甲基叔丁基醚对大鼠肝组织基因表达的影响

Effects of Methyl Tertiary Butyl Ether on Liver Tissue Gene Expression in Rats

目的甲基叔丁基醚（ＭＴＢＥ）是一种新型的汽油添加剂，动物试验显示其具有一定的致癌性。为了解其动物致癌性的可能机制，我们检测了经ＭＴＢＥ亚慢性染毒的大鼠肝组织中原癌基因ｃｍｙｃ基因和功能基因谷胱甘肽Ｓ转移酶Ｐ（ＧＳＴＰ）基因的表达情况。方法４０只雄性ＳＤ大鼠，体重１８０～２００ｇ，随机分为４组。将ＭＴＢＥ溶于适量豆油中，灌胃染毒，染毒剂量分别为２００ｍｇ／ｋｇ，６００ｍｇ／ｋｇ，１０００ｍｇ／ｋｇ和对照组。每天１次，每周５天，共１３周。动物肝组织于液氮速冻后，一步法提取总ＲＮＡ。随机引物法地高辛标记ｃｍｙｃ和ＧＳＴＰ探针，与ＲＮＡ进行点杂交，图像分析仪分析结果。结果大鼠肝组织中ｃｍｙｃ基因表达水平明显增高，ＧＳＴＰ基因表达未见增强。结论ＭＴＢＥ可明显诱导ｃｍｙｃ基因的高表达，提示其具有促进细胞增殖的作用，这是其动物致癌性的可能机制之一。

Objective Methyl tertiary butyl ether (MTBE) is a new gasoline additive, with certain carcinogenecity in animal experiments. To study its possible mechanism of carcinogenesis in animals,expression of protooncogene c myc and functional gene glutathione S transferase P (GST P) in the liver tissues of rats chronically exposed to MTBE was deteited. Methods Forty male SD rats with body weights of 180 200 grams were randomly divided into four groups and gavaged with MTBE dissolved in soybean oil with doses of 1 000, 600, 200 and 0 mg/kg, respectively, once daily and five days a week for 13 weeks. Liver tissues of the animals were frozen quickly in liquid nitrogen and their total RNA extracted with one step method. The probes of c myc and GST P were labeled with digoxin by random primer method, and dots hybridization with RNA was used. Results Levels of expression of c myc gene in the liver tissues of rats increased significantly, but not for those of GST P. Conclusion MTBE can induce the higher expression of c myc gene, which suggests it can promote cell proliferation one of possible mechanisms of carcinogenesis in animals.