Objective To assess the neurotoxicity of calcium carbonate nanoparticles (nano-CaCO3) by observing the changes in spontaneous activity and learning and memory of rats with subchronic exposure to nano-CaCO3.
Methods Fifty healthy male SD rats were randomly divided into a solvent control group (saline), a micro-CaCO3 group (200 mg/kg), and three nanoCaCO3 groups (12.5, 50, and 200 mg/kg), 10 rats in each group. The test substances were administered to rats by nasal instillation five times per week for twelve weeks. Open field test and Morris water maze were performed to test the spontaneous activity and the le arning and memory ability of rats.
Results Depression was found in the rats exposed to micro-CaCO3 or nano-CaCO3. There was no significant difference in body weight and brain-to-body weight ratio among all groups (P>0.05). The results of open field test showed no significant differences in time spent in center, total distance traveled, and times of vertical activity among all groups (F values were 0.799, 0.623, and 0.251, all P>0.05). The results of Morris water maze showed no significant differences in average escape latency, average path length, times of passing through platform, and residence time in platform quadrant among all groups (F values were 0.475, 0.345, 0.046, and 0.252, all P>0.05).
Conclusion No obvious damage to spontaneous activity and learning and memory of rats exposed to nano-CaCO3 is found in this experiment setting.
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