Investigating protective effects of Naoxintong Capsule on myocardial ischemia reperfusion injury by integration effect and dose–response metabolomics

Objective Naoxintong Capsule (NXT) is a core drug commonly used in clinical treatment of cardiovascular and cerebrovascular diseases in China, which is based on Buyang Huanwu Decoction. However, the protective effect and dose–effect relationship of NXT on myocardial ischemia–reperfusion injury (MIRI) are unclear, so this study aimed to evaluate the cardioprotective effect of NXT and its potential mechanism, and explore its optimal dosage. Methods Sprague-dawley male rats received trimetazidine (20 mg/kg), NXT (0.08, 0.16, 0.32, 0.64 and 1.28 g/kg), or an equal volume of saline for seven days prior to MIRI induction via intragastric administration. The MIRI model was established by occluding the left anterior descending coronary artery for a duration of thirty min, followed by a two-hour reperfusion period. The dose–effect relationship and related mechanism of NXT protecting MIRI were investigated by integration effect and dose–effect metabolomics which based on multi-indicator composite index method. Results NXT could protect MIRI by improving cardiac function, decreasing myocardial injury indexes, reducing myocardial hypertrophy and infarct area, and ameliorating structural abnormalities. Through integration effect, it was found that the dose–effect relationship showed a bidirectional correlation of first increasing and then decreasing, and the best protective effect was achieved at 0.32 g/kg, and the differential metabolites induced by MIRI could be reversed to the greatest extent in this dose. More importantly, NXT could protect MIRI by intervening in a variety of metabolites, such as stearoyl-CoA, linoleoyl-CoA, glucosamine 6-phosphate, myricetin, and 4-chlorocatechol. Conclusion In this study, the integration effect and dose–effect metabolomics based on the multi-indicator composite index method were used to illustrate the NXT’s effect on MIRI, and it was found that the potential molecular mechanism of NXT’s dose–response effects was associated with seven key metabolic pathways and the nuclear factor- κ B (NF- κ B)/nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3)/cystein-asparate protease-1 (Caspase-1)/gasdermin D (GSDMD) signaling pathway. So this study revealed the effect from the dual perspectives of metabolites and targets. Furthermore, the optimal dose of 0.32 g/kg that this study discovered may provide a certain reference for the application of NXT in cardiovascular diseases. These findings revealed the dose–effect characteristics and related mechanisms of NXT in MIRI for the first time, and provided a new insight for the prevention and treatment of MIRI.