Changes in Rats' Gut Microbiota Composition Caused by Induced Chronic Myocardial Infarction Lead to Depression-Like Behavior

Depression is common among patients who have chronic myocardial infarction (CMI). Despite their frequency, depression and CMI are bidirectional related conditions, each is a risk for the other, and they often co-exist, suggesting shared or interacting pathomechanisms. Accumulating data revealed the effects of gut microbiota in terms of regulating depression via the gut-brain axis. Thus, we investigated the role of gut microbial dysbiosis in CMI-induced depression-like behavior. Hierarchical cluster analysis of sucrose preference test (SPT) results was adopted to classify the CMI rats into depression-like behavior (CMI + Dep) or non-depression-like behavior (CMI + Non-Dep) phenotypes. First, 16S ribosomal RNA sequencing analysis showed both beta-diversity and relative abundance of several gut bacteria significantly differed between the CMI + Dep and CMI + Non-Dep rats. Next, transplantation of fecal microbiota from CMI + Dep rats visibly altered the relative abundance of gut microbiota and also induced depression-like behavior in the antibiotics-treated pseudo-germ-free rats. In conclusion, these findings suggested that dysbiosis in gut microbial composition contributed to the onset of CMI-induced depression-like behavior and that exogenous regulation of gut microbiota composition could be a potential therapeutic strategy for CMI and related depression-like behavior.