Folic acid protects against tuberculosis-drug-induced liver injury in rats and its potential mechanism by metabolomics

Observational study indicated that folic acid (FA) supplementation may protect against tuberculosis-drug-induced liver injury (TBLI). The aim is to investigate the effect and mechanism of FA on TBLI in rats. Liver injury was induced by a daily gavage of isoniazid (INH) and rifampicin (RIF) in the model and FA groups. Rats in the FA group were also treated with 2.5 mg/kg body weight FA. Rats in the control group were not treated. Eight rats were used in each group. The severity of liver injury was measured by the serum levels of hepatic enzymes and histological score. The metabolites in serum and liver tissues were analyzed by HPLC-Q-TOF-MS/MS. FA treatment significantly reduced alanine aminotransferase and liver necrosis. Seventy-nine differential metabolites in the serum and liver tissues were identified among the three groups. N-acylethanolamines, INH and RIF metabolites, phosphatidylcholines, lysophosphatidylcholines, monoglycerides, diglycerides and bile acids were regulated by FA treatment, involving key metabolic pathways, such as N-acylethanolamine metabolism, INH and RIF metabolism, liver regeneration, inflammation alleviation and bile acid metabolism. RT-PCR and western blotting results confirmed the altered N-acylethanolamine metabolism and improved drug metabolism by FA. In conclusion, FA was protective against TBLI, which may be related to the regulation of N-acylethanolamine metabolism and drug detoxification by FA.