In vitro and in vivo safety evaluation of low molecular weight chitosans prepared by hydrolyzing crab shell chitosans with bamboo shoots chitosanase

[Display omitted] •LMWC did not induce chromosome aberration in doses up to 5.0mg/ml in vitro.•LMWC did not induce an increase in micronucleus ratios in mice.•No acute lethal effect at a dose of 5gLMWC/kgbw in rats.•The no observed adverse effect level (NOAEL) of LMWC is greater than 1.0g/kgbw in rats. Our previous study demonstrated that the oral administration of low molecular weight chitosans (LMWC), prepared by hydrolyzing crab shell chitosans with bamboo shoots chitosanase in an appropriate dose, reduced aristolochic acid-induced renal lesions in mice. The objectives of this study were to evaluate the safety of LMWC using genetic and animal toxicity assays. Two assays for genotoxicity were performed: the chromosomal aberration of Chinese hamster ovary cells (CHO-K1 cells) (in vitro) and micronucleus assays in mice (in vivo). Acute oral toxicity and 28-day repeated feeding toxicity tests were performed via the oral gavage method in Sprague–Dawley (SD) rats. LMWC did not induce an increase in micronucleus ratios in vivo, and the chromosome aberration assay indicated that the LMWC was safe in terms of clastogenicity in doses up to 5.0mg/ml. No acute lethal effect at a maximum tested dose of 5.0gLMWC/kgbody weight (bw) was observed in rats. The results of the 28-day study revealed no adverse effects on the body weight, feed consumption, hematology, blood biochemical parameters, organ weights or pathology. The no observed adverse effect level (NOAEL) of LMWC in rats was 1.0g/kgbw for the subacute toxicity study.