Effects Of Mifepristone Used For Labor Induction On Ultrastructure Of Myocardial Tissue Of Maternal Rats And Their Offsprings

Pu rp osc:The effects of mifepri5tonc on the rnorpho1ogica1 and stcreological feature5 of ratmyocardial tissue werc investigatcd by transmission e1ectron microscopy andstereological techno1ogy.Methods:20 Wistar pregnant rats were divided randomly into mifepristone group andcontro1 group of short term team and long term team. In the 20th gestational day, eachrat ofmifepristone group was fed mifepristone l l .5mgi lmg, whi1e the rat of controlgroup was fed sesame oil lm1. Rats of short term team were put to death in the 24hafier 1abor while myocardial tissue were investigated by transmission electronmicroscopy and stereo1ogical evaluted, Rats of long 1ong term team were put to deathin the 90 days after labor and their myocardial tissues were investigated by trans-mission e1ectron thecroscopy.Results:1. Comparing with the control group, the maternal rat myocardia1 tissue of shortterm mifepristone group displayed the following ultrastruCtural change f In somemuscle ce1ls, cytoplasm was edematous, mitochondria were markedly swollen anddisp1ayed a vacuole-like appearance or disrupted, myofilaments were disorderedor ruptured, some myQfi1aments became flocl:y and showed nu cross striations,interstitium was edematous. The volume density and mean volume of mito-chondria in muscle cells increased obviously but the numerical density showed nosignificant change.2. Comparing with the contro1 group, the new borne rat myocardia1 tissue of shortterm mifepristone group disp1ayed the fOllowing ultrastructura1 changet In somemuscle cells, cytoplasm was edematous, mitochondria were markedly swol1en,and glycogen particles, some myofilaments were disordered or ruptured, plasmamembrane showed a fOld-or ho1low-like appearance, interstitium was edematous.The volume density and mean volume of mitochondria in muscle ceIls increasedobvious1y, but the numerical density decreased obvious1y3. CompaIing with the contro1 group, the long term effects of mifepristone on themorphologica1 features of materna1 rat myocardial tissue displayed no obviouschange, the 1ong term effects of mifepristone on the u1traStructure of new bornemyocardial was proliferation ofinterstitial connective tissue.Conclusions:Mifepristone used fOr labor induction in term pregnancy can affect theultrastructure of maternal rat and new borne rat myocardia1 tissue and cause a 1ongterm damage to the new borne rat myocardial tissue.