Purpose: The purpose of this study was to evaluate the toxicity of CN toward intestinal epithelial cells, Caco-2 cells, and an animal model, C. elegans.
Methods: Four types of CN were prepared by cross-linking of chitosan. Two cross-linkers, sodium sulfate (SS) and tripolyphosphate (TPP), and two types of chitosan, low and high molecular weight, were used to generate CN. Caco-2 cells were treated with 0.1, 0.2 or 0.4% CN for 24 h. The morphological change of the cells was checked immediately following treatment. Cellular membrane damage was assessed by lactate dehydrogenase (LDH) assay. In addition, the four types of CN from 0.1 to 0.4% were administered to C. elegans for survival assay. The viability of C. elegans was monitored every two days for 22 d.
Results: No change in cell morphology or cell viability was observed in Caco-2 cells treated with CN compared to the control. However, we observed a mild level of toxicity in the animal model. In the C. elegans survival assay, CN generated with TPP showed lower toxicity compared to the ones generated with SS. The molecular weight of chitosan did not affect the toxicity.
Significance: This data demonstrates that CN are not toxic toward intestinal epithelial cells, but are toxic in the animal model. These results will help with future development of animal models for the risk assessment of newly developed agents.