Chinese medicinal formula Guanxin Shutong capsule protects the heart against oxidative stress and apoptosis induced by ischemic myocardial injury in rats

Abstract

Guanxin Shutong capsule (GXSTC) is a Chinese medicinal formula that has been used clinically for the treatment of chest pain, depression, palpitation and cardiovascular diseases in China for almost 10 years. The aim of the present study was to investigate the protective mechanisms against oxidative stress and apoptosis that GXSTC exhibits in the hearts of rats with myocardial ischemia (MI). Infarct size and the levels of marker enzymes, including serum creatine kinase-isoenzyme (CK-MB), lactate dehydrogenase (LDH) and glutamate oxaloacetic transaminase (GOT), as well as the levels of nitric oxide (NO) and NO synthase (NOS) in the heart were measured by biochemical analysis assays. Levels of the antioxidants superoxide dismutase (SOD), catalase (CATA), and glutathione (GSH), and the oxidative stress marker malondialdehyde (MDA), were also determined. Following a 6-week period of ischemia, myocardial apoptosis, as well as the protein and mRNA expression of NADPH oxidase, was evaluated. Myocardial NADPH oxidase activity was measured by protein expression of p47phox and gp91phox using western blot analysis and mRNA expression of p22phox, p47phox, p67phox and gp91phox using reverse transcription polymerase chain reaction. The results showed that daily oral treatment of the rats with GXSTC reduced infarct size, myocardial apoptosis, the levels of serum MDA, LDH, CK-MB and GOT and heart GOT, and increased the activities of total SOD, CATA, NOS and the levels of NO and GSH compared with those in vehicle-treated MI model rats. Administration of GXSTC for 6 weeks also reduced the mRNA expression of the NADPH oxidase subunits p47phox and gp91phox protein, as well as the expression of Bax and caspase-3 proteins. By contrast, Bcl-2 protein expression increased. In conclusion, the results demonstrate that GXSTC attenuates myocardial injury via antioxidative and antiapoptotic effects.

Keywords: Guanxin Shutong capsule; NADPH oxidase; myocardial infarction; oxidative stress.

Figure 1

Effect of GXSTC on the serum levels of (A) CATA, (B) MDA, (C) SOD and (D) GSH. Sham (sham-operated control; n=12), MI + vehicle (orally administered vehicle; n=12), MI + GXSTCH (orally administered 0.2 g/kg GXSTC; n=12) and MI + GXSTCL (orally administered 0.1 g/kg GXSTC; n=12). ^*P<0.05 and ^**P<0.01, vs. MI + vehicle. GXSTC, Guanxin Shutong capsule; CATA, catalase; MDA, malondialdehyde; SOD, superoxide dismutase; GSH, glutathione; MI, myocardial infarction.

Figure 2

Effect of GXSTC on (A) serum CK-MB (B) SGOT and (C) serum LDH. Sham (sham-operated control; n=12), MI + vehicle (orally administered vehicle; n=12), MI + GXSTCH (orally administered 0.2 g/kg GXSTC; n=12) and MI + GXSTCL (orally administered 0.1 g/kg GXSTC; n=12). ^*P<0.05 and ^**P<0.01, vs. MI + vehicle. GXSTC, Guanxin Shutong capsule; LDH, lactate dehydrogenase; CK-MB, creatine kinase-isoenzyme; SGOT, serum glutamate oxaloacetic transaminase; MI, myocardial infarction.

Figure 3

Effect of GXSTC on the levels of (A) SOD, (B) GOT, (C) NO and (D) NOS in the heart. Sham (sham-operated control; n=12), MI + vehicle (orally administered vehicle; n=12), MI + GXSTCH (orally administered 0.2 g/kg GXSTC; n=12) and MI + GXSTCL (orally administered 0.1 g/kg GXSTC; n=12). ^*P<0.05 and ^**P<0.01, vs. MI + vehicle. GXSTC, Guanxin Shutong capsule; SOD, superoxide dismutase; GOT, glutamate oxaloacetic transaminase; NO, nitric oxide; NOS, nitric oxide synthase; MI, myocardial infarction.

Figure 4

Effect of GXSTC on p22phox, p47phox, p67phox and gp91phox mRNA expression in the heart. (A) Bands correspond to p47phox, p22phox, p67phox, gp91phox and GAPDH. Results of (B) p22phox, (C) p47phox, (D) p67phox and (E) gp91phox were quantified by densitometry analysis of the bands from (A) and then normalized against GAPDH in the heart tissue. Sham (sham-operated control; n =12), MI + vehicle (orally administered vehicle; n=12), MI + GXSTCH (orally administered 0.2 g/kg GXSTC; n=12) and MI + GXSTCL (orally 0.1 g/kg administered GXSTC; n=12). ^*P<0.05 and ^**P<0.01, vs. MI + vehicle. GXSTC, Guanxin Shutong capsule; MI, myocardial infarction.

Figure 5

Effect of GXSTC on apoptosis-associated protein expression in all treated groups. (A) Bands correspond to Bcl-2, Bax, caspase-3 and GAPDH. Results of (B) Bax, (C) Bcl-2 and (D) caspase-3 were quantified by densitometry analysis of the bands from (A) and then normalized against GAPDH in the heart tissue. Results were obtained from three independent experiments performed in triplicate. ^*P<0.05 and ^**P<0.01, vs. MI + vehicle. GXSTC, Guanxin Shutong capsule; MI, myocardial infarction.

Figure 6

Effect of GXSTC on the NADPH oxidase subunits, p47phox and gp91phox, in heart tissue. (A) Bands correspond to p47phox, gp91phox and GAPDH. (B) gp91phox and (C) p47phox were quantified by densitometric analysis of the bands from (A) and then normalized against GAPDH protein. Results were obtained from three independent experiments performed in triplicate. ^*P<0.05 and ^**P<0.01, vs. MI + vehicle. GXSTC, Guanxin Shutong capsule; MI, myocardial infarction.