Lactobacillus helveticus and Bifidobacterium longum taken in combination reduce the apoptosis propensity in the limbic system after myocardial infarction in a rat model.

Myocardial infarction (MI) stimulates the release of pro-inflammatory substances that induce apoptosis in the limbic system. Pro-inflammatory cytokines are considered as the root cause of apoptosis, although the mechanism is not fully explained and/or understood at this time. In addition, depression may induce gastrointestinal perturbations that maintain the elevated levels of pro-inflammatory cytokines. It has been shown that some specific probiotic formulations may reduce gastrointestinal problems induced by stress and the pro/anti-inflammatory cytokine ratio. Therefore, we hypothesised that probiotics, when given prophylactically, may diminish the apoptosis propensity in the limbic system following a MI. Male adult Sprague-Dawley rats were given probiotics (Lactobacillus helveticus and Bifidobacterium longum in combination) or placebo in their drinking-water for four consecutive weeks. A MI was then induced in the rats by occluding the left anterior coronary artery for 40 min. Rats were killed following a 72 h reperfusion period. Infarct size was not different in the two groups. Bax/Bcl-2 (pro-apoptotic/anti-apoptotic) ratio and caspase-3 (pro-apoptotic) activity were reduced in the amygdala (lateral and medial), as well as in the dentate gyrus in the probiotics group when compared with the placebo. Akt activity (anti-apoptotic) was increased in these same three regions. No significant difference was observed in Ca1 and Ca3 for the different markers measured. In conclusion, the probiotics L. helveticus and B. longum, given in combination as preventive therapy, reduced the predisposition of apoptosis found in different cerebral regions following a MI.