磁性纳米颗粒对不同模式生物的毒性研究

磁性纳米颗粒在生物医学等领域应用广泛,而其毒性研究尚未深入,对生物的影响及作用机制仍未阐明。本文综述了磁性纳米颗粒近年来对于细胞、鼠、家兔和秀丽隐杆线虫的毒理学研究,为磁性纳米颗粒的应用提供参考。     

羧基化多壁碳纳米管对雌性小鼠卵泡发育的影响

碳纳米管(carbon nanotubes, CNTs)作为一种新形式的结晶碳,在工业及医药领域具有非常广阔的应用前景。本研究采用水溶性较好的羧基化多壁碳纳米管(MWCNTs-COOH)为研究对象,探索功能化多壁碳纳米管对小鼠卵巢发育的影响。将羧基化多壁碳纳米管溶解在含0.5% Tween-20的磷酸盐缓冲溶液(PBS)中,对实验小鼠按照2.5, 5, 10 mg·kg-1进行持续64 d的灌胃处理。处理结束后通过透射电子显微镜和HE染色观察卵巢组织的形态学变化。结果显示,碳纳米管确实进入了小鼠卵巢中。同时,随着MWCNTs-COOH暴露的增加,雌性小鼠卵泡数量显著减少,而雌性小鼠卵泡的形态结构并无明显影响。     

单壁碳纳米管对小鼠肝和肾氧化损伤的诱导

为了评价单壁碳纳米管(SWCNTs)对生物体的毒性效应,以昆明小鼠为受试动物,采用腹腔注射的染毒方法,研究了SWCNTs和标准碳黑(CB)对其肝和肾组织氧化损伤的诱导.实验结果表明:与对照组相比,SWCNTs和CB暴露显著的降低了小鼠肝和肾中还原性谷胱甘肽(GSH)的含量、抑制了超氧化物歧化酶(SOD)的活力、诱导了脂质过氧化终产物丙二醛(MDA)的产生、提高了DNA.蛋白质交联率(DNA.protein crosslinks,DPC),但在最高浓度(O.08 mg·d-1)暴露下,SWCNTs暴露组的影响程度要高于标准碳黑组.说明了SWCNTs暴露可以抑制小鼠肝和肾组织抗氧化系统,从而导致了器官的氧化损伤.并且这种氧化损伤的诱导部分是由于SWCNTs的特殊结构和金属元素的参与.     

高效氯氰菊酯对小鼠肝细胞的氧化损伤

为了探讨高效氯氰菊酯对生物体的氧化损伤,以昆明小鼠为受试体,高效氯氰菊酯按10、和40mg·kg20-13个剂量水平,灌胃染毒小鼠7d,并以肝匀浆测定活性氧自由基(ROS)、还原型谷胱甘肽(GSH)、丙二醛(MDA)含量,以肝细胞测定DNA-蛋白质交联(DPC)系数.实验结果表明,随着高效氯氰菊酯染毒剂量的升高,ROS和MDA含量及DPC系数逐渐上升,GSH含量逐渐降低,各指标呈一定的剂量-效应关系.染毒剂量≥20mg·kg-1时,处理组的ROS含量和DPC系数与对照组有显著差异(p<0.05);染毒剂量≥40mg·kg-1时,GSH和MDA含量与对照组有显著差异(p<0.05),DPC系数有极显著差异(p<0.01).说明较高剂量的高效氯氰菊酯可造成小鼠肝脏的氧化损伤和DNA-蛋白质交联作用增强.     

Impact of astaxanthin-enriched algal powder of <Emphasis Type="Italic">Haematococcus pluvialis</Emphasis> 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.