Protective effect of vitamin C in female Swiss mice dermally-exposed to the tannery effluent

Abstract

Previous studies involving the oral exposure of mice to tannery effluents have found neurotoxic effects. However, studies about the effects the dermal exposure to pollutant have on the cognitive function of females have not been found in the literature. Thus, the aim of the current study is to investigate whether the dermal exposure of female Swiss mice to tannery effluents (2 h/day for 20 days) can cause cognitive impairment, as it was already evidenced in male Swiss mice. Furthermore, based on the administration of vitamin C (before or after the exposure to the xenobiotic), the current study also aims to assess the protective effect of vitamin C in female Swiss mice dermally-exposed to the tannery effluent. Female Swiss mice exposed to the tannery effluent (without vitamin supplementation) have shown lower novel object recognition index during the test session of the novel object recognition task, and they have descended significantly faster from the inhibitory avoidance platform when they were compared to mice belonging to the other groups, therefore evidencing memory deficit. However, the test performance of females receiving vitamin C was similar to that of control animals. Thus, the current study confirms the initial hypothesis that the dermal exposure to the pollutant, even for a short period, causes cognitive deficit in female Swiss mice. The herein presented findings also provide evidence that the mechanisms of action of the tannery effluent in these animals are related to oxidative damages in specific brain regions directed to the formation of short memory to perform aversive and object recognition tasks.