The Lack of an Ovarian Effect of Lifetime Talc Exposure in F344/N Rats and B6C3F1 Mice

There has been some concern reported about the perineal exposure to talc and the occurrence of ovarian cancer in women, although other studies have failed to find such an association. Talc particles have also been reported to be present in the ovaries of women regardless of history of talc exposure. An NTP study of lifetime whole body exposure talc exposure offered the opportunity to determine whether rodents would have ovarian talc particles after inhalation, oral, and dermal exposure for more than 2 years. Male and female Fisher 344/N rats and B6C3F1 mice were exposed to aerosol concentrations of 0, 6, or 18 mg/m super(3) of talc for lifetime (rats) or 2 years (mice). There were no exposure-related lesions in the ovaries of rats or mice however, because of the concern of potential effects of talc on the ovary, additional studies were performed. Ten female rats were selected randomly from the control and exposure groups of 6 and 18 mg/m super(3), and the histological slides containing the lungs and ovaries were examined under polarized light for the presence of anisotropic material consistent with talc particles. The lungs from the controls were negative for anisotropic materials but talc particles were easily identified from the lungs of the exposed animals. The particles were present in the alveolar macrophages and in areas associated with chronic inflammation in the lungs. There was no material consistent with talc found in the ovaries or ovarian bursa from any rats from any group. This would suggest that extensive lifetime exposure to talc does not result in the deposition of talc in the ovary. Since the animals were exposed for 6 hr per day with talc covering the fur and the cage bars, there was ample opportunity for perineal as well as oral and respiratory exposure. In the extrapolation of these data one should consider limitations relative to the marked anatomical and physiological differences between rodents and humans.