Toxicity of aristolochic acid in a rat model investigated by Fourier transform infrared spectroscopy combined with chemometric analysis: An exploratory study

Aristolochic acid is a potent carcinogenic and nephrotoxic chemical found in all Aristolochia plants and the toxicity issue of aristolochic acid has gained increasing attention in recent years. To better understand the toxicity of aristolochic acid, we here explored to use Fourier transform infrared (FTIR) spectroscopy combined with chemometric analysis to investigate the biochemical changes of the liver and kidney tissues as well as plasma of a rat model due to aristolochic acid poisoning. We first collected the FTIR spectra of the plasma and tissue samples from the treatment group and the control group of the model rats. We then performed the chemometric analysis of these FTIR spectra using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The interesting discovery was that when there was no distinctive change in the plasma samples due to aristolochic acid poisoning, there were already spectral changes in the liver and kidney samples which could be effectively distinguished by PCA and PLS-DA. Moreover, our chemometric analysis indicated that the aristolochic acid-induced damages on the liver tissue of model rats featured with lipid metabolism changes, while the biochemical changes caused by aristolochic acid on the kidney tissue seemed to be more complex. To the best of our knowledge, this work is the first application of FTIR spectroscopy combined with chemometric analysis in the investigation of the toxicity of aristolochic acid.