Effects of Prenatal Nicotine Exposure on the Dental Development of Laboratory Rats ( Rattus norvegicus )

Cigarette smoking is extremely common among pregnant women. The main active ingredient in cigarettes is nicotine. Nicotine is known to have negative effects on the cardiovascular system, respiratory system and birth weight among others. Maternal smoking during pregnancy has also been found to affect dental development in the offspring. The objective of this project was to assess the dose dependent effect of prenatal nicotine exposure on dental development in humans using rats ( Rattus norvegicus ) as an animal model. We hypothesized that maternal prenatal exposure to nicotine would affect dental development in the offspring. We also hypothesized that nicotine exposure in the early developmental stages would have long lasting negative effects on dental development. Rats are an ideal animal model for this study because of their short lifespan and continuously growing incisors. To test these hypotheses, 12 female and six male Long Evans rats were purchased and bred. During the 21 days of pregnancy, dams were randomly divided into four groups (n=2, per group) and injected subcutaneously with different concentrations of nicotine hydrogen tartrate (Sigma CAS Number 65‐31‐6) as follows; group 1 received a low dose of 1 mg/kg, group 2 received a medium dose of 2 mg/kg and group 3 received a high dose of 4 mg/kg. Maternal food intake and weight gain were monitored during pregnancy. At birth, pups were raised under normal laboratory conditions and weaned after three weeks. Teeth measurements are ongoing. Measurements are taken once a week and will continue for a period of 8 weeks. The rats are anaesthetized by ether. Grooves are then made on the labial surface of the right mandibular incisor teeth by means of a jeweller's file; this procedure is repeated whenever the grooves are abraded. The distance between the groove and the free gingival margin covering the interincisal septum is measured by vernier calipers, the latter being taken as the datum point. This is repeated at intervals of 2 and 7 days. Statistical analysis The differences among groups on maternal food intake, weight gain and litter size were determined by analysis of variance. P values ≤ 0.05 were considered significant. Results There was a significant difference between the experimental groups in terms of maternal weight gain (p≤0.05). However, there was no difference among the four groups when it came to food intake. Analysis of dental development is ongoing and results will be available and ready for presentation at the annual meeting. Conclusion From the current data, high dose nicotine treatment negatively impacted weight gain during pregnancy. Compared to the control group, the high dose treatment group gained the least amount of weight and had the smallest litter size. However nicotine treatment did not seem to affect food intake. More research is underway to determine the mechanisms underlying these observations. Support or Funding Information NoneFood Intake During PregnancyWeight Gain During PregnancyThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .