不同诱导方式制备的大鼠肝匀浆代谢酶活性及冻储方式的比较

目的：研究7种不同诱导方式制备的大鼠肝匀浆的代谢酶活性，并探讨用低温液体法保存肝匀浆的可行性。方法：SD雄性大鼠，每组6只，分别用苯巴比妥（PB）、β-萘黄酮（βNF）和多氯联苯（PCB）3种诱导剂，在不同给药途径、不同剂量、不同时间、单一诱导或联合诱导等7种不同诱导方式下，制备肝匀浆，并在0、-20和-40℃贮存。选择2-氨基芴（2AF）、吖啶橙（AO）和环磷酰胺（CP）3种间接致突变剂在Ames试验中应用TA100、TA98或TA97，对上述诱导方式和贮存方式、贮存时间下获得的肝匀浆进行肝代谢酶活性的考察。结果：各组肝匀浆对间接致突变剂2AF、AO和CP均呈代谢活酶性阳性；加诱导剂的肝匀浆代谢酶活性比不加诱导剂的更强；联合诱导组的肝匀浆代谢酶活性比单独诱导组的更高；不同给药途径，不同诱导时间、不同诱导剂量、联合诱导与多氯联苯（PCB）诱导等，其肝匀浆代谢酶活性基本一致。加入冰冻保护剂的肝匀浆低温贮存液在4℃可贮存4周；在-20和-40℃下贮存24周代谢酶活性未明显降低。结论：PCB诱导组肝匀浆代谢酶活性与联合诱导组基本一致，均大于单独诱导组，且后者大于未诱导组；给药途径、诱导时间和剂量对肝匀浆代谢酶活性影响不大；肝匀浆低温贮存液保存于-20和-40℃环境下24周内能够保证代谢酶的活性。

Different induction and cryopreservation methods on metabolic activities of rat liver S9

OBJECTIVE: To investigate the metabolic activities of rat liver S9 after using 7 different kinds of inducting agents and cryopreservation methods. METHODS: The S9 fraction was prepared from male Sprague-Dawley rats with phenobarbital,β-naphthoflavone or PCB induction,using different routes of administration,dosage and time by the way of combination or single inducing method. The S9 fractions were stored at 0,-20 and -40℃. Three indirect mutagens were selected and used to test for mutagenicity:2-amino-fluorene(2AF),acridine orange(AO) and cyclophosphamide (CP). RESULTS: Each group of liver homogenates showed positive results when 2AF,AO and CP were used as indirect mutagens. The activity of S9 from the combined induction method was higher. S9 could be preserved with glycerinum and stored at -20 or -40℃ without obvious loss of activity. CONCLUSION: Our data showed the following levels of S9 metabolic activities:PCB induced group=combination induced group >single induced group >non-induced group. The different routes of administration,dosage and time had little influence on the activity of S9. The S9 fraction retained good activities after storage in -20 and -40℃.