的异常表现。结论 IHH信号通路虽然不参与肥大软骨细胞的终末分化过程,但在软骨细胞转分化的过程中起到了重要的调控作用。     

Skeletal muscle stem cells do not transdifferentiate into cardiomyocytes after cardiac grafting

Skeletal muscle cell-derived grafts in the heart may benefit myocardial performance after infarction. Several studies have suggested that skeletal muscle stem cells (satellite cells) from adult muscle undergo transdifferentiation into cardiomyocytes after grafting into the heart, but expression of cardiac markers in graft cells has not been rigorously confirmed. To determine the fate of satellite cell-derived grafts in the heart, adult rat satellite cells were tagged in vitro with bromodeoxyuridine (BrdU) and grafted into normal hearts of syngeneic rats. At 4 and 12 weeks the graft cells formed multinucleated, cross-striated myofibers that expressed fast skeletal myosin heavy chain (MHC), thus indicating a mature skeletal muscle phenotype. Double staining for the BrdU tag and cardiac-specific markers was employed to identify transdifferentiation. Aside from four questionable cells, none of the 11 grafts examined expressed alpha-MHC, cardiac troponin I, or atrial natriuretic peptide. At 4 weeks, grafts expressed beta -MHC, a hallmark of slow twitch myofibers. By 12 weeks, however, the myofibers had atrophied and downregulated beta-MHC. Grafts never expressed the intercalated disk proteins N-cadherin or connexin43, hence electromechanical coupling did not occur. In conclusion, satellite cells differentiate into mature skeletal muscle and do not express cardiac-specific genes after grafting into the heart. Thus, transdifferentiation into cardiomyocytes did not occur.     

Transdifferentiation between bone and fat on bone metabolism

The transdifferentiation of bone and fat is a new insight in studying the increasingly bone marrow fat in the process of osteoporosis of elderly or menopause crowd which is increasing in prevalence. The loss of bone mass in osteoporosis is multifactorially determined and includes genetic, hormonal and environmental determinants. Although it has long been considered whether the transdifferentiation process does exist in vivo and whether it could be find in the same individual, interaction between skeleton and adipose tissue has been proved pre-clinically and clinically by increasing evidence. Here we focus on the current understanding of the transdifferentiation between bone and fat, the molecular interactions and future clinical implications of recent studies linking the transdifferentiation to bone metabolism diseases. Furthermore, a set of recommendations of bone and fat transdifferentiation on bone metabolism are also presented to facilitate evaluation of this magic process.     

辛伐他汀对大鼠肾小管上皮细胞转分化的作用

目的:观察辛伐他汀对实验性1型糖尿病大鼠肾小管上皮细胞转分化的作用。方法:将实验动物随机分为对照组、糖尿病组及治疗组。治疗组给予辛伐他汀[5 mg/(kg.d)]治疗12周。于实验第6,9,12周检测24 h尿蛋白(24 h TP),12周检测血清肌酐(Scr),内生肌酐清除率(Ccr)和NAG酶。采用免疫组织化学技术检测各组肾小管间质中-αSMA,MCP-1,CD44表达水平。结果:糖尿病大鼠肾组织中-αSMA,MCP-1和CD44表达较对照组明显增加(P<0.01),治疗12周后,辛伐他汀可明显降低1型糖尿病肾病大鼠肾小管间质中-αSMA,MCP-1和CD44表达(P<0.01),并降低蛋白尿(P<0.01),改善肾功能各指标及肾组织病理学损害。-αSMA表达分别与MCP-1,CD44表达及24 hTP呈正相关(r=0.998 5,0.976 3,1.000 0,P<0.01)。结论:辛伐他汀对糖尿病肾小管间质病变具有保护作用,其机制至少部分与抑制肾小管上皮细胞转分化,下调肾小管间质中-αSMA,MCP-1和CD44表达有关。     

成人胰腺干细胞转分化为胰岛细胞过程中的形态学观察

目的：观察成人胰腺干细胞转化化为胰岛过程中的形态学变化，以便更深入了解有关机制。方法：人胰腺组织经胶原酶消化后，用梯度离心法将胰腺外分泌细胞和胰岛分离，混于外分泌组织中的导管上皮细胞即具有转分化潜能的干细胞。在体外经CMRL1066及不含血清的DMEM／F12加多种营养因子的培养液中培养27d，在培养的不同时间点取细胞作PDX－1、CK－19等单抗的免疫组化染色。光镜和电镜观察不同时间点的形态学变化。结论：上述方法可获得大量以往在胰岛分离时丢弃的胰腺导管上皮细胞。经体外一定条件的培养后，其形态学变化过程为：导管上皮细胞迅速分裂增殖转变为有分化能力的干细胞继而转分化为胰岛细胞。结论：成人胰腺的导管上皮具有干细胞潜能，并可在体外转分化为大量具有内分泌功能的胰岛。用此方法获得大量的胰岛可能为克服胰岛移植的供体短缺提供一条新的途径。     

核因子κB反义寡核苷酸对转化生长因子β1诱导人肾小管上皮细胞转分化的影响

目的 探讨在转化生长因子β1（TGF-β1）诱导下，核因子κB（NF-κB）反义寡核苷酸对体外培养的人肾小管上皮细胞（HK-2）转分化的影响。 方法 采用脂质体介导的方法将NF-κB反义寡核苷酸（AS-ODN）导入细胞，以TGF-β1（10 μg/L）刺激HK-2细胞24 h后，用RT-PCR方法检测细胞中NF-κB mRNA及α平滑肌肌动蛋白（α-SMA）mRNA表达，用荧光光谱法分析α-SMA蛋白的表达，并以倒置相差显微镜观察细胞转分化过程的形态变化。 结果 TGF-β1诱导24 h后，HK-2细胞中NF-κB mRNA的表达显著上调，为空白对照组的8倍以上（P < 0.01）。NF-κB反义寡核苷酸导入细胞后，可显著抑制TGF-β1诱导的HK-2细胞的 NF-κB mRNA表达，比TGF-β1组减少75％（P < 0.05），同时，α-SMA mRNA和蛋白表达亦较TGF-β1组均明显下调（P < 0.05）。 结论 NF-κB反义寡核苷酸可抑制TGF-β1诱导肾小管上皮细胞NF-κB的表达，抑制肾小管上皮细胞转分化，可能有利于肾间质纤维化的防治。     

低密度脂蛋白和氧化低密度脂蛋白诱导人肾小管上皮细胞转分化的通路研究

目的探讨低密度脂蛋白（LDL）和氧化（OX）LDL是否可诱导人肾小管上皮细胞转分化及其可能机制。方法体外培养的第2代肾小管上皮细胞随机分为（1）阴性对照组；（2）LDL（50mg／ml）组；（3）oxLDL（50mg／ml）组；（4）LDL（50mg／m1）＋PD98059（5μmol／L）组；（5）oxLDL（50mg／ml）＋PD98059（5μmol／L）组。应用形态学、免疫荧光、Western印迹观察LDL和oxLDL刺激小管细胞角蛋白（cytokerafin）、E-钙粘糖蛋白（cadhefin）、α-SMA和波形蛋白（vimenfin）表达的改变、Ⅰ型胶原产生的改变，及其与ERK1／2MAPK通路活化的关系。结果OXLDL较LDL有更强的致小管上皮细胞转分化的作用，与对照组相比。细胞中上皮细胞标记cytokeratin和E-cadherin表达减少，间充质细胞标记α-SMA和vimentin明显增加，Ⅰ型胶原产生增多（P〈0．05）。LDL和oxLDL刺激组细胞中ERK1／2MAPK和GSK-3β磷酸化活化较对照组明显增强（P〈0．05）；β-catenin发生细胞核内转移。MAPK抑制剂PD98059可抑制GSK-3β的磷酸活化，并几乎完全阻断oxLDL诱导的肾小管上皮细胞转分化，但对LDL诱导的小管上皮细胞转分化只有部分阻断作用。结论本研究首次在体外观察到（1）oxLDL可诱导肾小管细胞上皮细胞转分化和Ⅰ型胶原的产生，作用明显强于LDL；（2）ERK1／2MAPK、GSK-3β和β-catenin组成一条信号通路调节LDL和oxLDL诱导的小管上皮细胞转分化。     

糖尿病小鼠胰腺干细胞转分化为胰岛样细胞

目的 观察链脲佐菌素所致糖尿病小鼠胰腺干细胞是否能转分化为胰岛样细胞.方法 以链脲佐菌素建立糖尿病小鼠模型,分离培养其胰腺导管上皮细胞,经体外扩增及诱导培养后,以细胞免疫化学方法检测PDX1表达,行STZ染色和葡萄糖刺激的胰岛素释放试验鉴定其功能.结果 糖尿病小鼠胰腺干细胞经体外培养和诱导分化后,PDX1阳性,并形成胰岛样细胞团;胰岛样细胞对高糖刺激(15.0 mmol/L)的胰岛素释放较低糖(5.6 mmol/L)时增加了1.4倍(37.2±11.2比25.9±7.6,t =2.830,P＜0.05),DTZ染色阳性.结论 链脲佐菌素所致糖尿病小鼠胰腺干细胞在体外培养条件下可转分化为胰岛素分泌细胞.     

Petrous Apex Cholesteatoma

Primary or secondary petrous apex cholesteatoma requires surgical management. We describe here five patients with cholesteatoma in the petrous apex on whom different surgical approaches to this region were used. Translabyrinthine-transcochlear (transotic) approach with VII-XII anastomosis was used in four patients. In one patient middle fossa approach with otic capsule and facial canal leaving intact was used. All patients are without recurrence of cholesteatoma with improving of the facial nerve function in one case. We discuss specific pathologies of the petrous apex, the surgical approach to this region indicated according to the size and type of pathology diagnosed, hearing loss and facial nerve function. Possible complications of this surgical procedure and their management are also discussed.     

成人胰腺干细胞转分化为胰岛的研究

目的：通过对成人胰腺干细胞转分化为胰岛过程的研究以便更深入了解及改进胰腺干细胞分离、培养、鉴定方法。方法：成人胰腺组织经胶原酶消化后,用密度梯度离心法将胰腺外分泌细胞、导管上皮细胞和胰岛分离、纯化,导管上皮细胞即具有转分化潜能的干细胞,在体外先后以CMRL1066和无血清DMEM／F12培养液共培养27d,在培养的不同时间点取样本于光镜和电镜下观察细胞形态学变化及干细胞特异性转录基因PDX－1,CK－19蛋白等单抗的免疫组化染色,并测定培养液中的淀粉酶和胰岛素含量。结果：上述方法可获得大量以往在胰岛分离时丢弃的胰腺导管上皮细胞。经体外一定条件的培养后,第1天即可见PDX－1,CK－19阳性细胞,胰腺导管上皮细胞迅速分裂增殖并转变为有分化能力的干细胞继而转分化为三维结构的胰岛细胞。培养27d后,平均每克胰腺组织可生成760个胰岛。结论：成人胰腺的导管上皮具有干细胞潜能并可在体外转分化为大量具有内分泌功能的胰岛,用此方法获得大量的胰岛可能为克服胰岛移植的供体短缺提供一条新的途径。