Prenatal and Postnatal Nicotine Exposure Goes Beyond The Surface Level

This study looked at nicotine exposure during gestation and lactation and the effects on cardiac remodeling on rat pups. Cardiac remodeling indicates a change in the shape, size, or function of the heart. This can occur due to several factors; in this case the experimenters are looking at nicotine exposure as an element.  Sprague-Dawley rats were used for the study and they were divided into two groups, the control group and the nicotine group. There were several areas specifically examined in the offspring including heart and body weight, heart histology, collagen deposition, and immunohistochemistry for β-MHC and TGF-β1 manifestation.

            When compared to the pups that were in the saline control group, the pups that were administered nicotine had significantly lower heart and body weight. This suggests that prenatal exposure to nicotine acts as a hindrance for the fetal heart causing it to inhibit growth. The pup’s hearts were dissected and found that the cell width of cardiomyocytes (cells that form cardiac muscle) was greater in the nicotine pups. There was also an increase in collagen deposits, which is an indicator of cardiac remodeling. The nicotine group of pups showed a significantly higher β-MHC and TGF-β1 immunoreactivities compared to the control group. The study associated the increase in collagen to the increase in TGF-β1 manifestation. They concluded from these results that TGF-β1is critical in cardiac remodeling when induced with nicotine.

            The rats that had postnatal nicotine exposure in addition to prenatal nicotine exposure demonstrated an increase in the effects of nicotine exposure compared the rats that were only exposed prenatally. This is due to a higher concentration of nicotine in the breast milk compared to the serum that was injected into the dams.

            The experiment supported that pups that are exposed to nicotine during gestation and lactation can induce cardiomyocyte hypertrophy. One of the limitations of the study was the small sample size of Sprague-Dawley rats. The take home message is that prenatal and postnatal exposure to nicotine can have detrimental effects on the heart of the offspring.

Abstract

Chou, H. C., & Chen, C. M. (2014). Maternal nicotine exposure during gestation and lactation induces cardiac remodeling in rat offspring. Reproductive Toxicology, 50, 4-10. doi: 10.1016/j.reprotox.2014.09.013