Histomorphological evaluation of maternal and neonatal distal airspaces after maternal intake of nanoparticulate titanium dioxide: an experimental study in Wistar rats.

This study was performed to determine the histomorphological alterations occurring in maternal and neonatal pulmonary distal airspaces of Wistar rats after maternal administration of titanium dioxide nanoparticles (TiO2 NPs). Thirty adult pregnant rats (150-250 g) and their offspring were used in this study. Pregnant rats were randomly divided into control (n = 15) and TiO2 NP-treated (n = 15) groups. A suspension of TiO2 NPs in phosphate-buffered saline was given orally to the treated group (0.1 ml/10 g body weight once daily) from days 6 to 12 of gestation. At term, maternal and neonatal lungs were collected and processed for energy-dispersive X-ray (EDX) and histological analysis. The mean linear intercept (MLI) and airspace wall thickness were measured by a stereological procedure with image analysis to assess alveolarization. EDX analysis demonstrated the presence of TiO2 in maternal and neonatal lungs. The lungs of TiO2 NP-treated mothers revealed evidence of pneumocytic apoptosis, abnormal lamellar inclusions, and macrophage and inflammatory cell infiltrates. Significant thinning of alveolar septa was detected in the treated rats (p < 0.001), but the MLI was constant in both groups (p = 0.207). Neonatal lungs from treated mothers revealed deficient septation, thickened mesenchyme between the saccules, pneumocytic apoptosis, atypical lamellar inclusions, and macrophage infiltration. The thickness of the primary septa was significantly increased (p = 0.001) with no significant change in MLI (p = 0.579) compared with the control group. In conclusion, TiO2 NPs were detected in maternal and neonatal lungs after oral intake by pregnant rats. The pulmonary response manifested as inflammatory lesions and delayed saccular development in neonates.