低氧诱导因子及其低氧调节机制

低氧诱导因子(hypoxiainduciblefactor,HIF)是介导哺乳动物细胞适应低氧状况的核转录因子,由α和β亚基组成的异二聚体,其中α亚基受氧调节,是调节HIF活性的功能亚单位。目前已知HIF-1α的氧调节途径主要包括两种:常氧下VHL蛋白与氧依赖降解结构域羟化的Pro-564结合,介导HIF-1α的常氧下的泛素降解;常氧下天冬胺酰羟化酶使HIF-1αAsp-803羟基化,抑制其募集共刺激因子p300/CBP的作用,从而抑制其转录活性。此外,还包括PAS结构蛋白抑制因子等低氧调节途径。深入研究HIF的低氧调节机制,有利于认识缺血缺氧性疾病的发病机制。

VEGF和MMP-9在食管癌中的表达及低氧调节研究

目的本研究主要就食管癌表血管形成过程中MMP-9和VEGF的表达情况以及低氧的调节作用展开分析讨论。方法选择我院2011年2月至2012年2月所收治的56例食管癌患者作为研究对象,其中有42例患者手术标本中的MMP-9和VEGF表达采用逆转录-聚合酶链式反应法(RT-TCR)来进行检测,56例患者手术标本中的MMP-9和VEGF表达采用酶联吸附试验来进行测定,并用免疫组化染色法来对其MVD以及VEGF来进行测定。结果食管癌患者病灶部位的VEGF表达明显高于癌旁组织,且与肿瘤内的MVD呈正相关,VEGF阴性与VEGF阳性患者的平均MVD计数存在显著差异,具有统计血意义,P<0.05。其MMP-9的表达同样高于癌旁组织,但与患者的临床病理特征以及MVD计数无关,低氧可以增加VEGF的表达,但不会影响MMP-9的表达。结论在食管癌的形成以及转移过程中,VEGF表达起到了十分重要的作用,同时它还受到低氧的调节,将来可以将其作为抗血管治疗的靶点以及食管癌进展过程中的生物学指标。

VEGF和MMP-9在食管癌中的表达及低氧调节

目的 研究血管内皮生长因子 (VEGF)和基质金属蛋白酶 9(MMP 9)的表达与食管癌血管形成和临床的关系 ,以及低氧对其的调节作用。方法 用逆转录 聚合酶链式反应 (RT PCR)检测了42例食管癌手术标本 (包括 18例癌旁组织 )中VEGF和MMP 9mRNA的表达 ,用免疫组化染色的方法检测了 5 6例食管癌标本中VEGF蛋白的表达和平均血管密度 (MVD) ,同时用酶联免疫吸附试验(ELISA)的方法定量测定了低氧对食管癌细胞系中VEGF和MMP 9表达的影响。结果 食管癌中VEGF的表达显著高于癌旁组织 ,与肿瘤内平均MVD密切正相关 ,VEGF表达和肿瘤中MVD计数与食管癌的分期、淋巴结转移密切相关。食管癌中MMP 9的表达也显著高于癌旁组织 ,但MMP 9的表达与食管癌中的MVD计数和临床病理特征无关。低氧可以显著增加食管癌细胞系中VEGF的表达 ,但对MMP 9的表达无明显影响。结论 VEGF的表达可能在食管癌血管形成和转移中起重要作用 ,并受低氧调节 ,有可能作为反映食管癌进展的生物学指标和抗血管治疗的靶点。

口腔鳞癌中血管内皮生长因子和明胶酶-A的表达及低氧调节

目的 研究血管内皮生长因子 (VEGF)和明胶酶 -A(matrixmetalloproteinase -2 ,MMP -2 )的表达与口腔鳞癌血管形成和临床的关系 ,以及低氧对其调节作用。方法 应用SABC免疫组化染色的方法检测 40例口腔鳞癌手术标本中VEGF、MMP -2的表达和微血管密度 (MVD) ,用酶联免疫吸附实验 (ELISA )的方法定量测定了低氧对口腔鳞癌TSCCa细胞系和颈淋巴转移癌GNM细胞系中VEGF和MMP -2活性的影响。结果 口腔鳞癌中VEGF、MMP -2的表达显著高于正常口腔黏膜组织 ,与肿瘤内MVD密切正相关 (P <0 .0 5 ) ,VEGF、MMP-2表达和口腔鳞癌中的MVD计数与口腔鳞癌病理分级和临床分期无关 ,与口腔鳞癌颈淋巴结转移密切相关 (P<0 .0 5 )。低氧可以显著增加口腔鳞癌细胞TSCCa细胞系和颈淋巴转移癌GNM系中VEGF和MMP -2的活性。结论 VEGF和MMP -2的表达可能在口腔鳞癌血管形成和转移中起重要作用 ,并受低氧调节 ,VEGF与MMP -2可能具有某种内在联系 ,有可能作为反映口腔鳞癌侵袭转移的生物学指标和抗血管治疗的靶点。

线粒体运输蛋白HUMMR促进低氧环境中大鼠神经元轴突生长

目的:探讨低氧环境对神经元轴突生长的影响及低氧诱导的线粒体运输调节蛋白(HUMMR)在其中的作用。方法:将来源于SD大鼠的原代培养海马神经元放置在5%低氧培养箱中培养,利用免疫荧光染色方法观察神经元轴突生长情况,通过转染线粒体定位质粒pDsRed2⁃Mito观察神经元中线粒体运输,Western Blot检测HUMMR的表达情况。结果:在5%低氧暴露7 d后,低氧组神经元轴突长度显著高于对照组;神经元中线粒体轴突运输数量和速度都显著增多,尤其轴突逆向运输数量显著多于对照组;Western Blot显示HUMMR蛋白表达升高。结论:低氧环境培养可以促进神经元轴突生长,HUMMR蛋白表达增高,促进线粒体轴突逆向运输功能,可能是促进神经元轴突生长的重要机制之一。

不同温度下气调剂对常见储粮害虫控制效果研究

气调剂通过消耗有限空间内的氧气,对空间害虫有很好的控制效果。为了解不同温度下,气调剂对常见储粮害虫的杀灭效果,针对5种常见储粮害虫,研究了在20、25、30℃温度条件下,100 g气调剂在24000 cm^(3)密闭空间内对每种害虫死亡率与时间的关系,结果表明:在24000 cm^(3)密闭空间内,100 g气调剂3 d可使氧体积分数降至0.5%以下,且能维持氧体积分数≤0.5%,降氧迅速。随着温度的降低,相同时间下同种害虫的死亡率降低,其中,谷蠹和玉米象低温条件时LT_(99)值明显增大,表明2种蛀食性害虫对低氧和低温耐受能力较强。同一温度条件下,不同害虫对气调剂低氧环境下耐受力不同,玉米象耐受力最大,锯谷盗最低,5种害虫的低氧耐受力为:玉米象>谷蠹>长角扁谷盗>赤拟谷盗>锯谷盗。

Physiology of Cold Resistance of Amorpha fruticosa L. cv. Jinye

With two-year-old Amorpha fruticosa L. cv. Jinye and A. fruticosa as the research objects, the relative conductivity, MDA content, soluble sugar content, solu- ble protein content and proline content in leaf were determined during natural drop in temperature, and the SOD, POD and COD activity in leaf were determined under artificial low temperature to explore the adaptability of A. fruticosa L. cv. Jinye to low temperature. The results showed that with the decrease in natural temperature, the content of MDA in A. fruticosa L. cv. Jinye was lower than that in the control, and the contents of osmotic adjustment substances （soluble sugar, soluble protein and proline） increased, indicating that A. fruticosa L. cv. Jinye had a stronger toler- ance to low temperature compared with A. fruticosa. The activity of SOD, POD and CAT in A. fruticosa L. cv. Jinye increased continuously, higher than that in the con- trol, indicating that the resisting ability of A. fruticosa L. cv. Jinye against low tem- perature was superior to that of the control. There was no significant difference in relative conductivity between A. fruticosa L. cv. Jinye and A. fruticosa.

Upregulation of hypoxia inducible factor 1α mRNA is associated with elevated vascular endothelial growth factor expression and excessive angiogenesis and predicts a poor prognosis in gastric carcinoma

AIM： To investigate the implication of the hypoxia inducible factor HIF-1α mRNA in gastric carcinoma and its relation to the expression of vascular endothelial growth factor （VEGF） protein, tumor angiogenesis invasion/metastasis and the patient＇s survival. METHODS： In situ hybridization was used to examine expression of HIF-1α mRNA, and immunohistochemical staining was used to examine expression of VEGF protein and CD34 in 118 specimens from patients with gastric carcinoma. RESULTS： The positive rates of HIF-1α mRNA and VEGF protein were 49.15% and 55.92%, respectively. Positive expressions of HIF-1α and VEGF in stage T3-T4 tumors and those with vessel invasion, lymph node metastasis and distant metastasis were dramatically stronger than stage T1-T2 cases and those without vessel invasion, lymph node metastasis and distant metastasis. The mean microvascular density （MVD） in stage T3-T4 tumors and those with vessel invasion, lymph node metastasis and distant metastasis was significantly higher than stage T1-T2 tumors and those without vessel invasion, lymph node metastasis and distant metastasis. The mean MVD in tumors with positive HIF-1α and VEGF expression was significantly higher than that in tumors with negative HIF-1α and VEGF expression. The expression of HIF- 1α was positively correlated with VEGF protein. There were positive correlations between MVD and expression of HIF-1α and VEGF. The mean survival time and the S-year survival rate in cases with positive expression HIF-1α and VEGF and MVD value ≥ 41.5/0.72 mm^2 were significantly lower than those with negative expression of HIF-1α and VEGF and MVD value 〈 41.5/0.72 mm^2. CONCLUSION： Overexpression of HIF-1α is found in gastric carcinoma. HIF-1α may induce the angiogenesis in gastric carcinoma by upregulating the transcription of VEGF gene, and take part in tumor invasion and metastasis. They can be used as prognostic markers of gastric cancer in clinical practice.