RESUMO
Nicotine can pass through placental blood barrier and accumulate in the developing organs of fetus. Also, entering the breast milk, nicotine can have an effect on the neonates. Investigations have showed that collagen IV is one of the most important micro vessels basement membrane components. In this study, the effect of maternal nicotine exposure in pre and postnatal periods on collagen IV in microvessels of neonatal Balb/C mice brain cortex was studied by immunohistochemistry technique. 24 pregnant Balb/C mice were divided in to 4 groups [6 mice in each group]: two experimental and 2 control groups. The mothers in the 1st experimental group were injected 3 mg/kg nicotine intrapritoneally from the 5th day of pregnancy to parturition daily and in 2nd experimental group the same procedure was repeated to the 10th day after parturition [lactation]. The control groups received the same volume of normal saline during the same time. 10 days after delivery, the brain tissues of newborns were isolated. Then, prepared blocks from fixed brain were cut serially for immunohistochemical assay. The findings of the present study indicated that collagen IV reaction in microvessels basement membrane in the first experimental group increased significantly compared to the first control group [p=0.002]. In addition, collagen IV reaction in microvessels basement membrane in the 2nd experimental group increased significantly compared to the 2nd control group [p=0.002]. However, no significant difference was observed between the two experimental groups. These results suggested that maternal nicotine exposure during prenatal period may increase basement membrane collagen IV expression. Also, nicotine increases in maternal breast milk has no effect on basement membrane collagen IV expression