Abstract: The article mainly research the toxic effects of diquat on dutus arteriosus of rat fetus and the mechanism of toxic effects.Method:①Put gravid Wistar rat as research target .Eight gravid female Wistar rats on each day 19,20,21of gestation wererespectively divided randomly into two groups ,4 rats per group.In the experimental group, the rats were administered withdiquat by subcutaneous injection at the dose of 7.0 mg/kg. In the control group , the rats were administered with saline bysubcutaneous injection. The all animals were sacrificed 3h after injection .Three fetuseswere used for observing contraction ofductus arteriosus per gravid rat .Result: The internal diameter of ductus arteriosus of fetuses of rat dams treated with diquat wassignificantly decreased than that in the control group. The critical contraction time of ductus arteriosus of rat’s futus induced bydiquat is between 19d and 20d. This article still research the mechanism of the Toxic effects of diquat on dutus arteriosus of ratfutus through in vitro and in vivo experiment .②By in vitro experiment, get 0.5mg powder from the microsome of sheepspermatophore,1μmol/L hemachrome of cattle ,50μmol/L(1-C14)arachidonic acid ,1mmol/L diquat. Ensure the volume is 0.1 mland hold it for 1min under 24℃.Then join 0.3ml mixture of B ether , ethyl alcohol and 1mol/L critic acid(30:40:1), stop thereaction and join 0.5g pyrotechnite . Then put 50μl organic solvent level on the silicagel F254 glass plate. At the mean time , tipthe PGB1 on the former glass then outspread 15cm in the mixture of B ether ,petroleum benzin, acetic acid(85:15:1). Afterpunctuating the position of PGB1, fix them on X ray pellicle for 48h and take auto radiation pictures. Confirm the outspreadingposition of radiation resultant and tanscribe the outspreading part of arachidonic acid , PGG2 and PGH2.Mensurate eachradioactivity with liquid spectro analysis of isotopes and do the same experiment with 0.01μmol/L～1mmol/L indomethacin,then compare them. Result: The creation of PGG2 and PGH2 has nothing to do with diquat . In other words, the creation of PGG2and PGH2 is almost equal to the control group.③by in vivo experiment , divided randomly 21d gravid Wistar rats into 2 groups,16 rats per group. The rats in the experiment group were administered with diquat by subcutaneous injection at a dose of 7.0 mg/kg .The rats in the control group were administered with saline by subcutaneous injection .Take 8 gravid rats on 3h after injection,dissect them afrer anaesthetizing by B ether and sample blood from abdomen arteriosus. Then get 4 fetuses per gravid rat andcut the arm pit, sample blood. The control group take the same way. Observe PGE2 content in plasm of the fetus. Result: Thein vivo experiment more prove the contraction of ductus arteriosus of rat’s fetus induced by diquant isnot related to PGE2. Thatis to say, the contraction of ductus arteriosus for rat’s fetus induced by diquat isn’t accomplished by preventing the composionof PGE2. Conclusion: Diquat affects ductus arteriosus of rat fetus .And the contraction induced by diquat is not related to PGE2.That is to say, the mechanism of contraction induced by diquat is different from the mechanism of contraction induced byindomethacin.

Key words: diquat, dutus arteriosus, PGE2, indomethacin