Effect and Mechanism of Action of Acupoint Injection of Puerarin on Myocardial Mitochondria Energy Metabolism in Bupivacaine-poisoned Rats

Background There is no safe and effective antidote for cardiotoxicity induced by bupivacaine, an extensively used anaesthetic. Our previous research shows that acupoint treatment may partially improve bupivacaine-induced cardiotoxicity, but the mechanism of action needs to be further studied. Objective To observe the effect of acupoint injection of puerarin on mitochondrial energy metabolism in myocardia in bupivacaine-poisoned rats, and to explore its mechanism of action. Methods This experiment was conducted from January to December 2019. Forty 6-month-old male SPF Wistar rats were selected and equally randomized into a blank group (group C) , a model group (group B) , a treatment group (group T) , and a prevention group (group P) . Interventions were given to the groups as follows: Group P received: 0.1 ml puerarin injection injected into bilateral Neiguan acupoints. Then 5 minutes later, bupivacaine-poisoned model was established for three groups (except for group C) using intravenous infusion of 0.5% bupivacaine (10 mg/kg) via femoral vein within 2 minutes. Group C received 0.1 ml of 0.9% sodium chloride solution injected into bilateral Neiguan acpoints. : Immediately after successful modeling, 0.1 ml of 0.9% sodium chloride solution was injected into bilateral Neiguan acupoints for group B, and: 0.1 ml puerarin injection was injected into bilateral Neiguan points for C. The rats in group C were sacrificed at the 8th minute of intravenous infusion of 0.9% sodium chloride solution, and those in groups B, T, and P were sacrificed at the 8th minute of intravenous infusion of bupivacaine, then the left ventricular myocardium of all rats were taken out and cardiomyocyte mitochondria were isolated, the structure of which was observed under the transmission electron microscope. The semi-quantitative analysis of mitochondrial structure was evaluated by Flameng classification system. The activity of mitochondrial adenosine triphosphate synthase (ATPase) was measured by ELISA. The content of adenosine triphosphate (ATP) was measured by colorimetric assay. The mitochondrial membrane potential (MMP) was detected by JC-1 fluorescence staining and colorimetry. The protein levels of myocardial mitochondrial peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) , nuclear respiratory factor 1 (NRF1) , and mitochondrial transcription factor A (mtTFA) were measured by Western blotting. Results Group C had lower Flameng score than did other three groups (P