Glycyrrhetinic Acid protects the heart from ischemia/reperfusion injury by attenuating the susceptibility and incidence of fatal ventricular arrhythmia during the reperfusion period in the rat hearts.

BACKGROUND/AIMS: Licorice has been used to treat many diseases, including palpitations, in both Eastern and Western societies for thousands of years. It has been reported that glycyrrhetinic acid (GA), an aglycone saponin extracted from licorice root, exerts protective effects on the cardiovascular system, limits infarct sizes and protects against the development of arrhythmia. However, the mechanisms underlying the effects of glycyrrhetinic acid on the cardiovascular system remain poorly understood. This study aimed to determine the mechanisms underlying the protective effects of GA against lethal cardiac arrhythmias induced via ischemia-reperfusion in rat hearts, and to examine its electropharmacological properties. MATERIALS AND METHODS: Anesthetized rats were divided into control (CTL), GA5, GA10, and GA20 groups. GA was administered intravenously 15 min before the occlusion of the left anterior descending coronary artery, at dosages of 5, 10 and 20 mg/kg, respectively. Single ventricular myocytes were isolated using enzymolysis. The whole-cell patch clamp technique was utilized to record Ica, L, Ito and action potentials (APs). RESULTS: During reperfusion, the incidence of ventricular fibrillation (VF) was decreased in each of the groups compared with the CTL group (p<0.05). The ventricular tachycardia (VT)/VF score was significantly decreased in the GA20 group. Action potential durations (APDs) were prolonged by GA; both L-type calcium current (Ica-L) and transient outward potassium current (Ito) were blocked in a concentration-dependent manner by GA. CONCLUSION: These results suggest that GA attenuates both the susceptibility to and the incidence of fatal ventricular arrhythmia during reperfusion in rat hearts via the prolongation of the APD and the inhibition of both Ica-L and Ito. GA appears to be a promising antiarrhythmic agent in the setting of ischemia/reperfusion.

Shenfu Injection suppresses inflammation by targeting haptoglobin and pentraxin 3 in rats with chronic ischemic heart failure.

OBJECTIVE: To investigate the regulatory effects of Shenfu Injection (SFI, ) on hemodynamic parameters and serum proteins in rats with post-infarction chronic heart failure (CHF). METHODS: Forty-five healthy Wistar rats were randomized into three groups: sham, heart failure (model) and SFI group. The CHF was induced by left coronary artery ligation. Seven days after the surgical operation, animals in the sham group and the model group received saline (6.2 mL/kg/d), while animals in the SFI group received SFI (6.2 mL/kg d) intraperitoneally. Four weeks later, cardiac hemodynamic parameters were measured via the carotid route. The expression of serum proteins was analyzed by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS). RESULTS: Recording of hemodynamic parameters showed that left ventricular systolic pressure (LVSP), maximum rate of left ventricular pressure (+dp/dtmax) rise, and maximum rate of left ventricular pressure (-dp/dtmax) decrease, while the left ventricular end diastolic pressure (LVEDP) rose in the model group compared to those in the sham group (P <0.05). The results of the MALDI-TOF MS indicated that haptoglobin (HP), pentraxin 3 (PTX3) and alpha-1-antitrypsin were up-regulated, while serum albumin and 40S ribosomal protein were down-regulated in the model group (P <0.05). Compared with the model group, LVSP, +dp/dtmax and -dp/dtmax were higher, while LVEDP was lower in the SFI group (P<0.05). Expression levels of HP and PTX3 were lower than in the model group (P<0.05). CONCLUSION: SFI could improve hemodynamic function and decrease inflammatory reactions in the pathophysiology of CHF. The serum proteins HP and PTX3 could be potential biomarkers for chronic ischemic heart failure, and they could also be the serum protein targets of SFI.

Self-assembly of renal cells into engineered renal tissues in collagen/Matrigel scaffold in vitro.

To tissue engineer a kidney is a formidable task because of the complex cell composition and structures in the kidney. This study reconstructed renal tissues using mixed renal cells in collagen/Matrigel® scaffolds in vitro. Neonatal rat renal cells were seeded in collagen I supplemented with Matrigel in a casting mold that could exert static stretch when the renal constructs contracted. During in vitro culture, the renal constructs were observed under microscope and analyzed by histological and immunofluorescent examinations. Results showed that the mixed renal cells reconstituted renal tubular and glomeruli-like structures with different appearances at varying developmental stages. Tubular structures were formed by CK18-positive cells with similar appearances lining the surrounding hollow centres. The glomeruli-like structures were tufts of cell aggregates containing Flk-1-positive cells. These results show that neonatal rat renal cells self-assembled into engineered renal tissues containing both tubules and glomeruli-like structures when cultured in 3D collagen/Matrigel scaffold in vitro.

Effect of matrine on human ether à go-go related gene (HERG) channels expressed in Chinese hamster ovary cells.

OBJECTIVE: To observe the effect of matrine on human ether à go-go related gene (HERG) potassium channels expressed in Chinese hamster ovary (CHO) cells and investigate whether HERG channel is a new target of the pharmacological effect of matrine on arrhythmia and tumor METHODS: HERG channel potassium current in CHO cell was recorded using whole-cell patch-clamp technique, and the influence of matrine on the current was explored. RESULTS: Matrine inhibited HERG potassium current in a dose-dependent manner, and the 50% inhibitory concentration (IC IC(50)) was 411±23 µmol/L. Matrine had no significant effect on the activation kinetics, and mainly blocked HERG channels in their closed state. CONCLUSIONS: The blocking effect of matrine on HERG channels might be one of the mechanisms against arrythmias and tumors. Unlike most other blockers exerting blocking effect at the intracellular sites by entering the cell with the opening of HERG channel, matrine blocked HERG channels at the extracellular sites.