Integration of heart-on-a-chip and metabolomics for understanding the toxicity-attenuating effect of ethnomedicinal...

Tiebangchui (TBC), is a well-known traditional Tibetan medicine that coexists with toxicity and effects. Highland barley wine is an effective and unique processing method to reduce TBC's toxic side effects. However, the toxicity reduction mechanism is ambiguous and needs to be explored urgently. Meanwhile, the limitations of traditional animal models and two-dimensional (2D) cell culture models urgently require the development of more reliable analytical platforms for drug detection.

The integrated metabolomics and biomimetic 3D anisotropic heart-on-a-chip were utilized to reveal the toxicity-attenuating effect of highland barley wine-processed TBC from the dual perspectives of in vitro compositional changes and in vivo toxicity mechanisms. The combination of organ-on-a-chip and metabolomics provides a powerful tool for achieving spatiotemporal control of cell growth and biochemistry, as well as rapid detection of small molecule metabolites.

Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) coupled with global natural products social molecular networking (GNPS) was utilized for the expeditious identification of chemical constituents in both raw and processed TBC products. Multivariate statistical analysis was applied to screen for differential constituents before and after processing, followed by quantification of these constituents using ultra-performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-QqQ-MS/MS). After constructing a 3D heart-on-a-chip model, the structure and function of the chip model were validated via COMSOL finite element analysis, immunofluorescence, and qPCR. Leveraging this chip model, integrating molecular biology and metabolomics was employed to further elucidate the detoxification mechanism by highland barley wine-processed TBC.

The comprehensive analytical strategies demonstrated that the loss of the toxic constituents of TBC through leaching during steeping and the esterification of diterpene alkaloids with long-chain fatty acids in highland barley wine to produce less toxic lipid alkaloids were the main mechanisms of toxicity reduction. Furthermore, a biomimetic 3D anisotropic heart-on-a-chip was fabricated to evaluate differences in cardiotoxicity before and after processing. The results illustrated that the raw TBC and aconitine caused a significant increase in the extracellular LDH level, resulting in intracellular Ca²⁺ overload, substantial ROS production, and metabolite disorders primarily associated with the tricarboxylic acid cycle. This cascade of reactions ultimately led to apoptosis; however, highland barley wine processing of TBC mitigated these cardiotoxic effects.

This work not only revealed the toxicity-reducing mechanism of highland barley wine-processed TBC but also provided a novel paradigm for drug toxicity evaluation integrating metabolomics and organ-on-a-chip technologies.