HAIR CELL-LIKE CELL GENERATION INDUCED BY NATURE CULTURE OF ADULT RAT AUDITORY EPITHELIUM

Objective To establish adult rat auditory epithelial cell culture and try to find precursor cells of auditory hair cells in vitro. Methods With refinement of culture media and techniques, cochlear sensory epithelial cells of adult rat were cultured. Immunocytochemistry and Bromodeoxyuridine （BrdU） labeling were used to detect properties and mitotic status of cultured cells. Results The cultured auditory epithelial cells showed a large, flat epithelial morphotype and expressed F-actin and cytokeratin, a subset of cells generated from auditory epithelium were labeled by calretinin, a specific marker of early hair cell. Conclusion Adult rat auditory epithelium can be induced to generate hair cell-like cells by nature culture, this phenomenon suggests that progenitor cells may exist in rat cochlea and they may give birth to new hair cells. Whether these progenitor cells are tissue specific stem cells is still need more study.     

siRNA directed against TrkA sensitizes human pancreatic cancer cells to apoptosis induced by gemcitabine through an inactivation of PI3K/Akt-dependent pathway

Pancreatic cancer is a lethal disease.Despite sig-nificant advances in diagnosis,staging,and surgicalmanagement of the disease,less than10%of pa-tients survive for more than one year fromthe ti meof diagnosis[1-2].The largely refractory response tochemotherapy is a common feature of this disease,and eventhe principal therapeutic agent,the nucleo-side analogue gemcitabine(2′,2′-difluorodeoxycyt-idine),only marginally affects clinical outcomes[3].Therefore,further understanding of the chemores…     

体外观察紫杉醇对人胆管癌细胞QBC939凋亡的诱导作用

目的观察微管稳定剂紫杉醇对胆管癌QBC939细胞的作用。方法MTT法检测紫杉醇对QBC939细胞的抑制作用;光镜和电镜观察紫杉醇作用后细胞形态的变化;流式细胞仪分析细胞周期的改变。结果随着药物作用时间的延长及浓度的增加,紫杉醇对QBC939细胞的增殖抑制作用就越明显。形态学及流式细胞仪分析显示S期及G2/M期阻滞和细胞凋亡。结论紫杉醇诱发的人胆管癌细胞的凋亡与细胞DNA合成期及分裂期阻滞密切相关。这一作用机制将为临床治疗提供理论依据。     

双侧多导联记录大鼠脑三叉神经诱发电位的研究

目的探讨双侧多导联记录在脑三叉神经诱发电位实验中运用的可行性及正常值。方法采用不同刺激波宽的电刺激,双侧多导联记录大鼠脑三叉神经诱发电位。结果不同时间的实验刺激(RUN1和RUN2),各个相应波潜伏期无明显差异(P>0.05)。左右两侧各个相应波潜伏期中,RUN2-T1-C2(0.04 ms)和RUN1-T1-C3(0.1 ms)两组有明显差异(P<0.05),其余各组均无明显差异(P>0.05)。电刺激波宽为0.04 ms时各波的标准差多小于电刺激波宽为0.1 ms时各波的标准差。结论该方法具有较好的稳定性和可重复性,采用同体双侧对比实验时,建议使用0.04 ms的电刺激波宽。     

硒对离体人胚肝细胞膜的保护作用

在原代培养人胚肝细胞脂质过氧化损伤模型上，观察硒对肝细胞膜流动性及膜表面超微结构的影响。结果：预加硒可有效地维持肝细胞膜流动性，保护膜表面结构完整。硒保护组培养液中谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性明显增加，丙二醛（ＭＤＡ）水平下降，与损伤组比较有显著性差异（Ｐ＜０．０１）。且其ＧＳＨ－Ｐｘ／ＭＤＡ比值与膜流动性增加呈正相关。提示上述硒的保护作用与增强细胞抗氧化能力有关。     

犬肝胆细胞缺血性损伤的定量分析

杂交犬２３条，按自体原位肝移植模型的手术方法，在灌注前、后及肝动脉缺血１ｈ分别取标本，进行电镜观察，并通过自动图像分析仪测算肝胆细胞线粒体的平均光密度、平均面积、平均体积、平均周长及形态系数。结果显示，灌注后上述各种参数与正常值相比无显著性差异，肝动脉缺血１ｈ，其几何参数较正常值有明显差异（Ｐ＜０．００１）。本实验通过细胞线粒体超微结构的病理变化定量地说明肝动脉缺血对肝脏尤其是胆道系统的影响，比较准确地和客观地说明肝动脉对肝胆系统的重要地位，为今后肝移植手术中充分认识肝动脉的重要性提供了可靠的理论依据。     

醛固酮及螺内酯对肝星状细胞中TIMP-1和MMP-2mRNA表达的影响

目的观察醛固酮及螺内酯对活化的肝星状细胞(HSC-T6)作用后不同时间段MMP-2和TI MP-1 mRNA的表达情况。方法采用RT-PCR的方法测定HSC-T6中MMP-2、TI MP-1 mRNA的表达。结果活化的HSC可表达MMP-2及TI MP-1的mRNA。醛固酮组MMP-2、TI MP-1的mRNA在48、72 h表达均高于对照组,在作用24、48、72 h时MMP-2、TI MP-1的mRNA的表达随时间递增。而螺内酯组则相反。醛固酮加螺内酯组与单加醛固酮组相比MMP-2、TI MP-1的mRNA表达下降。结论醛固酮可能通过促使MMP-2及TI MP-1 mRNA的表达促纤维化,螺内酯可抑制这一作用。     

肝动脉桥式置管转流对供肝及胆道组织细胞凋亡的保护作用

目的验证肝动脉桥式置管转流这一方法是否能够减轻肝动脉缺血(hepatic artery ischemia,HAI)引起的肝胆细胞凋亡。方法应用简易犬肝自体原位移植模型,将24只杂交犬随机分为肝动脉缺血组(HAI组,8只)、肝动脉桥式置管转流组(TBB组,8只)及对照组(8只)。在制模后,3组动物均于冷灌注后不同时点切取肝脏、胆道组织,分别用戊二醛及40 g/L多聚甲醛溶液固定,进行电镜观察和TUNEL染色,观察肝胆组织形态学改变及细胞凋亡情况,并计算两组的凋亡指数。结果在冷灌注后2 h,HAI组电镜下出现较明显的肝胆细胞凋亡现象;肝动脉桥式置管转流组肝胆细胞凋亡现象少见;对照组难以找到凋亡肝胆细胞。TUNEL法染色切片显示,冷灌注后3组肝胆组织内均有少量凋亡细胞,其凋亡指数相差不大(P>0.05);随冷灌注后时间的延长,3组凋亡细胞的数量均有所增加,但HAI组凋亡指数的升高更为显著,肝动脉桥式置管转流组次之,对照组变化不大,3组间差别有统计学意义(P<0.01)。结论肝动脉桥式置管转流对肝移植时肝动脉缺血所导致的肝胆细胞凋亡具有显著保护作用,应在继续完善改进的基础上实施于临床。     

汉黄芩素对脂多糖诱导的促炎性因子的影响

目的探讨汉黄芩素对脂多糖(LPS)诱导的小胶质细胞激活时所分泌的促炎性因子的影响。方法采用LPS诱导的小胶质细胞活化模型,用ELISA法测定细胞外液所分泌的一氧化氮(NO)、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)的含量。结果LPS能激活小胶质细胞,并且能使其NO、TNF-α和IL-6的分泌量增加,汉黄芩素浓度为20-30μmol/L时能有效降低NO、TNF-α和IL-6的含量。结论汉黄芩素有抑制促炎性因子分泌的作用。     

The development of an OxyHb animal model in mice and the study on OxyHb-induced apoptosis of mouse brain cells in vivo

Objective On the basis of developing a new animal model for oxyhemoglobin (OxyHb) injection into subarachnoid space in mice, this research was to explore the temporal dependence and spatial distribution of OxyHb- induced apoptosis in the mouse brain cells in vivo and the mechanism of neurocyte injury induced by OxyHb. Methods The animal model for OxyHb injection into subarachnoid space in mice was developed. Mice were divided randomly into the experimental group (n=40) and the control group (n= 35). The control group received saline injection (50 μL ) and the experimental group received OxyHb injection (50 μL ), both into the subarachnoid space. The mice of the two groups were subdivided according to different postoperative time (3 h, 6 h, 12 h, 24 h and 48 h). The apoptosis or necrosis of cells was distinguished with microscopy (HE staining), transmission electron microscopy and TUNEL method. Results The distribution of apoptosis was mainly in the ipsilateral neocortex and bilateral hippocampal gyrus. The apoptotic mouse brain cells showed morphological changes in the experimental group by HE staining and transmission electron microscopy. The count of TUNEL-positive cells showed substantial increase in the experimental group, and there was a significant difference between the control and experimental groups, and the number of OxyHb- induced apoptotic cells decreased with time. Conclusion OxyHb in subarachnoid space in mice can induce apoptasis, but not necrosis of mouse brain cells in viro. The apoptotic brain cells show the pattern of temporal dependence and spatial distribution. It is suggested that the early treatment should be the method of first choice for treating the hemorrhagic brain injury.