Effect of Yiqi Huoxue Lishui Recipe on calcium transport and endoplasmic reticulum stress in cardiomyocytes f rats with heart failure

Objective To investigate the effects of Yiqi Huoxue Lishui Recipe on calcium transport, endoplasmic reticulum stress apoptosis and the expressions of angiotensin Ⅱ (Ang Ⅱ) and transforming growth factor-β₁ (TGF-β₁) in cardiomyocytes of heart failure (HF) rats.

Methods Ten healthy rats were set as Sham group, and another 45 successfully modeled rats were divided into HF group, low intervention group, medium intervention group, high intervention group and western medicine group, with 9 rats in each group. The low intervention group, middle intervention group and high intervention group were gavaged with 2.6, 5.2 and 10.4 g/(kg·d) of Yiqi Huoxue Lishui Recipe, the western medicine group was gavaged with 10 mg/(kg·d) trimetazidine, and the Sham and HF groups were gavaged with the same volume of 0.9% NaCl solution, respectively. HE staining and electron microscopy were used to observe the pathological morphology of myocardial tissue. Bradford dye binding method was used to analyze the calcium intake in the myocardial sarcoplasmic reticulum. The apoptosis of cardiomyocytes in each group was detected by Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL). Western blotting was used to detect the expressions of endoplasmic reticulum stress-related proteinsB cell lymphoma/leukemia-2 (Bcl-2), Bcl-2 associated X protein (Bax), caspase-3 protein (Caspase3)and calcium transport-related proteinscalcium/calmodulin-dependent protein kinase Ⅱ (CAMK Ⅱ), ryanodine receptor (RyR2) and sarcoplasmic reticulum Ca²⁺ ATPase (SERCA2a); the positive expression rates of TGF-β₁ and Ang Ⅱ in myocardial tissue were detected by immunohistochemistry.

Results The calcium uptake rates of rats in the Sham group, HF group, low intervention group, middle intervention group, high intervention group and western medicine group were (19.63±5.63) μmol/(min·mg), (10.25±4.11) μmol/(min·mg), (13.70±5.12) μmol/(min·mg), (14.08±4.80) μmol/(min·mg), (16.91±5.03) μmol/(min·mg), (16.65±5.10) μmol/(min·mg), respectively, there were differences among different groups (F=3.946, P=0.004). The apoptosis rates of cardiomyocytes in the Sham group, HF group, low intervention group, medium intervention group, high intervention group and western medicine group were (7.52±2.01)%, (30.63±6.58)%, (19.14±5.03)%, (18.41±5.21)%, (13.61±3.65)% and (13.17±4.11)%, respectively, there were differences among different groups (F=28.900, P < 0.001); compared with the Sham group, Bcl-2 and SERCA2a levels in the HF group in myocardial tissue of rats were decreased, and Bax, Caspase3, CaMK Ⅱ, RyR2, TGF-β₁ and Ang Ⅱ expression were increased (P < 0.05). Compared with the HF group, expressions of Bcl-2 and SERCA2a were increased in the low, medium and high intervention groups and western medicine group, Bax, Caspase3, CaMK Ⅱ, RyR2, TGF-β₁ and Ang Ⅱ were all decreased (P < 0.05). There were no significant differences in the low intervention group in above eight indicators compared with the medium intervention group (P>0.05). Compared with the medium intervention group, the high intervention group showed significant differences in above indexes (P < 0.05), but there was no significant differences compared with the western medicine group in above indexes (P>0.05).

Conclusion Yiqi Huoxue Lishui Formula can improve calcium transport in heart failure rats, and reduce myocardial apoptosis by inhibiting endoplasmic reticulum stress in a concentration-dependent manner. The mechanism may be related to the inhibition of TGF-β₁ and Ang Ⅱ expression.