The aim of the present study was to demonstrate the possible effect of the commercial Metronidazole MTZ (Flagyl®) on the implantation of embryo in the pregnant rat’s uterus (Rattus norvegicus).The days 7 and 9 days post coitum were chosen as representative days for early pregnancy. For that purpose, 64 female rats were selected for the present experiment. All the experimental rats were given oral daily different dosage of the drug, which include: 9mg\200 gm body weight (BW); double that dosage (18mg\200 gm BW); and triple the first dose (27 mg\200 gm BW) for seven days and nine days respectively. The former two days were taken as the base upon in which the results of the present work were depicted.
The histological and physiological results of the present work was clearly shown that the implantation of Blastocyst has occurred in the antimesometrial side of endometrium and at 7dpc most of its will modified to Decidual tissue as in all types of placentation. The anti mesometrial decidual tissue was divided in the present work into primary decidual zone, secondary decidual zone, implantation zone, and undifferentiated decidual zone. The uterine glands were noticed to be affected by process of implantation; they have enlarged in size and have become more tortuous. It was clearly shown that primary decidual tissue was devoid of collagen fibers while the secondary decidual tissues were having spars fibers. Most of the fibers were concentrated mainly in the mesometrial decidual tissue at day 9 dpc and exactly alongside the spiral arteries which supply the placenta with maternal blood. Another prominent observation of the present work was the migrating trophoblast cells from the embryo to mother.
The results statically revealed that taking treatment and double dose MTZ for 7 dpc group cause decrease the level value of Estradiol hormone in blood serum but this decrease was not significant p>0.05 but it was significant p<0.05 at the triple dose .This result was confirmed by the correlation factor (r) between MTZ and Estradiol hormone which was not significant p>0.05 inversely for 7dpc and significant p<0.05 for 9 dpc, and for Progesterone was cause significant p<0.05 decrease the value of blood serum level, the correlation factor (r) between MTZ and Progesterone hormone was significant p<0.05 inversely. The effect of the three doses of MTZ on uterine size revealed no significant effect p>0.05, but there was significant effect p>0.05 of pregnant period on the size, the correlation factor (r) was right in 7dpc and reverse un significant p>0.05 for 9dpc, and for the effect of MTZ on the diameter of uterus for 7 and 9dpc revealed no significant effect p>0.05 for the three dosages and there was significant differences between the treatments. There was no significant p>0.05 decrease in the numbers of embryos at the three dosages, and the correlation factor (r) was inversely and there was no significant differences p<0.05 between the treatments. The results revealed to significant p<0.05 right correlation between progesterone and uterine size, weight, and number of fetuses.
The histological results of the present work together with the analysis of the results statistically were in favor of considering that there was no harmful effect of the drug MTZ on the process of implantation on days 7 and 9dpc.