基于Cav1.2/CaM/CaMKⅡ通路探讨"稳心方"可溶性微针对缺血性心律失常大鼠的作用机制OA

Objective To investigate the mechanism of action of Wenxin Formula(稳心方,WXF)dissolvable microneedles(WXF-DMNs)applied via acupoint application in rats with ischemic arrhythmia(IA).Methods An IA model was established by ligating the left anterior descending coronary artery in 48 male SD rats,which were randomly divided into the following groups:sham-operated,model,positive drug(propranolol,5 mg·kg-1·d-1 by gavage),traditional powder application,blank matrix soluble microneedles,and WXF-DMNs high/medium/low-dose groups.Except for the positive drug group,all other groups received an equal volume of normal saline via gavage.All acupoint application interventions were administered at the Xinshu(BL 15)and Jueyinshu(BL 14)acupoints for 8–12 hours each time,for 3 days.Outcome measures included changes in Lead Ⅱ electrocardiogram(ECG);myocardial tissue histopa‑thology assessed by HE and Masson staining;serum B-type natriuretic peptide(BNP)concentration measured by enzyme-linked immu‑nosorbent assay(ELISA);the relative mRNA expression levels of Cav1.2,calmodulin(CaM),and Ca2+/calmodulin-dependent protein kinase Ⅱ(CaMKⅡ)in myocardial tissue determined by reverse transcription quantitative polymerase chain reaction(RT-qPCR);and the protein expression levels of Cav1.2,CaM,CaMKⅡ,and phosphorylated CaMKⅡ(p-CaMKⅡ)evaluated by Western blot(WB).Results Compared with the sham-operated group,the model group exhibited significant ST-segment elevation on ECG accompanied by marked arrhythmias,myocardial inflammatory infiltration and significant collagen fibrosis,and significantly elevated BNP levels(P<0.01).Furthermore,the model group showed significantly decreased Cav1.2 mRNA and protein expression(P<0.01),while the mRNA and protein expression of CaM and CaMKⅡ,as well as p-CaMKⅡ levels,were significantly increased(P<0.01).After interven‑tions,all treatment groups showed alleviation of ECG abnormalities,histopathological changes,and BNP levels.Among them,the posi‑tive drug group and the WXF-DMNs high-dose group demonstrated the most significant effects,upregulating Cav1.2 expression and downregulating the expression of CaM and CaMKⅡ,as well as p-CaMKⅡ levels(P<0.05 or P<0.01).Conclusion Acupoint application of WXF-DMNs alleviates IA by modulating the Cav1.2/CaM/CaMKⅡ signaling pathway,thereby reducing cardiomyocyte calcium over‑load and ameliorating structural damage.