HDAC9 and acute kidney injury: All these results suggested that gut microbiota mediates the nephroprotective effects of QYG against cisplatin-induced AKI, potentially via enriching bacteria genera Akkermansia, Faecalibaculum, Bifidobacterium, and Lachnospiraceae_NK4A136_group to increase the production of SCFAs (acetic acid and butyric acid), thus suppressing HDAC expression and activity, and to reduce the accumulation of uremic toxins (indoxyl sulfate and p-cresyl sulfate), thereby alleviating fibrosis, inflammation, and apoptosis in renal tissue.