Impacts of prenatal nanomaterial exposure on male adult Sprague-Dawley rat behavior and cognition

Abstract

It is generally accepted that gestational xenobiotic exposures result in systemic consequences in the adult F1 generation. However, data on detailed behavioral and cognitive consequences remain limited. Using our whole-body nanoparticle inhalation facility, pregnant Sprague-Dawley rats (gestational day [GD] 7) were exposed 4 d/wk to either filtered air (control) or nano-titanium dioxide aerosols (nano-TiO2; count median aerodynamic diameter of 170.9 ± 6.4 nm, 10.4 ± 0.4 mg/m(3), 5 h/d) for 7.8 ± 0.5 d of the remaining gestational period. All rats received their final exposure on GD 20 prior to delivery. The calculated daily maternal deposition was 13.9 ± 0.5 µg. Subsequently, at 5 mo of age, behavior and cognitive functions of these pups were evaluated employing a standard battery of locomotion, learning, and anxiety tests. These assessments revealed significant working impairments, especially under maximal mnemonic challenge, and possible deficits in initial motivation in male F1 adults. Evidence indicates that maternal engineered nanomaterial exposure during gestation produces psychological deficits that persist into adulthood in male rats.

Figure

Behavioral and Cognitive Testing Outcomes (Mean ± SEM). a) Average time (sec) to Visible Platform. Animals exposed to nano-TiO₂ during their prenatal development had longer latencies to the visible platform than unexposed controls (* indicates p<0.05). b) Time (s) to Visible Platform across trials. On the final test trial, the effect was not significant. c) Working Memory Correct Errors within the Water Radial Arm Maze (WRAM). Animals exposed to prenatal nano-TiO₂ committed more working memory correct errors than unexposed controls (* indicates p<0.05), especially on the trial of the highest working memory load (* indicates p<0.05; insert). d) WRAM Working Memory Incorrect Errors. There were no group differences. e) WRAM Reference Memory Errors. There were no group differences.