Effect of thimerosal on the neurodevelopment of premature rats

Background: This study was undertaken to determine the effect of thimerosal on the neurodevelopment of premature rats. Methods: Thimerosal was injected into premature SD rats at a dose of 32.8, 65.6, 98.4 or 131.2 mu g/kg on postnatal day 1. Expression of dopamine D4 receptor (DRD4) and serotonin 2A receptor (5-HT2AR), apoptosis in the prefrontal cortex on post-injection day 49, and learning and memory function were studied and compared with those in a control group injected with saline. Results: Expression of DRD4 and 5-HT2AR and learning function decreased, and apoptosis increased significantly in the 131.2 mu g/kg group (P<0.001). Memory function was significantly impaired by 65.6 (P<0.05), 98.4 and 131.2 mu g/kg (P<0.001). Conclusions: The negative adverse consequences on neurodevelopment observed in the present study are consistent with previous studies; this study raised serious concerns about adverse neurodevelopmental disorder such as autism in humans following the ongoing worldwide routine administration of thimerosal-containing vaccines to infants.