Photoacoustic imaging study on spatial structure of microvessels around acupoints in mice with acute myocardial ischemia

Abstract

To observe the changes of microvascular structure of acupoints caused by myocardial ischemia, so as to explore the application of photoacoustic imaging technology in the research of acupoint sensitization. Twelve BALB/c mice were randomly divided into normal, sham operation and acute myocardial ischemia (AMI) model groups, with 4 mice in each group. AMI model was established by ligating the left anterior descending coronary artery. Electrocardiogram (ECG) was recorded by physiological signal acquisition system at 12 h and on the 14th day after modeling, and serum cardiac troponin T (cTnT) and creatine kinase isoenzyme MB (CK-MB) levels were detected by enzyme-linked immunosorbent assay. The microvascular structure changes of acupoints "Feishu"(BL13), "Jueyinshu"(BL14), "Quze"(PC3) and "Chize"(LU5) were observed by photoacoustic imaging technology, and distance (DM), inflection count metric (ICM), sum of angle metric(SOAM)and microvessel density (MVD) were calculated by microvascular quantification algorithm. Compared with the normal and sham operation groups, the ST segment of ECG was obviously elevated, serum cTnT and CK-MB were significantly increased in AMI model group at 12 h and on the 14th day after AMI (P<0.01). The ICM of BL14 in AMI model group was significantly decreased on the 14th day than that on the 7th day after AMI. Compared with the normal group, the ICM of BL14 was significantly increased in AMI model group on the 7th day after AMI(P<0.05). There were no significant changes in DM, ICM, SOAM and MVD at other acupoints on the 7th and 14th day (P>0.05) among the three groups. The change of ICM may be one of the characteristics of acupoint sensitization and photoacoustic imaging technology can be used to study the structure of acupoint microvessels.