Fig. 4

P. loescheii colonization and butyrate supplementation alleviate PD-1/PD-L1 inhibitor-related cardiotoxicity. In the B16F10 melanoma model, the mice were intraperitoneally administered with the PD-1/PD-L1 inhibitor BMS-1 (0, 5 and 10 mg/kg) every 2 days for 6 times (n = 4). A Significant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways at level 3 for the fecal microbiome of BMS-1 (10 mg/kg) and the control group were identified by STAMP software. B The levels of SCFAs in the feces were determined by HPLC. C In the B16F10 melanoma model, the C57BL/6 mice were orally administrated with Prevotellaceae loescheii (P. loescheii) (1 × 10⁸ CFU/mouse/every 2 days) or sodium butyrate (1 g/kg) for 1 week during BMS-1 (10 mg/kg) treatment (n = 10). D The relative level of P. loescheii. E The level of butyrate in the feces was determined by HPLC. F The serum levels of creatine kinase-MB (CK-MB), aspartate transaminase (AST), creatine kinase (CK) and lactate dehydrogenase (LDH). G Representative images of TUNEL assay of cardiac tissues and corresponding quantification analysis. Scale bars, 50 μm. The values are presented as the mean ± standard error of the mean. ^*P < 0.05, ^**P < 0.01 vs. control or BMS-1