Abstract: Objective  To study the effect of Polygonum cuspidatum extract on myocardial injury in mice with Mycoplasma pneumoniae infection.
Methods Totally 30 BALB/c mice were randomly divided into normal group, MP model group and Polygonum cuspidatum extract group, with 10 mice in each group. The normal group was nasally infused with normal saline, and the MP model group and Polygonum cuspidatum extract group were all nasally infected with mycoplasma bacteria solution for 3 consecutive days. Treatment started on the first day of infection and continued for 3 days. The expression level of creatine kinase isoenzyme(CK-MB), cardiac troponin(cTnI), myoglobin(Mb) and aspartate aminotransferase(AST) in serum of mice were detected by ELISA method.
Results Compared with the normal group, the levels of all the myocardial injury markers in the MP model group were significantly increased(P<0.01); compared with the MP model group, in the Polygonum cuspidatum extract group CK-MB, cTnI, Mb and AST levels were significantly down-regulated(P<0.01).
Conclusion Polygonum cuspidatum extract can decrease the levels of CK-MB, cTnI, Mb and AST, significantly improve myocardial damage in mice with Mycoplasma pneumoniae infection, and protect the heart.

Key words: Mycoplasma pneumoniae pneumonia, Myocardial injury, Polygonum cuspidatum extract, Mice