To study the protective effect of shexiang tongxin dropping pills (STDP) on anoxia-reoxygenation injury in H9c2 cardiomyocytes.

A model of myocardial anoxia-reoxygenation was established and the H9c2 cardiomyocytes were divided into 5 groups: a control group (with normal H9c2 cardiomyocytes), a model group, a STDP group (given 50 mg / L STDP 40 min before reoxygenation), a 3-methyladenine (3-MA) group (given 5 mmol / L 3-MA 40 min before reoxygenation), and a STDP + 3-MA group (given 50 mg / L STDP + 5 mmol / L 3-MA 40 min before reoxygenation). The cell survival rate was detected by cell counting kit-8, and the levels of lactate dehydrogenase (LDH), malonaldehyde, and creatine kinase were compared among the five groups. The apoptosis rate of cardiomyocytes was detected by flow cytometry. The messenger RNA (mRNA) expression levels of Beclin-1 and Atg5 were examined by real-time fluorescent quantitative PCR. The protein expression levels of LC3Ⅱ / LC3Ⅰ, hypoxia-inducible factor-1alpha (HIF-1α), Bcl-2 / adenovirus E1B 19 kDa-interacting protein 3 (BNIP3), Beclin-1, and Atg5 were detected by Western-blotting.

The cell survival rate was significantly different among the five groups (F = 85.893, P = 0.028), and it was much higher in the STDP group than in the model group, 3-MA group and STDP + 3-MA group [(90 ± 7)%, (63 ± 5)%, (80 ± 5)%, (81 ± 6)%; all P < 0.05]. The LDH, malonaldehyde, creatine kinase, apoptosis rate, Beclin-1 mRNA, Atg5 mRNA, LC3Ⅱ / LC3Ⅰ protein, HIF-1α protein, BNIP3 protein, and Beclin-1 protein were significantly different among the five groups (F = 78.381, 23.519, 48.376, 22.726, 6.315, 5.294, 75.219, 116.546, 21.125, 39.724, 65.247; all P < 0.05). In the STDP group, the levels of LDH [(92 ± 6), (194 ± 13), (195 ± 11), (192 ± 10) μmol / L], malonaldehyde [(12.5 ± 0.7), (17.2 ± 1.2), (18.5 ± 1.6), (17.9 ± 1.0) μmol / L], and creatine kinase [(19.9 ± 1.0), (34.3 ± 2.2), (35.3 ± 2.2), (34.8 ± 2.5) μmol / L] and the apoptosis rate of cardiomyocytes [(5.8 ± 0.8)%, (8.8 ± 0.9)%, (7.6 ± 0.7)%, (7.3 ± 0.5)%] were much lower than those in the model group, 3-MA group and STDP + 3-MA group, and the HIF-1α protein level was much higher (all P < 0.05); meanwhile, the levels of Beclin-1 mRNA, Atg5 mRNA, LC3Ⅱ / LC3Ⅰ protein, BNIP3 protein, Beclin-1 protein, and Atg5 protein were much lower than those in the model group, but were much higher than those in the 3-MA group and STDP + 3-MA group (all P < 0.05).

The STDP can protect cardiomyocytes from anoxia-reoxygenation injury by regulating the HIF-1α / BNIP3 signaling pathway.