Objective To investigate the subchronic toxicity of α-lipoic acid (ALA) on rats including target organ and no-observed-adverse-effect-levels (NOAEL).
Methods A total of 96 Sprague-Dawley rats were randomly divided into 4 groups by body weight, half male and half female. The experimental groups were fed by gavage with suspensions of 180, 90 or 45 mg/kg ALA with 1% sodium carboxymethyl cellulose (CMC-Na), and the vehicle control group were fed with 1% CMC-Na.
Results After 90 days of ALA treatment, the toxic signs of female rats in the 180 mg/kg ALA group were obvious, with 5 deaths. The alanine transaminase and the aspartate aminotransferase in the 180 mg/kg group were increased by more than 2 fold compared with the controls, indicating liver cell injury was induced. Meanwhile, histopathological examinations showed various lesions in part of the female rats in the 180mg/kg group. From the fourth week of this study, the body weight of male rats in the 90 and the 180mg/kg ALA groups were decreased significantly. In addition, no abnormality of hematological, biochemical and urinalysis determinants, weight coefficient of major organs, and histopathological examinations was found in all groups of male rats, nor in the 45 and the 90 mg/kg ALA groups of female rats.
Conclusion Liver could be the target organ of ALA by evidences of the study. The NOAEL of ALA in the 90-day oral toxicity study is 90 mg/kg for rats of both genders.
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