低剂量X射线辐射对BALB/C小鼠免疫系统的影响

为评估低剂量辐射对健康机体产生的生物学风险,检测了低剂量X射线照射对BALB/C小鼠免疫系统的影响。采用X射线全身照射,剂量分别为0、0.39、0.55和1Gy,剂量率为0.2Gy/min,照射24h后取血及器官,用流式细胞仪检测免疫细胞周期和凋亡的变化,用重量法得到胸腺和脾脏指数。发现照射后小鼠的外周血淋巴细胞、胸腺细胞和脾脏淋巴细胞的周期被阻滞在G0—G1期;外周血淋巴细胞和胸腺细胞的凋亡比例随剂量的增大而增大,但是脾脏淋巴细胞的凋亡随着剂量的增大而减小;胸腺和脾脏指数随着剂量的增大而减小。故低剂量X射线全身照射可引起试验动物的免疫细胞周期和凋亡比例发生变化,对其造成一定的损伤;对小鼠免疫系统的影响因器官而异。本实验可为辐射防护提供实验依据。

Impact of astaxanthin-enriched algal powder of Haematococcus pluvialis on memory improvement in BALB/c mice

The impact of astaxanthin-enriched algal powder on auxiliary memory improvement was assessed in BALB/c mice pre-supplemented with different dosages of cracked green algal (Haematococcus pluvialis) powder daily for 30 days. The supplemented mice were first tested over 8 days to find a hidden platform by swimming in a Morris water maze. Then, for 5 days, the mice were used to search for a visible platform in a Morris water maze. After that, the mice practised finding a safe place-an insulated platform in a chamber-for 2 days. During these animal experimental periods, similar algal meals containing astaxanthin at 0, 0.26, 1.3 and 6.4 mg/kg body weight were continuously fed to each group of tested mice. Profiles of latency, distance, speed and the direction angle to the platforms as well as the diving frequency in each group were measured and analyzed. The process of mice jumping up onto the insulated platform and diving down to the copper-shuttered bottom with a 36 V electrical charge were also monitored by automatic video recording. The results of the Morris maze experiment showed that middle dosage of H. pluvialis meals (1.3 mg astaxanthin/kg body weight) significantly shortened the latency and distance required for mice to find a hidden platform. However, there was no obvious change in swim velocity in any of the supplemented groups. In contrast, the visible platform test showed a significant increase in latency and swim distance, and a significant decrease in swim speed for all groups of mice orally supplemented with H. pluvialis powder compared to the placebo group (P < 0.05 or P < 0.01). Mice supplemented with the algal meal hesitantly turned around the original hidden platform, in contract to mice supplemented with placebo, who easily forgot the original location and accepted the visible platform as a new safe place. These results illustrate that astaxanthin-enriched H. pluvialis powder has the auxiliary property of memory improvement. The results from the platform diving test showed that the low and middle dosage of H. pluvialis powder, rather that the high dosage, increased the latency and reduced the frequency of diving from the safe insulated platform to the electrically stimulated copper shutter, especially in the low treatment group (P < 0.05). These results indicate that H. pluvialis powder is associated with dose-dependent memory improvement and that a low dosage of algal powder (<= middle treatment group) is really good for improving the memory.

80MeV/u ~(12)C~(6+)离子辐照小鼠头部对骨髓细胞周期分布的影响

研究重离子辐照小鼠头部对骨髓细胞周期分布的影响,为重离子放射治疗癌症和太空防护提供基础数据。80MeV/u能量的12C6+离子对BALB/c小鼠头部给以0、0.5、1、2、4、10Gy的照射,用流式细胞仪测骨髓细胞周期分布。随着重离子辐照剂量的增加,G1/G0期细胞出现明显阻滞(P<0.05),而G2/M期细胞出现显著减少(P<0.05)。说明重离子辐照小鼠头部对小鼠骨髓细胞周期分布有明显影响,也同时表明电离辐射对骨髓细胞周期分布的影响也有一种间接作用。

80MeV/u~(12)C~(6+)离子辐照小鼠头部对脾脏细胞周期分布的影响

研究重离子辐照小鼠头部对脾脏细胞周期分布的影响,为重离子放射治疗癌症和太空防护提供基础数据。80MeV/u能量的12C6+对BALB/c小鼠头部给以0、0.5、1、2、4、10Gy的照射,用流式细胞仪测脾脏细胞周期分布。重离子辐照后36h,小鼠脾脏细胞S期细胞随着辐照剂量的增加显著减少(p<0.05);0.5Gy组、4Gy组和10Gy组出现G1/G0期阻滞明显阻滞(p<0.05),1Gy组和2Gy组无显著变化(p﹥0.05);0.5Gy组G2/M期细胞显著减少(p<0.01),其它剂量组明显阻滞(p<0.05)。重离子辐照小鼠头部对小鼠脾脏细胞周期分布有明显影响。

眼镜王蛇毒单克隆抗体的制备

目的:应用眼镜王蛇毒基因疫苗,免疫BALB/c小鼠,制备单克隆抗体(mAb).方法:应用眼镜王蛇Oh-3基因真核表达质粒pIRES-Oh3,佐以脂质体制成基因疫苗,免疫BALB/c小鼠,取其脾细胞与同源Sp2/0骨髓瘤细胞进行融合,经间接ELISA筛选,有限稀释法克隆,制备mAb.结果:获得了2株分泌抗眼镜王蛇毒mAb的杂交瘤细胞株(F5、 F11),细胞培养上清液的抗体效价分别为3.2×10-1、 6.4×10-1,腹水抗体效价分别为1.28×10-4、 2.56×10-4.结论:成功地制备了2株眼镜王蛇毒mAb.

以人精子抗原消化道免疫后的体液免疫反应

在Balb/c、C57和昆明鼠的消化道不同部位以人精子抗原免疫后, 取其脾、 肠系膜淋巴结、Peyer氏淋巴小结及子宫或附睾中的淋巴细胞进行培养。Balb/c 和昆明鼠抗精子免疫反应较强, 且雌性强于雄性。免疫部位以小肠及Peyer氏淋 巴小结内注射的免疫效果较好, 不仅可引起消化道局部免疫反应, 而且子宫、附 睾等生殖道组织也有淋巴细胞分泌抗精子抗体。表3参18

SECRETORY MONOCLONAL IGA ANTIBODY TO HUMAN SPERM PRODUCED BY GASTROINTESTINAL IMMUNIZATION INHIBITS HUMAN SPERM ACTIVITY AND MOUSE INVITRO FERTILIZATION

BALB/c mice were immunized intragastrically with human sperm. Cells from the Peyer's patches and spleens of the immunized mice were for the preparation of hybridomas secreting antisperm monoclonal IgA (mcIgA). The specific ratio of IgA-secreting cells in Peyer's patches was much higher than that in spleen. The binding site on human sperm of 9 of 19 mcIgA was in the post-acrosomal region using an immunofluorescent assay. Two of eight selected mcIgA caused strong human sperm agglutination and three of them produced significant inhibition of mouse in vitro fertilization. No mcIgA tested caused obvious human sperm immobilization or inhibited mouse in vivo fertilization. In vitro assembly of selected mcIgA in ascites with mouse secretory component (SC) caused no significant changes in effects on sperm function and in vitro fertilization. By use of Western blotting, dimer or higher polymers were demonstrated in all selected mcIgAs and corresponding protein antigens in 6 of 8 selected mcIgAs. These results suggest that human sperm function may be inhibited and fertilization rate reduced by specific secretory IgA to human sperm and that secretory immunity to protein antigens of human sperm could be induced by intragastrointestinal immunization.

Transport of anti-sperm monoclonal IGA and IGC into murine male and female genital tracts from blood - Effect of sex hormones

Ab levels in the genital tract may be important in fertility and in preventing sexually transmitted diseases, In this study, I-125-labeled polymer or monomer mAb IgA (C4pIgA or C4mIgA) and IgC2b (C4IgC) to murine lactate dehydrogenase C4 and a polymer mAb IgA (npIgA) not cross-reacting with mouse sperm were intravenously injected into BALB/c mice, and the relative distribution of these Abs was determined. Polymer IgA was transported much more efficiently into the genital tract, trachea, and duodenum of both sexes than C4IgG and C4 mIgA (p < 0.01), The transport of polymer IgA (C4pIgA and npIgA) into the male genital tract greatly increased following orchiectomy (p < 0.01); this change was not affected by testosterone, suggesting that the unknown regulatory factor(s) from the testis may suppress polymer IgA transport, However, the transport of polymer IgA into female genital tissues was significantly decreased by ovariectomy (p < 0.01); this decline can be rectified by P-estradiol but not progesterone treatment, suggesting that estradiol may stimulate polymer IgA transport, Furthermore, the transport of C4IgG into tissues of the Fallopian tubes and the uterus was significantly decreased by treatment with progesterone (p < 0.01). Together, these findings indicate that serum polymer IgA can be transported selectively into the genital tracts of both sexes, that this transport is strongly under the control of gonads, and that transport of Ige into the Fallopian tubes and uterus is downregulated by progesterone.

Gene mapping of a new coat mutation in mouse

Gene mapping of a mouse coat mutation has been investigated. First, 100 10-bp random primers were used to amplify DNA, but the mutation could not be located by this method because there were no correlation between the amplified products and coat phenotypes. Second, by using Idh1, Car2, Mup1, Pgb1, Hbb, Es10, Es1, Mod1, Gdc1, Ce2, Es3 as genetic markers, linkage test crosses (two-point test) consisting of intercrossing uncovered BALB/c mice (homozygotes) to CBA/N and C57BL/6 mice with normal hair and backcrossing the heterozygotes of the F1 to the uncovered BALB/c mice were made. It was soon evident that the mutation was linked to Es3 on chromosome 11. Furthermore, three-point test was made by using Es3 and D11Mit8 (a microsatellite DNA) as genetic markers. The result showed that the mutation was linked to Es3 with the percentage recombination of (7.89 +/- 2.19)%, and linked to D11Mit8 with the percentage recombination of (26.38 +/- 3.57)%. The percentage recombination between Es3 and D11Mit8 was (32.90 +/- 3.81)%. The mutation was named Uncovered, with the symbol Uncv. According to the recombinations, the loci order was D11Mit8-26.30 +/- 3.57- Uncv-7.89 +/- 2.19-Es3. From the location on the chromosome, it was concluded that the mutation was a new mutation which affected the skin and hair structure of mouse. The Uncv has entered MGD (Mouse Genome Database).

鱼肉结合态MCLR的亚慢性毒性研究

为了揭示含有微囊藻毒素水产品的食用安全性,以雄性BALB/C小鼠为模式生物,通过为期13周的灌胃染毒实验,研究了鱼肉结合态MCLR对小鼠的亚慢性毒性作用,并与水溶态MCLR的毒性进行了对比.结果表明,68.75μg/kg(以单位体重计)剂量水溶态MCLR可引起小鼠肝脏显著系数增加(p<0.05),ALT、AST活性增强(p<0.01),引起肝细胞出现有空泡状病变;而肾脏酶学指标BUN、Cr及肾脏组织病理学观察均未发现明显异常;与之相比,同剂量鱼肉结合态MCLR对小鼠各项指标的影响并不明显,仅在实验第1周出

微囊藻毒素LR对小鼠的急性毒性研究

目的了解微囊藻毒素对小鼠的急性损伤作用。方法以BALB/C小鼠为材料,腹腔注射22μg/kg·b.w.和43μg/kg·b.w.剂量的微囊藻毒素LR,测定脏器系数和一系列生化指标。结果肾脏指数与肝脏指数明显增加,表明两种器官都受到损伤;血清中天冬氨酸转氨和丙氨酸转氨酶活力上升,尿素含量下降预示着肝脏损伤,尿酸含量上升则预示肾脏损伤的发生。结论肾脏也可能是易受微囊藻毒素损伤的器官。

甲状腺素脱碘酶的人工模拟研究

甲状腺激素，特别是3，3'，5一三碘甲状腺素（T_3）对机体新陈代谢与能量的内稳定、生长发育、其它激素分泌等发挥着重要调节作用。甲状腺素脱碘酶是九十年代后才发现的能够催化甲状腺激素不同降解反应的一簇含硒酶，对维持甲状腺激素在体内的动态平衡和生物活性起关键作用。它们的缺乏将导致机体产生多种与甲状腺激素有关的严重疾病。由于脱碘酶稳定性差，体内含量极微且基因表达困难等，因此，开展脱碘酶的人工模拟研究具有重要意义。以天然脱碘酶的初步催化机制和疏水腔修饰法的半抗原设计思想为依据，设计合成了三种疏水性不同的甲状腺素衍生物半抗原：o-methyl-T_4，o-benzyl-T_4和o-p-nitro-benzyl-T_4，并对其结构进行了表征。半抗原与载体蛋白偶联制备出全抗原，经免疫Balb/C小鼠、细胞融合、多轮克隆化与筛选，获得一株分泌抗-T_4的单抗细胞株4C5和一株分泌抗-o-methyl-T_4的单抗细胞株688。经腹水制备和分离纯化，获得单克隆抗体4C5和6E8。通过化学组装将催化基团Sec引入到抗体的抗原结合部位，制备出两种分别对半抗原T_4和o-methyl-T_4特异的含硒抗体酶Se-4C5和Se-6E8，其最大酶活力分别为270和480 U/mg protein,为含天然酶的鼠肝匀浆液活力(36 Ulmg protein)的7.5及13.3倍，是国内外首次报道的具有脱碘酶活性的含硒抗体酶。同时对它们的理化性质、酶促反应、动力学性质以及Fab片段的活性等方面进行了系统的研究，用化学修饰法鉴定了催化部位的一些关键氨基酸。指出抗体酶催化的反应与工型脱碘酶相似，属乒乓机制，且PTU抑制作用也相一致，因此确认为I型脱碘酶模拟物，并提出了较详细的脱碘酶催化机制和过渡态的形成过程，这将对天然脱碘酶催化机理的完善和药用价值的模拟酶研究等具有重要意义。

重组人内皮抑素的基因表达与表征

内皮抑素具有抑制内皮细胞增殖和抗肿瘤新生血管生成活性，在小鼠实验中对多种肿瘤取得了有效的结果，有望成为一种新型抗肿瘤药物。本论文从基因的获取到在大肠杆菌中的高效表达，系统地研究了重组内皮抑素的全过程，并对其体内、体外的生物学活性及多种光谱学性质进行了深入的研究。采用Trizol试剂改进法从人胚肝组织中制备细胞mR NA，通过RT-PCR方法获得人内皮抑素基因。应用基因工程技术构建了亚克隆载体和表达载体，在大肠杆菌BL21（DE3）中以包涵体方式表达出N-末端带有6XHisTag标签的融合蛋白，表达量最多达到菌体总蛋白的42％。建立了包涵体蛋白的复性和纯化方法，得到具有较高纯度的重组内皮抑素蛋白。首次用质谱法证实从大肠杆菌的包涵体中获得的重组蛋白，因宿主菌中水解甲硫氨酸的酶不能对所有包涵体蛋白起作用，而在目的蛋白中会棍有N-末端具有甲硫氨酸的产物。对内皮抑素基因做定点突变，首次将内皮抑素蛋白的N-末端锌离子结合位点的的His2、His4突变成Leu2、Va14，构建了点突变的亚克隆载体，为以后研究其作用机理提供了条件。重组内皮抑素能够抑制鸡胚尿囊膜血管生成和人脐静脉内皮细胞ECV-304的增殖，在小鼠体内实验中对黑色素瘤产生良好的抑瘤效果（P＜0.01）。通过细胞周期分析，首次发现重组内皮抑素在G2期抑制 ECV-304细胞的增殖。电镜观察发现受内皮抑素作用的ECV-304细胞，产生了凋亡小体并出现多种细胞凋亡特征。同时，首次发现内皮抑素能使Balb／c 3T3细胞产生凋亡。计算机结构模拟结果表明重组内皮抑素蛋白与天然蛋白具有相似的空间结构。研究了内皮抑素与锌离子、肝素、稀土离子作用后蛋白质的光谱学性质和二级结构的变化，首次发现偏酸性pH对肝素与内皮抑素的结合作用有特殊影响，为研究内皮抑素特异抑制肿瘤组织新生血管的生成提供了实验依据。从人胚肝组织出发初步完成了人硒蛋白P亚克隆载体的构建。

抗LDH-C4的IgA单克隆抗体在生殖道局部的分布

为了弄清生殖道内抗体，特别是IgA抗体的准确来源和它的调控因子，同时也为了弄清生殖的局部免疫与典型的粘腊免疫之间的关系，以同位素标记的针对精子特有抗原乳酸脱氢酶C4(LDH-C4)的多聚IgA单抗及其单体，与小鼠精子发生反应的IgA单抗，以及LDH-C4特异的IgG抗体，尾静脉注射给雌雄Balb/c小鼠，4小时后测定小鼠的生殖道及其分汾物，肠道、呼吸道及其分泌物，各相关淋巴组织以及其它器官内这些抗体的分布。还研究了特异抗原刺激、性激素等对这些抗体分布状况的影响。