碱性成纤维细胞生长因子对大鼠心肌保护机制研究

目的　在大鼠离体心肌缺血 -再灌注 (I/R)损伤模型上 ,观察碱性成纤维细胞生长因子 (bFGF)对心肌金属硫蛋白的影响 ,探讨bFGF心肌保护作用的可能机制。方法　复制大鼠离体心脏I/R损伤模型。预先2 4h应用bFGF ,以生理多导仪测定±dp/dtmax .[Cd10 9] 血红素饱和法测定心肌MT含量 ,硫代巴比妥法测心肌丙二醛 (MDA)含量 ,以自动生化分析仪测灌流液乳酸脱氢酶 (LDH)活性。结果　bFGF可诱导心肌MT生成 ,bFGF组心肌MT含量升高 ,MDA含量大于I/R组 ,灌流液乳酸脱氢酶 (LDH)及蛋白漏出明显减少 ,同时心功能明显改善。结论　MT参与了bFGF对大鼠离体心肌缺血 -再灌注 (I/R)损伤心肌保护作用。     

金属硫蛋白2A与心脑血管疾病的研究进展

近年来的研究发现,金属硫蛋白2A(MT2A)是一种重要的抗氧化应激分子。MT2A基因多态性与冠心病、动脉粥样硬化密切相关,它具有降低脑缺血再灌注损伤和保护心肌等作用,对心脑血管疾病的影响与其对炎症、氧化应激、细胞凋亡以及内皮功能等密切相关。文章主要综述MT2A与心脑血管疾病的关系及其影响机制。     

Influence of Isoflavones on Cadmium-induced Adverse Effects in Vascular Endothelial Cells （ECV 304）

To study the possible intervention of isoflavones in cytotoxicity induced by cadmium in vascular endothelial cells. Methods An ECV 304 cell line derived from human umbilical vein endothelial cells was adopted. Genistein / daidzein was added prior to or simultaneously with CdCl2, cell viability was determined by MTT assay, and metallothionein mRNA expression was monitored by RT-PCR method. Results Cell viability was higher in isoflavone and CdCl2. co-treated groups than that in CdCl2 treated group, with CdCl2 concentration at 10, 20, 40, and 80 μmol/L, respectively. However this increase was not observed in the group treated with CdCl2 at a concentration of 60 μmol/L, lsoflavones (10^-1mol/L to 10^-5 mol/L) were added 24 h before cells were challenged with 80 μmol/L CdCl2 for 24 h or simultaneously with 80 ^-10mol/L CdCl2. Genisteinincreased cell viability only at 10^-5 mol/L, while daidzein caused a dose-dependent increase from 10^-10 mol/L to 10^-5 mol/L in co-treatment with CdCl2. In pre-treatment, genistein (10^-7 to 10^-5 mol/L) increased cell viability whereas only 10^-5 mol/L of daidzein exerted protection. Apparent protection could be found when the cells were pre-treated with 10^-5 mol/L isoflavones for over 12 h, whereas 24 h incubation was required in such a co-treatment, with the exception of daidzein that had a significant protection in only 3 h. Isoflavones (10^-6 mol/L) incubated for 3 h to 24 h, increased MT ⅡA and MT IF mRNA expression, but the induction could not last for more than 24 h. Co-treatment with isoflavones could induce an additional induction of MT ⅡA mRNA expression in cells exposed to cadmium. However, the additional induction of MT ⅡA and MT IF mRNA was not seenwhen pre-treatment was carried out with isoflavones, with the exception of an increase in MT ⅡA mRNA expression in the daidzein pre-treated group. Conclusion Genistein/daidzein could reverse the cytotoxicity of cadmium either in pre-treatment or in co-treatment. The protection is the strongest in 10^-5 mol/L of isoflavones with a dose-dependent pattern. There are differences between genistein and daidzein in their protective effects. Whether the protection of isoflavones is related to their capacity of inducing MT mRNA expression remains to be elucidated.     

金属硫蛋白对全脑缺血再灌注后损伤神经的修复作用

目的:观察金属硫蛋白(Metallothionein,MT)外源性补充对大鼠全脑缺血再灌注(Cerebral ischemia and reperfusion,I/R)损伤的保护作用,并初步探讨其可能机制.方法:建立I/R模型,采用低血压并双侧颈总动脉夹闭的全脑缺血再灌注模型.缺血20min再灌注l d后,测行为学指标,石蜡切片HE染色观察海马神经元形态变化,并用免疫组化方法检测海马神经生长因子-β(Nerve growth factor-β,NGF-β)的表达.结果:MT脑室注射给药(1.4、4.2mg/kg)能剂量依赖性的减轻大鼠行为学症状,增加大鼠海马神经元NGF-β的表达(0.46、1.4、4.2 mg/kg).同时病理组织学观察还发现,MT(0.46、1.4、4.2 nv,/kg)能显著减少I/R大鼠海马区神经元的固缩,增加存活细胞的数量,减轻脑损伤.结论:MT对脑缺血再灌注损伤有神经保护作用,可能机制为促损伤神经元修复.     

In silico prediction of potential metallothioneins and metallohistins in actinobacteria

Metallothioneins and metallohistins are short peptides with a high cysteine and/or histidine content able to coordinate metals intracellularly, thereby increasing the tolerance against elevated concentrations of metals. Because of their features, they can be detected by in silico prediction from proteomes annotated from sequenced genomes. Here, we analyzed 73 sequenced actinobacterial genomes for peptides (≤ 100 amino acids) with a high content of cysteine and histidine (≥ 15%) and identified 103 putative metallothioneins and metallohistins. For 45 of these peptides, we found similarities to metal binding protein domains, including zinc fingers, heavy metal transporters or eukaryotic metallothioneins, which can serve as proof-of-principle in underscoring a potential function as metal binding peptides. An evolutionary origin from metal containing domains of enzymes is discussed and metallohistins not containing cysteine are described for the first time for bacteria.     

金属硫蛋白在非小细胞肺癌中的表达及其与预后的关系

目的探讨非小细胞肺癌（NSCLC）组织中金属硫蛋白(metallothionein,MT)的表达及临床意义。方法采用免疫组织化学SP法检测68例NSCLC和25例肺良性疾病中MT的表达,分析其与NSCLC临床病理特征、预后以及耐药蛋白GST-π和TopoⅡ表达的关系。结果MT在NSCLC组织中表达显著高于肺良性病变组织(P<0.05),与年龄、分化程度有关;MT表达患者术后生存期明显短于不表达者。MT表达和GST-π、TopoⅡ表达无相关性(P>0.05)。结论MT在NSCLC组织中存在不同程度的高表达,且与某些生物学行为有关,可以作为评价预后的指标。     

金属硫蛋白对镍致小鼠肝损伤的保护作用

目的探讨金属硫蛋白对镍致小鼠肝损伤的保护作用及其机制。方法利用硫酸镍染毒复制小鼠肝损伤的模型,然后腹腔注射不同剂量的金属硫蛋白7 d,检测肝脏器系数、肝功能及肝组织脂质过氧化等指标,并行肝组织病理学观察。结果肝损伤模型组与金属硫蛋白(MT)保护组小鼠肝脏器系数差异有统计学意义(P<0.05),随着MT剂量的增加,肝脏器系数逐渐降低(P<0.05);MT保护组肝细胞炎性浸润、水肿及坏死明显减轻,肝窦结构有恢复;MT保护组小鼠血清AST、ALT、GGT及总胆汁酸均低于损伤模型组(P<0.05),肝组织MDA、GSH低于损伤模型组(P<0.05),而SOD、GSH-Px活性则高于损伤模型组(P<0.05),并均有较强的剂量依赖关系。结论金属硫蛋白对镍致小鼠肝损伤有保护作用,保护机制可能与减轻氧化损伤有关。     

Distribution of metallothionein in normal and pathological human skin

The expression and distribution of metallothionein (MT) in frozen sections of normal and pathological human skin was studied using the monoclonal antibody L2E3 directed against MT derived from human fetal liver. Immunohistochemical staining of normal fetal and adult skin revealed strong reactivity in basal keratinocytes of epidermis and outer hair root sheath, hair matrix cells and the secretory coil, but not the exocrine portion of eccrine glands; myoepithelial cells around apocrine sweat glands were similarly stained. In epidermal hyperplasia, variable numbers of suprabasal keratinocytes were stained, whereas in interface dermatitis, interrupted staining was found in the basal layer. Weak or scattered staining was observed in squamous tumours, whereas basal cell carcinomas did not show consistent staining. The distribution of MT in normal skin was in line with the germinative role of basal keratinocytes and hair matrix cells, whereas its distribution in hyperplastic epidermis was in line with experimental animal data, and reflected the increase in the germinative pool in these conditions. It is concluded that monoclonal antibody L2E3 may serve as a valuable immunohistochemical marker in diagnostic cutaneous pathology since it labels basal keratinocytes selectively, and since it discriminates between eccrine and apocrine sweat glands.     

The prognostic value of the expression of collagenase IV, cathepsin D and metallothionein in squamous cell carcinomas of the skin determined by immunohistochemistry

Abstract  We analyzed 53 specimens from primary squamous cell carcinomas of the skin for the expression of collagenase IV, cathepsin D and metallothionein by means of immunohistochemistry along with histological data. We compared tumors that metastasized (30) with tumors that did not (23) during a follow-up period of at least 5 years. The expression of the two proteolytic enzymes cathepsin D and collagenase IV was also assessed at the invading front of the tumors. Statistical analyses revealed significant differences for the overall expression of cathepsin D (P < 0.05), expression of cathepsin at the invading front (P < 0.05) and the tumor thickness (P < 0.01). The results showed that cathepsin D may be a prognostic factor for squamous cell carcinomas of the skin. We then combined the results of parameters with statistically significant differences by multiplication. The prognostic value of such a combined risk-factor score showed higher confidence than any of the single parameters alone: a sensitivity of 63.3%, a specificity of 87.0% and an efficiency of 73.6%. This kind of combined risk-factor score might be used to more accurately detect patients at high risk of metastasis. Received: 16 June 2000 / Revised: 1 September 2000 / Accepted: 10 December 2000     

大鼠慢性酒精性脑损害及额区MDA、MT含量变化的研究

目的观察慢性酒精性脑损害大鼠额区脑组织丙二醛、金属硫蛋白含量变化情况。方法通过逐步增加浓度自由饮方法建立慢性酒精性脑损害大鼠动物模型。观察大鼠额区脑组织的形态学改变,测定脑组织中MOD、MT水平。结果酒精组额区脑组织有神经细胞数目缺失及细胞变性和损伤,酒精组MDA含量显著升高,MT含量显著降低,与对照组比较差异有统计学意义(P<0.01)。结论长期摄入大量酒精可使脑组织氧自由基代谢失衡,MDA含量升高,MT含量降低。