Effect of Prenatal Exposure to Waterpipe Tobacco Smoke on Learning and Memory of Adult Offspring Rats.

Introduction: Waterpipe tobacco smoking has increased in prevalence worldwide, including among pregnant women. In this study, we investigated the effect of prenatal maternal waterpipe tobacco smoke (WTS) exposure during different stages of pregnancy on learning and memory of adult offspring rats. Methods: Pregnant rats received either fresh air or mainstream WTS (2 hours daily) during early, mid, late, or whole gestational period. Male offspring rats were followed through 20 weeks. Outcomes included (1) spatial learning and memory using the radial arm water maze (RAWM), (2) levels of brain derived neurotrophic factor (BDNF) in the hippocampus, and (3) oxidative stress biomarkers (superoxide dismutase, catalase, glutathione peroxidase and thiobarbituric acid reactive substances). Results: Relative to offspring whose mothers were exposed to fresh air, prenatal exposure to WTS at any stage of pregnancy resulted in short- and long-term memory impairment in adult offspring rats (p < .05). This impairment was associated with reduced levels of BDNF in hippocampus (p < .05). However, prenatal WTS did not affect the level of oxidative stress biomarkers in hippocampus. Prenatal WTS during late gestation increased the activity of catalase as compared to control. Conclusion: Prenatal maternal WTS exposure can impair the memory of adult male offspring. These results support development of interventions that target pregnant women who smoke waterpipe during pregnancy. Implications: We examined for the first time the effect of prenatal waterpipe tobacco smoke exposure on learning and memory of offspring. The results showed that in utero exposure to waterpipe tobacco smoke was associated with impaired memory and decreased brain derived neurotrophic factor in hippocampus of adult male offspring rats.