Protective effects of Shexiang Tongxin Dropping Pill on pituitrin‑induced acute myocardial ischemia in rats.

Shexiang Tongxin Dropping Pill (STP) is an established traditional Chinese medicine that is widely used for the treatment of ischemic heart disease (IHD), although its mechanisms remain unclear. The present study investigated the protective effects of STP following pituitrin (PTT)‑induced myocardial ischemia in rats. ST‑segment elevation, blood rheology, and the serum levels of creatine kinase‑MB (CK‑MB) and lactate dehydrogenase (LDH) were measured. Following heart excision, histological analysis using hematoxylin and eosin and terminal deoxynucleotidyl transferase dUTP nick end labeling were performed. The mRNA expression levels of B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X protein (Bax) were determined using reverse transcription‑quantitative polymerase chain reaction, and their protein expression was detected using immunohistochemistry. The results demonstrated that STP treatment protected against ST elevation, lowered whole blood viscosity, and reduced the serum levels of CK‑MB and LDH following acute myocardial ischemia. In addition, STP treatment restored the histopathological change following PTT‑induced myocardial ischemia, and resulted in downregulated expression of Bax and upregulated expression of Bcl‑2 in myocardial tissue. The present study demonstrates the cardioprotective ability of STP in a rat model of myocardial ischemic injury, which may be attributed to its anti‑apoptotic properties. The cardioprotective properties of STP require further investigation to determine whether it may be used for the clinical treatment of IHDs.