转溶菌酶基因水稻稻米毒理及致畸作用试验

Toxicology and teratogenicity tests of transgenic rice with lysozyme gene from T4 phage

通过小鼠急性毒性试验、大鼠长期毒性试验、小鼠微核试验和精子致畸试验对转溶菌酶基因水稻稻米的毒性及致畸作用进行了初步的评价。转基因大米淀粉灌胃小鼠，剂量相当于成人每日食用2250g，连续7d观察，动物全部存活，表现正常，未见动物出现中毒反应，小鼠灌胃转基因大米的最大耐受量MTD≥37．5g／kg。转基因大米粉分别以15g／kg／d和7．5g／kg／d2个剂量，相当于成人日食用量900g和450g，连续94d灌胃大鼠，灌胃期间动物的行为活动、外观体征、饮食、粪便、体重均无异常。5项血液学检查和13项生化指标检测及处死1／2的动物尸体解剖观察、脏器系数及脏器病理学检查，结果均属正常，与空白对照无显著差异；剩余1／2的动物留存观察2周，各项观察指标、血液、生化及病理检测也无异常。转基因大米粉以15g／kg和7．5g／kg2个剂量分别灌胃小鼠，未发现对小鼠骨髓细胞微核和精子畸形发生率有不良影响。本试验结果提示携带溶菌酶基因、NPT-Ⅱ标记基因等外源DNA的转基因大米无明显的毒性和致畸作用。

Safety evaluation of the transgenic rice flour possessing the lysozyme gene from T4 phage and foreign DNA sequences including NPT Ⅱ gene was conducted by feeding and teratogenicity tests with rats or mice. All mice administered the solution containing transgenic rice flour by enema at a heavy dose of 37.5 g/kg were alive and no significant toxic effect was observed in growth, body weight gain. Ninety-four-day mice feeding test showed no significant differences in physical sign, growth, body weight gain, 5 hemogram indexes and 13 biochemical indexes of blood, organ relative weights and pathologic anatomy between rats administered the solution containing transgenic rice flour at two doses of 15 g/kg and 7.5 g/kg and equate volume of 0.9% physiological saline as control by enema. It was found that the lysozyme transgenic products showed no genotoxicity and teratogenicity effect in vivo by the micronucleus and sperm aberration tests at two doses of 15 g/kg and 7.5 g/kg. These results indicate that the lysozyme transgenic rice is as safe as existing commercial rice.