Botox can spread from the face to the brain, scientists who injected rats with the anti-wrinkle treatment say. Traces of the toxin turned up in the rats' brain stems three days after it was injected into their whisker muscles, Bloomberg reports. A dermatologist says the findings call for further investigation, although he notes that rats and humans have different physiologies.
The authors of the study, published in the Journal of Neuroscience, were experimenting to see if the muscle-paralyzing toxin could be used to treat epilepsy and were surprised to find it traveled to the rats' brains. The FDA is already probing the safety of Botox and a competitor after reports of deaths among children being treated for cerebral palsy with the drug.