Trichloroethylene, trichloroacetic acid, and dichloroacetic acid: do they affect eye development in the Sprague-Dawley rat?

Dichloroacetic acid-induced dysfunction in rat hippocampus and the protective effect of curcumin

The present study was designed to evaluate the role of cAMP-PKA-CREB signaling in mediating the neuroprotective effects of curcumin against DCAA-induced oxidative stress, inflammation and impaired synaptic plasticity in rats. Sixty Sprague-Dawley rats were randomly divided into five groups, and we assessed the histomorphological, behavioral and biochemical characteristics to investigate the beneficial effects of different concentrations of curcumin against DCAA-induced neurotoxicity in rat hippocampus. The results indicated that animal weight gain and food consumption were not significantly affected by DCAA. However, behavioral tests, including morris water maze and shuttle box, showed varying degrees of alterations. Additionally, we found significant changes in hippocampal neurons by histomorphological observation. DCAA exposure could increase lipid peroxidation, reactive oxygen species (ROS), inflammation factors while reducing superoxide dismutase (SOD) activity and glutathione (GSH) level accompanied by DNA damage in the hippocampus. Furthermore, we found that DCAA exposure could cause a differential modulation of mRNA and proteins (cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), cAMP-response element-binding protein (CREB), p-CREB, brain-derived neurotrophic factor (BDNF), postsynaptic density-95 (PSD-95), synaptophysin (SYP)). Conversely, various doses of curcumin attenuated DCAA-induced oxidative stress, inflammation response and impaired synaptic plasticity, while elevating cAMP, PKA, p-CREB, BDNF, PSD-95, SYP levels. Thus, curcumin could activate the cAMP-PKA-CREB signaling pathway, conferring neuroprotection against DCAA-induced neurotoxicity.

Trichloroethylene and ocular malformations: analysis of extant literature

An evaluation of the scientific literature for trichloroethylene (TCE) identified two reports of ocular defects, specifically microphthalmia/anophthalmia, following prenatal TCE exposure in rats. Herein, these reports are analyzed in detail and interpreted within the context of other developmental TCE exposure studies. The ocular findings following prenatal TCE exposure are reported in studies that were not designed specifically for developmental safety assessment, and thus did not use standard experimental practices. Furthermore, these findings most commonly occurred at TCE doses associated with considerable maternal toxicity. Among the 18 published studies using developmental TCE exposures, only 3 used doses sufficiently high enough to result in maternal toxicity, and of these, only the 2 discussed in detail in this paper demonstrated ocular defects in the offspring. Furthermore, statistically significant effects were only observed at doses that were above the currently accepted guideline limit dose of 1000 mg/kg body weight. All other TCE developmental exposure studies failed to demonstrate ocular defects as a result of prenatal exposure. These results suggest that the micro-/anophthalmia findings were likely a consequence of delivery of an extremely high bolus TCE dose that is irrelevant to human environmental exposure scenarios.