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Published on: November 20, 2015
Lasting neuropathological changes in rat brain after intermittent neonatal administration of thimerosal
Mieszko Olczak1, Michalina Duszczyk, Paweł Mierzejewski
1Department of Pharmacology and Physiology of the Nervous System, Institute of Psychiatry and Neurology, ul. Sobieskiego 9, Warsaw, Poland.
Insights
Thimerosal, a mercury-based preservative in vaccines, caused significant brain damage in developing rats. These neurotoxic effects suggest a potential link between thimerosal exposure and neurodevelopmental disorders in children.
Area of Science:
- Neuroscience
- Toxicology
- Pediatrics
Background:
- Thimerosal, an organomercurial preservative, is used in some vaccines.
- It is a suspected factor in pediatric neurodevelopmental disorders, including autism.
Purpose of the Study:
- To investigate the neuropathological effects of early postnatal thimerosal administration in Wistar rats.
- To assess the potential link between thimerosal and neurodevelopmental disorders.
Main Methods:
- Wistar rats received four intramuscular injections of thimerosal (12 or 240 μg THIM-Hg/kg) on postnatal days 7, 9, 11, and 15.
- Brain pathology was examined in young adult rats.
Main Results:
- Thimerosal exposure resulted in numerous neuropathological changes.
- Observed effects included neuronal degeneration, blood vessel pathology, diminished synaptophysin, astroglial atrophy, and positive caspase-3 reactions.
Conclusions:
- Thimerosal exhibits neurotoxic effects in the developing rat brain at vaccine-relevant doses.
- These findings suggest a potential role for thimerosal in neurodevelopmental disorders.
Abstract:
Thimerosal, an organomercurial added as a preservative to some vaccines, is a suspected iatrogenic factor, possibly contributing to paediatric neurodevelopmental disorders including autism. We examined the effects of early postnatal administration of thimerosal (four i.m. injections, 12 or 240 μg THIM-Hg/kg, on postnatal days 7, 9, 11 and 15) on brain pathology in Wistar rats. Numerous neuropathological changes were observed in young adult rats which were treated postnatally with thimerosal. They included: ischaemic degeneration of neurons and "dark" neurons in the prefrontal and temporal cortex, the hippocampus and the cerebellum, pathological changes of the blood vessels in the temporal cortex, diminished synaptophysin reaction in the hippocampus, atrophy of astroglia in the hippocampus and cerebellum, and positive caspase-3 reaction in Bergmann astroglia. These findings document neurotoxic effects of thimerosal, at doses equivalent to those used in infant vaccines or higher, in developing rat brain, suggesting likely involvement of this mercurial in neurodevelopmental disorders.
