壳聚糖纳米混悬剂抗突变生物学效应:原核细胞基因突变试验

Anti-mutation effects of chitosam nano-suspension:Gene mutation test of prokaryocytes

背景:抗突变剂能有效阻止化学致癌物对遗传物质的损害,因此,积极寻找具有抗突变作用的生物资源具有重要的意义。目的:系统评价壳聚糖纳米混悬剂对多种强阳性诱变剂的抗突变效应。设计、时间及地点:体外对照观察试验,于2007-03/2008-03在浙江省医学科学院生物工程研究所完成。材料:自制壳聚糖纳米混悬剂(平均粒径25.3nm,占总粒子数99.1%),8种诱变剂均购自美国Sigma公司。方法:用鼠伤寒沙门氏菌回复突变试验(Ames试验),将壳聚糖纳米混悬剂设定为高、中、低(2500,1250,625μg/皿)3个剂量组,分别对NaN3、MMC、9-AA、2,7-AF、NQNO、Dexon、CP、2-AF等8种常用诱变剂进行抗突变作用观察。主要观察指标:根据平均回变菌落数计算抑制率,用抑制率判断其抗突变作用程度。结果:高、中剂量组壳聚糖纳米混悬剂对NaN3、MMC、9-AA、2,7-AF、NQNO、CP和2-AF分别呈中度抑制和弱抑制,低剂量组无抑制作用。壳聚糖纳米混悬剂对诱变剂Dexon显示出较强的抗突变效应,3个剂量组对Dexon诱发的回变菌落数均显著下降(P<0.01)。随着壳聚糖纳米混悬剂浓度的增加,对不同致突变剂产生的诱发回变菌落数明显下降,抑制率上升,呈现量效关系。结论:壳聚糖纳米混悬剂对多种诱变剂具有不同程度抗突变效应,并呈现量效关系。

BACKGROUND： Anti-mutation reagent can effectively inhibit damage of chemical carcinogens to genetic material. Thus it is significant to search biotic resources with anti-mutative effects. OBJECTIVE： To evaluate anti-mutative effects of chitosam nano-suspension on various strong positive mutagens. DESIGN, TIME AND SETTING： In vitro controlled observation was performed at the Institute of Bioengineering, Zhejiang Academy of Medical Sciences between March 2007 and March 2008. MATERIALS： Chitosam nano-suspension was prepared by our laboratory, 25.3 mm diameter, accounted for 99.1% of total particle number; eight mutagens were purchased from Sigma, USA. METHODS： Using Ames test, eight mutagens including aN3, MMC, 9-AA, 2,7-AF, NQNO, Dexon, CP, and 2-AF were exposed to chitosam nano-suspension at dose of 2 500, 1 250, and 625 μg per vessel. MAIN OUTCOME MEASURES： Inhibition ratio was calculated according to mean colony number of back mutation to identify anti-mutation effect of chitosam nano-suspension. RESULTS： High and middle dose of chitosam nano-suspension showed moderate and weak inhibition effects on NAN3, MMC, 9-AA, 2,7-AF, NQNO, CP and 2-AF. Low dose of chitosam nano-suspension had no inhibition. Chitosam nano-suspension exhibited strong anti-mutation effect on Dexon, but the colony number of back mutation was decreased with dose （P 〈 0.01）. The colony number of back mutation of mutagens significantly decreased with increasing dose, but the inhibition ratio increased in a dose-effect relationship. CONCLUSION： Chitosam nano-suspension exhibits different anti-mutation effects on various mutagens in a dose-effect relationship.