Morphological alterations in C57BL/6 mouse intestinal organoids as a tool for predicting chemical-induced toxicity

Intestinal organoid may serve as an alternative model for toxicity testing. However, the linkage between specific morphological alterations in organoids and chemical-induced toxicity has yet to be defined. Here, we generated C57BL/6 mouse intestinal organoids and conducted a morphology-based analysis on chemical-induced toxicity. Alterations in morphology were characterized by large spheroids, hyperplastic organoids, small spheroids, and protrusion-loss organoids, which responded in a concentration-dependent manner to the treatment of four metal(loid)s including cadmium (Cd), lead (Pb), hexavalent chromium (Cr-VI), and inorganic trivalent arsenic (iAs-III). Notably, alterations in organoid morphology characterized by abnormal morphology rate were correlated with specific intestinal toxic effects, including reduction in cell viability and differentiation, induction of apoptosis, dysfunction of mucus production, and damage to epithelial barrier upon repeated administration. The benchmark dose (BMDL10) values of morphological alterations (0.007-0.195 mu M) were lower than those of conventional bioassays (0.010-0.907 mu M). We also established that the morphologic features of organoids upon Cd, Pb, Cr-VI, or iAs-III treatment were metal specific, and mediated by Wnt, bone morphogenetic protein, apoptosis induction, and Notch signaling pathways, respectively. Collectively, these findings provide novel insights into the relevance of morphological alterations in organoids to specific toxic endpoints and identify specific morphological alterations as potential indicators of enterotoxicity.

Automated summary

Intestinal organoids can be used as an alternative model for toxicity testing, but the relationship between specific morphological changes in organoids and chemical-induced toxicity needs further exploration. In this study, we generated mouse intestinal organoids and analyzed the morphological changes induced by four metals (cadmium, lead, hexavalent chromium, and trivalent arsenic). These morphological alterations were concentration-dependent and correlated with specific intestinal toxic effects. The benchmark dose values of morphological alterations were lower than those of conventional bioassays. We also found that the morphological features of organoids were metal-specific and mediated by different signaling pathways. These findings provide valuable insights into the relevance of morphological alterations in organoids to specific toxic endpoints.