Injuries Caused by Exposure Can Lead to Long-Term Cognitive and Motor Deficits
New research from Brazil has investigated the effects of thimerosal (TM), a mercury-containing compound used as a preservative or antiseptic in certain vaccines, skin test antigens, antivenins, ophthalmic and nasal products, and tattoo inks, on young Wistar rats, which were bred to be the equivalent in age to 2-year-old children. This research specifically focused on TM exposure through vaccination and found that mercury concentrations in tissues after acute exposure to TM were similar to previous work, with the highest accumulation in the liver followed by the brain. This pattern is attributed to the liver’s role in eliminating harmful compounds and the brain’s limited retention of organic mercury. TM exposure affected the functionality of liver mitochondria, reducing ATP synthesis and potentially compromising the Electron Transport Chain (ETC). In contrast, brain mitochondria showed increased respiratory control and ATP synthesis 24 hours post-exposure, possibly indicating an adaptive response to TM damage. Furthermore, TM exposure led to oxidative stress in the brain, affecting the glutathione peroxidase system more than in the liver. This reaction could impair the brain’s antioxidant defenses, especially as the mercury species released by TM can cross the blood-brain barrier and decrease the brain’s antioxidant capacity. Additionally, the study found that TM exposure reduced acetylcholinesterase enzyme activity in the brain, indicating potential synaptic disruption. In conclusion, the study suggests that TM exposure at concentrations comparable to those from thimerosal-containing childhood vaccines can lead to neurological impairments, mitochondrial dysfunction, oxidative stress, and altered neurotransmitter levels, which may contribute to long-term cognitive and motor deficits.
