OCLN and hydrops fetalis: After trimetazidine treatment, as compared to untreated HF rats, the TMZ group showed a certain degree of improvement in myocardial and colonic tissue lesions, a significant increase in ZO-1 and occludin protein expression, a notable rise in the gut microbiota health index, a decrease in the dysbiosis index, an increase in OTUs, and a recovery of species richness and diversity, though the improvement in microbiota structure was not significant.