褪黑素和6-羟褪黑素保护神经细胞抗缺血再灌注损伤比较研究

目的研究褪黑素(Mel)和6-羟褪黑素(6-OHMel)神经保护作用及作用机理。方法体外培养N2a细胞,模拟缺血再灌注(OGSD),加入Mel和6-OHMel,检测以下指标:①细胞生存能力:MTT法、乳酸脱氢酶释放;②细胞凋亡分析:DNA片断化,细胞色素C,Caspase3活性;③活性氧(ROS)和线粒体跨膜电位。结果①Mel和6-OHMel都能减轻OGSD诱导的N2a细胞损伤,Mel的作用强于6-OHMel。②Mel和6-OHMel均能抑制细胞色素C释放,但6-OHMel强于Mel。③Mel和6-OHMel都能稳定线粒体跨膜电位,但Mel作用时间比6-OHMel长。④Mel和6-OHMel能清除ROS,6-OHMel表现为直接作用,Mel表现为间接作用。⑤Mel和6-OHMel均能抑制caspase3的活性,但是作用时间不同。6-OHMel表现在OGSD后12h,Mel在OGSD后24h。结论Mel和6-OHMel的神经保护作用与其抗氧化、稳定线粒体功能相关,Mel的作用机制更复杂。     

蛋白激酶C在软脂酸诱导HepG2细胞胰岛素抵抗中的作用

目的从蛋白激酶C(PKC)信号通路角度,探讨游离脂肪酸(FFA)引起肝脏胰岛素抵抗(IR)的可能机制。方法培养HepG2细胞,同时设立对照组、软脂酸(PA)组、高胰岛素组。软脂酸组、高胰岛素组分别用250μmol/L PA、5×10-7mol/L胰岛素处理24h。然后对照组、软脂酸组再根据胰岛素刺激前加( )与不加(-)PKC抑制剂白屈菜红碱盐酸盐(chelerythrine chloride,CC)5μmol/L预处理1h,随机分为两亚组:对照组(-)、对照组( )、PA组(-)、PA组( )。葡萄糖氧化酶法测定胰岛素刺激后12h葡萄糖消耗量,蒽酮法测定胰岛素刺激后3h点细胞内糖原含量,Western blotting技术检测15min点细胞内P-Ser473PKB、P-Ser21/9GSK-3α/β水平。结果PA组(-)与高胰岛素组葡萄糖消耗量无统计学差异(P=0.523)。葡萄糖消耗量、细胞内糖原含量、P-Ser473PKB、P-Ser21GSK-3α、P-Ser9GSK-3β水平均显示,PA组(-)与对照组(-)比较显著降低(P值依次为0.000,0.000,0.004,0.004,0.028),对照组( )与对照组(-)比较略有升高但无显著性差异;PA组( )与PA组(-)比较显著升高(P值依次为0.000,0.014,0.043,0.041,0.035)。结论PA(250μmol/L)体外成功诱导了HepG2细胞产生IR,PKC信号通路在FFA引起肝脏IR中起着重要作用。     

花生四烯酸对游离脂肪酸诱导肝细胞胰岛素抵抗的缓解作用研究

目的：探讨游离脂肪酸（FFA）诱导肝细胞胰岛素抵抗及花生四烯酸（从）在软脂酸（PA）诱导的肝细胞胰岛素抵抗中的作用。方法：分别用不同浓度的PA和从与HepG2细胞共同培养不同的时间，并设立正常对照组（Coatrol组）。采用葡萄糖氧化酶法测定培养液中的葡萄糖浓度，蒽酮法测定细胞内糖原含量以确定HepG2细胞产生胰岛素抵抗程度．结果：1．0．25mmol／L PA组中的葡萄糖浓度高于Control组和PA＋AA（20umol／L）组（P〈0．05），糖原含量低于Control组和PA＋从（20umol／L）组（P〈0．05）。2，PA从（20umol／L）组与0．25mmol／L PA组比较，PA＋AA（50umol／L）组与Control组比较，葡萄糖浓度和糖原含量变化有显著意义（P〈0．05）。结论：高浓度的PA可以诱导肝细胞产生胰岛素抵抗，并呈现剂量依赖性；一定浓度的从能够缓解PA引起的胰岛素抵抗。     

大学新生心理健康与自我和谐关系

有研究表明[1].大学生心理健康水平低于全国正常人群,心理障碍检出率达20.72%.提示加强大学生心理健康教育的必要性和紧迫性.而大学新生处于大学适应的过渡期和关键期.为了解大学新生心理健康与自我和谐之间关系,为大学生的心理健康教育与辅导提供依据进行了本研究.     

太原市小学生伤害相关危险行为现况调查

目的了解太原市小学生伤害相关危险行为现状,为进行有效干预提供科学依据。方法对太原市6城区2郊县区2376名三～五年级小学生进行伤害相关危险行为问卷调查。结果2376名小学生骑车违规、步行违规、不安全游泳总体报告率分别为33.9%,13.0%,8.2%;受欺侮、打架、上下学不安全感总体报告率分别为51.6%,32.0%,6.1%;有孤独感、有学习压力、失眠、抑郁倾向总体报告率分别为24.1%,29.8%,9.6%,10.2%。男生危险行为报告率高于女生,郊区学生骑车违规行为报告率高于城区,城区学生孤独感、抑郁倾向行为报告率高于郊县区,单亲/重组/隔代家庭中儿童危险行为报告率较高。结论太原市小学生有关伤害危险行为报告率较高,伤害危险行为的发生受个体、家庭、社会的影响。     

Inhibitory Effect of Melatonin on the Growth of H22 Hepatocarcinoma Cells by Inducing Apoptosis

Whether melatonin not only inhibits the growth of H22 hepatocarcinoma cells but also induces apoptosis in vitro was assessed. The anti-proliferative effects of melatonin on tumor cells was observed by MTT assay and tumor cells growth curve assay. And the apoptosis of the cells was studied by acridine orange fluorescence assay and flow eytometry. The cell cycle of the tumor cells was also observed by flow eytometry. It was found that melatonin could significantly inhibit the growth of H22 hepatoeareinoma cells. Incubated with melatonin, ehromatin condensation of the tumor cells was observed by fluorescence microscopy. Compared with control, the percentage of apoptotic cells was increased, and the proportion of G0/S increased but that of G0/M decreased. It was suggested that melatonin could directly inhibit the growth of H22 hepatoearcinoma cells by inducing apoptosis and extending the length of cell cycle of the tumor cells.     

Melatonin protects N2a against ischemia/reperfusion injury through autophagy enhancement

Researches have shown that melatonin is neuroprotectant in ischemia/reperfusion-mediated injury.Although melatonin is known as an effective antioxidant,the mechanism of the protection cannot be explained merely by antioxidation.This study was devoted to explore other existing mechanisms by investigating whether melatonin protects ischemia/reperfusion-injured neurons through elevating autophagy,since autophagy has been frequently suggested to play a crucial role in neuron survival.To find it out,an ischemia/...     

一种帕金森病大鼠模型的建立及评价

目的探讨应用6-羟基多巴胺（6-OHDA）毁损大鼠黑质致密部制作偏侧帕金森病（PD）模型的方法和应用价值。方法采用立体定向微量注射6-OHDA于大鼠黑质致密部,观察经阿朴吗啡诱导后大鼠的行为及黑质多巴胺能神经元形态学变化。结果部分大鼠注射后即出现行动迟缓、少动、竖毛、躬身、尾部强直、肢体震颤、嗅探和易激惹等异常行为。术后4周时,共33只大鼠经阿朴吗啡诱导后在30min（P〈0．01）的平均旋转圈数〉7r／min,达到成功模型的标准,模型成功率为82．5％（33／40）。免疫组化观察发现模型组大鼠注射侧黑质区多巴胺能神经元较对侧和对照组注射侧区明显减少（P〈0．01）。结论利用6-OHDA毁损大鼠黑质致密部可以较快建立稳定的PD大鼠模型,方法简便实用,动物死亡率低,模型成功率高。     

蝙蝠葛酚性碱与褪黑素对缺血再灌注损伤神经元的作用比较

BACKGROUND： Recent studies have demonstrated that phenolic alkaloids from Menispermum dauricum （PAMD） can protect the heart and brain from ischemia/reperfusion injury, and promote neuron survival by inhibiting neuronal Bax and upregulating Bcl-2 expression following ischemia/reperfusion.
OBJECTIVE： To investigate the neuroprotective effects of PAMD versus exogenous melatonin against ischemia/reperfusion injury.
DESIGN, TIME AND SETTING： Observation and comparison experiments at a cellular level were performed at the Department of Biochemistry and Molecular Biology, Tongji Medical College of Huazhong University of Science and Technology between February 2007 and February 2008.
MATERIALS： PAMD （95% purity） was provided by Kunming Institute of Botany, Chinese Academy of Sciences; melatonin was provided by Sigma, USA.
METHODS： N2a mouse neuroblastoma cells were cultured in vitro deprived of glucose, serum and oxygen for 90 minutes, then cultured in normal medium containing different concentrations of PAMD （0.1, 1.0, 10 mg/L） or melatonin （1, 10, and 100 μmol/L）. Cells cultured in normal conditions served as a control.
MAIN OUTCOME MEASURES： The culture solution was collected to determine the content of ex- citatory neurotransmitters such as glutamic acid and aspartic acid; cell viability was detected by MTT methods; reactive oxygen species production was determined by fluorescence spectroscopy; mito- chondrial transmembrane potential （？Ψm） was detected by laser confocal scanning; cytochrome C was measured by western blotting; and caspase-3 activity was determined by visible spectropho- tometry.
RESULTS： Melatonin and PAMD both promoted oxygen-glucose-serum deprivation-mediated N2a cell survival （P 〈 0.01） and inhibited glutamic acid release （P 〈 0.01）, but melatonin did not inhibit aspartic acid production. The protective effects were the strongest using melatonin 100 μmol/L and PAMD 10 mg/L, so subsequent experiments were the performed at those doses. Although PAMD could no longer maintain mitochondrial transmembrane potential 6 hours after reperfusion, its in- hibitory effects on cytochrome C release from mitochondria and scavengers of reactive oxygen species were stronger than those of melatonin （P 〈 0.01）. However, its inhibitory effect on caspase-3 activity was weaker than that of melatonin： PAMD could inhibit caspase-3 activity 12 hours after reperfusion （P 〈 0.01）, but melatonin inhibited caspase-3 activity 28 hours after reperfusion （P 〈 0.01）.
CONCLUSION： The results show that melatonin and PAMD have neuroprotective effects, but that the mechanisms are varied. Melatonin can maintain mitochondrial transmembrane potential, but its inhibitory effects on cytochrome C release, caspase-3 activity, and reactive oxygen species scav-enging are different from those of PAMD.     

抑制beclin-1信号通路对缺血再灌注后神经母细胞瘤N2a细胞自噬的影响

目的观察抑制beclin-1信号通路对缺血再灌注后神经母细胞瘤N2a细胞自噬的影响。方法体外培养神经母细胞瘤系N2a细胞,脂质体转染beclin-1的miRNA干扰质粒,以缺氧、缺营养方式模拟缺血再灌注,甲基噻唑基四唑法检测各组N2a细胞活性,免疫印迹法测定各组N2a细胞beclin-1、微管相关蛋白1轻链3(LC3)、天冬氨酸特异性半胱氨酸蛋白酶3(Caspase3)的表达,电镜观察该细胞自噬活性。结果在缺血90min、再灌注24h干扰组较相应假干扰组细胞活性明显升高(P<0.05);干扰组beclin-1和Caspase3表达水平明显低于相应的假干扰组(P<0.05),但两组之间LC3表达无明显差异(P>0.05);而在缺血30min再灌注24h细胞活性,beclin-1、Caspase3和LC3的表达真假干扰组间无明显差异(P>0.05)。电镜下在正常组没有观察到细胞自噬现象;在缺血30min和90min再灌注24h,真假干扰组均观察到明显的细胞自噬现象,且两组间无明显差异。结论缺血90min,再灌注24h时,干扰beclin-1的表达虽不能明显改变N2a细胞自噬水平,却减少了凋亡,有利细胞存活。