Objective 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. Methods 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 14

(th)

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. Results 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 14(th) 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. Results 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 14

(th)

day after AMI(P

<

0.01). The ICM of BL14 in AMI model group was significantly decreased on the 14(th) day after AMI(P

<

0.01). The ICM of BL14 in AMI model group was significantly decreased on the 14

(th)

day than that on the 7(th) day than that on the 7

(th)

day after AMI. Compared with the normal group

the ICM of BL14 was significantly increased in AMI model group on the 7(th) day after AMI. Compared with the normal group

the ICM of BL14 was significantly increased in AMI model group on the 7

(th)

day after AMI(P

<

0.05). There were no significant changes in DM

ICM

SOAM and MVD at other acupoints on the 7(th) day after AMI(P

<

0.05). There were no significant changes in DM

ICM

SOAM and MVD at other acupoints on the 7

(th)

and 14(th) and 14

(th)

day(P

>

0.05) among the three groups.Conclusion 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.