Differential expression of NADH-cytochrome b5 reductase in the rds mouse

AIM:To identify the genes that were differentially expressed in the retina of rds mouse during the development of retinitis pigmentosa.METHODS:mRNA differential display method was used to compare and analyze mRNA samples prepared from the retina of rds mouse and normal mouse on postnatal day 25(P25). Differentially expressed fragments were cloned, sequenced and compared with GenBank database by BLASTN. Expression difference was further investigated by gene-specific primer RT-PCR.RESULTS:Obvious difference in gene expression occurred between rds mouse and normal mouse. One fragment, clone No.5, shared 91% homology with rat NADH-cytochrome b5 reductase (b5R) cDNA. Thus, it was identified as mouse b5R cDNA. Gene-specific RT-PCR confirmed that b5R mRNA level was increased in the retina of rds mouse compared with normal mouse on postnatal day 12, 25 and 37, respectively.CONCLUSION:Certain oxidative factors may up-regulate the expression of b5R resulting in large consumption of NADH and production of NAD⁺, through which apoptotic retinal cell death was enhanced.     

The tumor-seeking specificity of [125I]-(A14)-insulin in human hepatoma bearing nude mice

AIM: To observe tumor-seeking specificity of [¹²⁵I]-(A14)-insulin in human hepatoma bearing nude mice. METHODS: The in vivo tissue distribution and inhibition studies of [¹²⁵I]-(A14)-insulin in human hepatoma bearing nude mice were performed. RESULTS: In the tissue distribution study, a significant accumulation of [¹²⁵I]-(A14)-insulin was observed in the tumor site of nude mice. The tumor/blood and tumor/muscle radioactive ratio gradually increased with lengthening time following injection of [¹²⁵I]-(A14)-insulin. The inhibition ratio in the tumor tissue of nude mice in the inhibition study was 35.0%. CONCLUSION: There is a specific uptake of [¹²⁵I]-(A14)-insulin through receptor-mediated process in the hepatoma tissue of nude mice.     

硒对镉诱导的小鼠肝组织脂质过氧化作用的影响

通过单独和联合在腹腔内注射ＣｄＣｌ２（３ｍｇ／ｋｇ体重）和Ｎａ２ＳｅＯ４（２ｍｇ／ｋｇ体重）的方法硒对镉诱导的小鼠肝脂质过氧的保护效应。结果表明，单独镉处理小鼠在整个实验期间肝丙二醛含量明显升 高，谷胱甘肽过氧化物酶、超氧化物歧化酶和过氧化氢酶活性显著下降；硒镉联合处理未引起ＬＰＯ的明显增强，抗氧化酶特别是ＧＳＨ－Ｐｘ在不同程度上受到有效地保护。因而认为，镉诱导的ＬＰＯ与抗氧化酶的抑制密切相关。硒     

Effects of carbon monoxide on hypoxia inducible factor-1 expression in hypoxia preconditioned mice

AIM:To study the effect of carbon monoxide (CO) on hypoxia inducible factor-1α(HIF-1α) expression and on hypoxic tolerance duration in hypoxia preconditioned mice. METHODS:Mice were injected with normal saline (NS) or hemin intraperitoneally. Western blot was used to detect HIF-1α in hippocampus. The tolerant duration of each hypoxic run was recorded. RESULTS:After 1 and 2 runs of hypoxia exposure, there were no significant differences in HIF-1α expression and hypoxic tolerance duration between N and hemin injection groups. After 3 and 4 runs of hypoxia exposure, the content of HIF-1α was lower and hypoxic tolerance duration was shorter (P＜0.05) in hemin injection groups than that in NS injection groups. CONCLUSION:CO could decrease the expression of HIF-1α, and decrease hypoxic tolerance duration in hypoxia preconditioned mice. The mechanism may be that CO binds to hemoprotein and inhibits hemoprotein oxygen sensor.     

牛蒡提取物抗疲劳作用的研究

将雄性BALB/C小鼠按体重随机分为4组:空白对照组和2.0、4.0、6.0 g/kg 3个牛蒡提取物剂量组。在给予受试物20 d后测定各组小鼠负重游泳的持续时间,10 min无负重游泳的血乳酸水平(静息值、即刻值、游泳后20 min值)及肝糖原含量的变化。结果2.0、4.0、6.0 g/kg剂量的牛蒡提取物能提高肝糖元的储备(p<0.05,p<0.01);4.0、6.0g/kg剂量组游泳时间长于空白对照组(p<0.05);4.0、6.0g/kg剂量组血乳酸降低比值高于对照组(p<0.05,p<0.01)。结论:牛蒡提取物具有明显抗疲劳作用。     

钙调蛋白(CaM)对附植前小鼠胚胎热休克蛋白70(HSP70)表达的影响

体外培养的奶牛,绵羊和小鼠的附植前胚胎在热应激条件下能够合成热休克蛋白70以增强胚胎的耐热性保护其不受热损伤.而钙调蛋白(CaM)是细胞内最重要的Ca2+受体蛋白并参与细胞活动中重要基因的转录活动.本实验旨在研究CaM参与小鼠(Mus musculus)胚胎热应激诱导型热休克蛋白70(HSP70)的表达,且明确CaM参与HSP70表达的具体途径.将发育至早期囊胚的胚胎分成空白对照(37℃)组、W7处理非热应激(37℃+W7)组、热应激(39℃)组和W7处理热应激(39℃+W7)组.提取总RNA并分别检测HSP70、CaM和热休克转录因子1(HSFl) mRNA表达;提取胞浆蛋白用Western blot技术检测HSP70、CaM和HSF1表达;用免疫共沉淀法检测HSP70-CaM和HSP70-HSF1复合物.结果发现,W7能显著抑制39℃热应激1h小鼠胚胎HSP70 mRNA和蛋白的表达(P＜0.05); W7对其他各组胚胎HSF1mRNA表达的影响不显著(P＞0.05),但能显著降低39℃热应激1h小鼠胚胎HSF1蛋白表达(P＜0.05); 39℃热应激时,胚胎HSP70-CaM复合物增多,HSP70-HSF1复合物减少.本研究表明,小鼠胚胎受热应激时,CaM通过与HSP70竞争性结合,解离出HSF1,从而使HSP70大量表达.本研究揭示了CaM参与小鼠胚胎热激反应中HSP70表达的一种途径.可为研究胚胎耐热性以及热激信号转导提供基础资料.     

Differentiation of neurons from mouse induced pluripotent stem cells in vitro

AIM: To study the induction method of mouse induced pluripotent stem cells (iPSCs) that differentiate into neurons in vitro. METHODS: Mouse iPSCs were cultured in non-adherent culture dishes for 2 d to form embryoid bodies (EBs). The EBs were cultured for consecutive 2 d in the presence of retinoic acid (RA), and then were plated in the serum-free medium for adherent culture. Seven days later, Pasteur pipette was used to detach the differentiated cells around adherent EBs into “fragment” cell colonies with the help of dissecting microscopes, and these “fragments” were transferred to culture dishes with neural stem cell medium. Another 7 days later, the cells were plated onto the culture dishes using differentiation medium containing fetal bovine serum (FBS) and RA. The morphological changes of the cells were observed under inverted microscope. The iPSCs markers Oct4, Sox2 and SSEA1, the neural stem cell (NSC) marker nestin, the neuronal marker microtubule-associated protein 2 (MAP-2), the astrocyte marker glial fibrillary acidic protein (GFAP) and oligodendrocyte marker myelin basic protein (MBP) were detected by immunofluorescence method. The mRNA expression of GFAP, nestin, β3-tubulin, MAP-2 and MBP was detected by RT-RCR. MAP-2 gene sequence was identified. The proportions of NSCs differentiated from iPSCs and neurons from NSCs were detected by flow cytometry. RESULTS: Mouse iPSCs strongly expressed Oct4, Sox2 and SSEA1, and formed spherical EBs by suspended culture. The EBs were induced by RA and serum-free medium in adherent culture for 2 d, and rosette structure was observed under the microscope. “Fragments” separated by Pasteur pipette from the rosette structure formed neurosphere-like colonies. After the colonies were cultured in adherent condition for 5 d to 7 d in the presence of RA and FBS, the typical neurite was observed under the microscope. The neurospheres expressed nestin and their differentiated derivatives expressed MAP-2, GFAP and MBP, respectively. RT-PCR analysis and gene sequencing showed that the neurons were induced successfully. The results of flow cytometry demonstrated that 63.93%±1.47% of iPSCs differentiated into NSCs and 21.4%±1.70% of NSCs differentiated into neurons. CONCLUSION: Mouse iPSCs proliferate stably and differentiate into neurons in vitro, which provide a reliable source for the treatment of spinal cord injury.     

茶树油提取物粉对小鼠免疫功能的影响

研究茶树油提取物粉对小鼠免疫功能的影响,为茶树油产品的研发及作为畜禽养殖添加剂的应用积累资料。茶树油提取物粉对小鼠的经口急性毒性LD_(50)﹥5000 mg/kg b.w.。茶树油提取物粉分别以1250、250、50 mg/kg b.w.灌胃给予连续10 d,分别进行腹腔巨噬细胞吞噬活性和脾淋巴细胞增殖试验,测定免疫器官指数、血清溶血素水平及外周血CD3~+、CD4~+、CD8~+T淋巴细胞亚群水平。结果表明茶树油提取物粉高、中、低剂量组能极显著增加小鼠脾脏指数(P0.01),中剂量能显著增加肝脏指数和胸腺指数(P0.05)。中、高剂量能显著提高腹腔巨噬细胞吞噬活性和血清溶血素水平(P0.05)。三个剂量组均能显著提高小鼠脾淋巴细胞增殖的刺激指数(P0.05)。中剂量组能显著增加小鼠CD4+/CD8+比值(P0.05)。因此,茶树油提取物粉在一定程度上能够提高小鼠细胞免疫和体液免疫,具有增强小鼠免疫功能的作用。     

长白山人参对小鼠的急性毒性实验

目的 观察人参水煎液对小鼠灌胃给药后急性毒性反应,评价其安全性,为中医临床应用提供参考依据.方法:以人参水煎液最大浓度、最大体积对小鼠进行一次灌胃给药,观察7d内小鼠的毒性反应以及死亡情况.结果 人参水煎液2g/ml,0.4ml/10g进行灌胃给药,与成人日用人参量3～9g相比,相当于成人临床用量的266.67～800倍,却未见药物引起的毒性反应和死亡情况.结论 人参水煎液具有较好的安全性.     

赣南脐橙皮中黄酮的提取及抗疲劳作用研究

[目的]对赣南脐橙皮抗小鼠运动性疲劳作用效果进行研究。[方法]将橙皮黄酮分2个剂量组即1.0、2.0 g/kg给试验组小鼠灌胃,对照组为生理盐水。30 d后小鼠游泳造成运动性疲劳,测定小鼠力竭游泳时间、血清尿素氮（BUN）、肝组织丙二醛（MDA）及超氧化物歧化酶（SOD）指标。[结果]与运动对照组相比,小鼠负重力竭游泳时间显著延长,BUN、MDA指标明显下降,SOD活性显著升高。[结论]橙皮黄酮能显著提高小鼠的抗疲劳能力。