Chitoheptaose Promotes Heart Rehabilitation in a Rat Myocarditis Model by Improving Antioxidant, Anti-Inflammatory, and Antiapoptotic Properties.

Background. Myocarditis is one of the important causes of dilated cardiomyopathy, cardiac morbidity, and mortality worldwide. Chitosan oligosaccharides (COS) may have anti-inflammatory and cardioprotective effects on myocarditis. However, the exact molecular mechanism for the effects of functional COS on myocarditis remains unclear. Methods. Anti-inflammatory activities of COS (chitobiose, chitotriose, chitotetraose, chitopentaose, chitohexaose, chitoheptaose, and chitooctaose) were measured in lipopolysaccharide- (LPS-) stimulated RAW264.7 cells. A rat model with myocarditis was established and treated with chitopentaose, chitohexaose, chitoheptaose, and chitooctaose. Serum COS were measured by using high-performance liquid chromatography (HPLC) in all rats. Myocarditis injury, the levels of reactive oxygen species (ROS), reactive nitrogen species (RNS), inflammatory factors, and apoptotic factors were also measured. Pearson's correlation coefficient test was used to explore the relationship between the levels of ROS/RNS and cardiac parameters. Results. Among all chitosan oligosaccharides, the COS>degrees of polymerization mml:mfenced close=")" open="("DP 4 showed anti-inflammatory activities (the activity order was chitopentaose4). The levels of ROS/RNS had a strong relationship with cardiac parameters. Conclusions. Chitoheptaose plays a myriad of cardioprotective roles in the myocarditis model via its antioxidant, anti-inflammatory, and antiapoptotic activities.