L-theanine prevents acute alcoholic heart injury by regulating helper T cell balance and cardiac metabolites in mice

Acute alcohol consumption induces oxidative stress, triggers inflammation, and disrupts the immunity balance in the heart. L-theanine (LTA) possesses antioxidant, anti-inflammatory, and immune-regulating properties. This study aimed to investigate the effects of LTA on acute alcoholic heart injury in C57BL/6J mice, which were administered varying doses of LTA followed by a single high dose of edible alcohol. The findings demonstrated that LTA mitigated acute alcoholic heart injury by maintaining immune balance, enhancing antioxidant enzyme activity, and reducing indicators of heart injury and inflammation in the mice. RNA-seq and qPCR analysis revealed that LTA intervention down-regulated key mRNAs related to T cell receptor, Th1/Th2 cell differentiation, and Th17 cell differentiation signaling pathways activated by acute alcohol intake. LTA regulated the expression levels of key proteins involved in T cell receptor and helper T cell differentiation signaling pathways, thereby maintaining the Th1/Th2 and Th17/Treg cell balance. Non-targeted metabolomic analyses indicated that LTA increased the levels of beneficial metabolites in the hearts of the mice. These results provide evidence for the preventive effects of LTA on acute alcoholic heart injury.