小鼠敌敌畏经口中毒及二乙酰单肟对小肠羧酸酯酶的体内外重活化作用

Reactivating effecf of diacetyl monoxime on mouse small intestine carboxylesterase inhibited by dichlorvos in vitro and in vivo

目的：研究二乙酰单肟（ｄｉａｃｅｔｙｌｍ ｏｎｏｘｉｍ ｅ，ＤＡＭ）对敌敌畏体内外抑制小鼠小肠羧酸酯酶重活化的作用。方法：用微量对硝基酚戊酸酯法测定ＤＡＭ 对敌敌畏体内外抑制的小鼠小肠羧酸酯酶的重活化作用。结果与结论：１，０．５，０．１ ｍ ｍ ｏｌ／Ｌ的ＤＡＭ 在体外对敌敌畏抑制的小鼠小肠羧酸酯酶有较强的重活化作用（重活化率分别为８４．８％ ，５９．３％ 和３２．４％ ），而对正常小肠羧酸酯酶没有抑制作用，但ＤＡＭ 经口、肌肉和腹腔给药（均为１００ ｍ ｇ／ｋｇ 体重）在整体对小鼠敌敌畏经口中毒（１００ ｍ ｇ／ｋｇ 体重）没有显著的抗毒作用，对小鼠敌敌畏５０ ｍ ｇ／ｋｇ 体重经口中毒后小肠羧酸酯酶的抑制也没有显著的重活化作用（Ｐ＞ ０．０５）；而且ＤＡＭ 经口与腹腔给药后小鼠小肠羧酸酯酶活力显著下降（Ｐ＜ ０．０５），但ＤＡＭ 经肌肉给药后小鼠小肠羧酸酯酶活力没有显著变化，从而提示ＤＡＭ 经口、肌肉与腹腔给药都不能有效地对抗敌敌畏对小鼠的毒性，其本身经口与腹腔给药后对小肠羧酸酯酶的抑制作用可能与肝肠首过效应有关。

Objective: To investigate the reactivating of diacetyl monoxime (DAM) on mouse small intestine carboxylesterase (CaE) inhibited by dichlorvos(DDVP) in vitro and in vivo. Methods: A p nitrophenol valerate microassay method for CaE activity was used to determine the reactivating effect of DAM on mouse small intestine CaE inhibited by DDVP in vitro and in vivo. Results and Conclusion: The reactivation percentages of DDVP inhibited mouse small intestine CaE induced by DAM at 1,0.5 and 0.1 mmol/L in vitro were 84.8%,59.3% and 32.4%, respectively. It did not inhibit the normal small intestine CaE. Administration of DAM po, im or ip at 100 mg/kg body weight did not exhibit significant antitoxic effect on mice intoxicated by DDVP po at 100 mg/kg body weight and also did not induce significant reactivation of small intestine CaE in mice intoxicated by DDVP po at 50 mg/kg body weight (P>0.05). Furthermore, DAM po and ip at 100 mg/kg body weight could decrease small intestine CaE activity significantly in normal mice (P<0.05). These results suggested that administration of DAM po, im or ip does not have significant antitoxic effect on mice intoxicated by DDVP po. The inhibitory effect of DAM itself on mouse small intestine CaE activity may be related to its metabolism in liver and intestine.