Abstract: BACKGROUND: Acupuncture at Xinshu (BL 15) can significantly improve cardiac function and protect myocardial cells in acute myocardial ischemia, but the effect and mechanism of thread embedding treatment at Xinshu (BL 15) on cardiac function in acute myocardial ischemia are yet unclear. Nuclear factor κB activation often appears as an intranuclear translocation of the P65 isoform, and activation of the nuclear factor κB signaling pathway is marked by elevated P65 levels.
OBJECTIVE: To explore the effects of thread embedding pretreatment at Xinshu (BL 15) on cardiac function and the expression levels of interleukin-10, tumor necrosis factor-α, P65 genes and proteins in rats with acute myocardial ischemia.
METHODS: Thirty-two male Sprague-Dawley rats were randomly divided into a blank group, a model group, a Xinshu (BL 15) acupoint group, and a non-meridian/non-acupoint group using a random number table method, with eight rats in each group. Rat models of acute myocardial ischemia were established in the latter three groups. The Xinshu (BL 15) acupoint group had thread embedding at Xinshu (BL 15) for 14 days, followed by subcutaneous injection of isoproterenol hydrochloride into the back to establish an acute myocardial ischemia rat model. The non-meridian/non-acupoint group had local thread embedding for 14 days, and the rest procedures were the same as above. In the model group, Xinshu (BL 15) was only marked, and the rest procedures were the same as above. In the blank group, Xinshu (BL 15) was only marked, and then an equal amount of physiological saline was injected subcutaneously into the back. After 24 hours of modeling, electrocardiogram and cardiac ultrasound were performed. Abdominal aorta blood was extracted for detection of serum creatine kinase and creatine kinase isoenzyme levels using enzyme-linked immunosorbent assay. Subsequently, the rats were euthanized and samples were collected. Hematoxylin-eosin and TUNEL staining were used to observe the pathological changes of myocardial tissue and the apoptosis of myocardial cells. Real-time fluorescence quantitative PCR (RT-qPCR) and western blot were used to detect the mRNA and protein expression of tumor necrosis factor-α, interleukin-10, and P65 in myocardial tissue respectively.
RESULTS AND CONCLUSION: (1) Electrocardiogram: Compared with the blank group, the model group, non-meridian/non-acupoint group, and Xinshu (BL 15) acupoint group had significantly elevated ST segment in lead II of the electrocardiogram. (2) Cardiac ultrasound: Compared with the model group, the Left ventricular end-systolic dimension in the Xinshu (BL 15) acupoint group were significantly reduced (P < 0.05), while left ventricular ejection fraction and left ventricular fractional shortening rate were significantly increased (P < 0.05). (4) Serum creatine kinase and creatine kinase isoenzyme: Compared with the model group, the Xinshu (BL 15) acupoint group showed a significant decrease in serum creatine kinase and creatine kinase isoenzyme levels (P < 0.05). (4) Hematoxylin-eosin staining: Compared with the model group, the arrangement of myocardial fibers in the Xinshu (BL 15) acupoint group was basically neat, with less edema and a small amount of inflammatory cell infiltration. (5) TUNEL staining: Compared with the model group, the fluorescence intensity of myocardial cell apoptosis in the Xinshu (BL 15) acupoint group was significantly reduced, and its apoptosis rate was significantly reduced (P < 0.05). (6) RT-qPCR and western blot: Compared with the model group, the myocardial tissue interleukin-10 level in the Xinshu (BL 15) acupoint group was significantly increased (P < 0.05), while tumor necrosis factor-α and P65 levels were significantly decreased (P < 0.05). These findings indicate that thread embedding pretreatment at Xinshu (BL 15) can improve cardiac function in rats with acute myocardial ischemia, and its mechanism of action may be related to the inhibition of the activation of the nuclear factor-κB signaling pathway.

Key words: Xinshu (BL 15), acupoint embedding, acute myocardial ischemia, nuclear factor-κB, isoproterenol, cardiac function, P65, interleukin-10, engineered tissue construction