Effect of Prenatal Cigarette Smoke Exposure on Maternal Fetal Barrier and its Possible Prevention

Background: Prenatal Exposure to cigarette smoke has deleterious effects on the placenta and the fetus, which may be due to toxic substances and free radicals present in smoke. The latter cause oxidative injury and therefore, the role of antioxidants need to be investigated as a possible preventive agent. Objective: To determine, the effects of cigarette smoke on maternal fetal barrier and to observe the preventive role of antioxidants if any. Materials and Methods: 51 female mice (Balb C strain) were mated and grouped: Groups C: control, S: exposed to smoke and SV: exposed to smoke and given antioxidants (vitamin C, E) and sacrificed at 19 dpc (days post coitus). 14 animals from C, 12 from S and 14 from SV had healthy pregnancies. Their placentae were studied microscopically. The thickness of the maternal fetal barrier and the distance between mononuclear trophoblast cells in the maternal sinusoids were measured. Results: The thickness of maternal fetal barrier, and the distance between mononuclear trophoblast cells in the S group (2.21±1.35μm, 38.36±2.05μm) were significantly greater than in the Control (1.31±0.04μm, 33.48±1.00μm) with P=0.0001 and P=0.01 respectively. The thickness of the barrier in the SV (1.66±0.09μm) was significantly thinner than the S group (P=0.002).The distance between mononuclear trophoblast cells in the SV did not increase significantly (33.58±1.37μm: P=0.17) as compared to the Control. Conclusion: Cigarette smoke causes thickening of the maternal fetal barrier which could be ameliorated significantly by antioxidants. Therefore, these effects may be partly due to oxidative injury produced by free radicals present in the smoke.