Broad range lipidomics and metabolomics coupled with 16S rRNA sequencing to reveal the mechanisms of Huangkui Capsule against cisplatin-induced nephrotoxicity

Ethnopharmacological relevance: Huangkui Capsule (HKC) is a traditional Chinese medicinal preparation. Numerous clinical studies have reported that HKC has a good nephroprotection effect. The clinical application of cisplatin is greatly limited by its nephrotoxicity, and HKC shows promise in preventing cisplatin-induced nephrotoxicity (CIN).

Aim of the study: To evaluate the effectiveness of HKC in alleviating CIN and explore its underlying action mechanisms.

Materials and methods: A rat model of CIN was established via single-dose injection of cisplatin. The effectiveness of HKC was evaluated by biochemical indices and pathological sections. Then, serum, kidney, and cecal endogenous metabolic profiles as well as the gut microbiota were characterized using lipidomics, metabolomics, and 16S rRNA high-throughput sequencing technique. Spearman's correlation analysis was carried out between gut microbiota, biomarkers, and biochemical indices. Finally, antibiotic treatment was performed to establish a pseudo-sterile rat model and validate the nephroprotection of HKC in a gut microbiota-dependent manner.

Results: HKC could significantly attenuate the abnormal elevation of serum creatinine and urea nitrogen, kidney index, and kidney injury score in CIN rats, remarkably alleviate the disturbance of metabolic profiles of serum, kidney, and cecal contents, corresponding to the endogenous metabolites such as fatty acids, phosphatidylcholines, amino acids, acylcarnitines, and short-chain fatty acids, and enrich the diversity of gut microbiota. Spearman's correlation analysis revealed that Clostridium_sensu_stricto_1 was positively correlated with the altered short-chain fatty acids in serum and negatively correlated with the altered acylcarnitine in the kidney. In the pseudo-sterile rat model, the attenuation effect of HKC on the abnormal elevation of serum creatinine and urea nitrogen, along with the alleviation of metabolic profile disorders, was greatly diminished or even abolished, demonstrating the nephroprotective effect of HKC in a gut microbiota-dependent manner.

Conclusions: HKC exerted the nephroprotective effect on CIN in a gut microbiota-dependent manner, mainly by regulating Clostridium_sensu_stricto_1 mediated metabolisms of phosphatidylcholines, acylcarnitines, fatty acids, tryptophan, and short-chain fatty acids, thereby reducing the inflammatory response. The present study could provide reliable scientific evidence for gut microbiota-dependent mechanisms of HKC in the treatment of kidney injury and may widen the clinical application of HKC in cisplatin-containing cancer therapy.