Jerome A. Roth, PhD, professor of pharmacology and toxicology at State University of New York at Buffalo (UB), will use a 4-year, $2 million grant from the National Institute for Occupational Safety and Health to study hearing loss resulting from long-term exposure to manganese and noise.
The study has important ramifications for workers exposed to manganese, especially welders. Welding
rods contain high concentrations of manganese, which is released in fumes during the process of welding. Prolonged exposure to high atmospheric levels of manganese causes neurological symptoms similar to those in Parkinson’s disease, as well as hearing impairment, according to epidemiological studies and case reports.
In vitro, manganese is toxic to auditory nerve fibers as well as spiral ganglion neurons and cochlear hair cells.
In 2011, Roth and his colleagues published a study in Neurotoxicology showing for the first time that low levels of manganese initially damage neurons and sensory hair cells in the inner ears of rats. Roth’s study seeks to understand the mechanism for manganese-induced auditory loss, with the ultimate goal of finding new treatments that could prevent the condition.
He will assess the degree of hearing impairment and histopathological damage in rats resulting from various levels of manganese alone, noise alone, and manganese combined with noise. He will also compare and evaluate resulting tissue damage and compare this to manganese levels in the separate components of the inner ear.
“We hypothesize that concurrent exposure to high levels of continuous noise will exacerbate hearing impairment and damage to the inner ear induced by manganese,” Roth says.
UB collaborators on the project include Richard Salvi, PhD; Guang-Di Chen; Dalian Ding; and Diana Aga, PhD.