Effects of Sasanquasaponin on Ischemia and Reperfusion Injury in Mouse Hearts

Abstract

Abstract. We investigated effects of sasanquasaponin (SQS), a traditional Chinese herb's effective component, on ischemia and reperfusion injury in mouse hearts and the possible role of intracellular Cl -homeostasis on SQS's protective effects during ischemia and reperfusion. An in vivo experimental ischemia model was made in mice (weight 27 -45 g) using ligation of left anterior descending coronary artery, and in vitro models were made in perfused hearts by stopping flow or in isolated ventricular myocytes by hypoxia. The in vivo results showed that SQS inhibited cardiac arrhythmias during ischemia and reperfusion. Incidence of arrhythmias during ischemia and reperfusion, including ventricular premature beats and ventricular fibrillation, was significantly decreased in the SQS-pretreated group (P<0.05). Results in perfused hearts showed that SQS suppressed the arrhythmias, prevented against ischemia-induced decrease in contract force and promoted the force recovery from reperfusion. ] i during ischemia and reperfusion (P<0.05). Our results showed that SQS protected against ischemia / reperfusion-induced cardiac injury in mouse hearts and that modulation of intracellular Cl -homeostasis by SQS would play a role in its anti-arrhythmia effects during ischemia and reperfusion.

Sasanquasaponin promotes cellular chloride efflux and elicits cardioprotection via the PKCε pathway

“…Previous studies by our group showed that SQS effectively protected against myocardial injury in an isoproterenol-induced rat model of ischemia in vivo and in a hypoxia and reoxygenation model in Langendorff-perfused rat hearts in vitro (8,22,23). Another previous study by our group revealed that SQS exerts its cardioprotective effects by suppressing intracellular Cl -accumulation induced by sI/R (9).…”

“…The neonatal primary rat cardiomyocytes were divided into various experimental groups as follows: i) In the control group, cardiomyocytes were incubated under normal conditions for an additional 24 h; ii) in the sI/R group, cardiomyocytes were subjected to anoxia by incubating them in fresh anoxic medium [0.9 mM NaH 2 PO 4 , 6.0 mM NaHCO 3 , 1.8 mM CaCl 2 , 1.2 mM MgSO 4 , 40 mM sodium lactate, 20 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), 98.5 mM NaCl, 10.0 mM KCl, pH 6.8; Sigma-Aldrich] at 37˚C in a chamber containing 95% N 2 and 5% CO 2 for 3 h. Subsequently, the medium was replaced with re-oxygenation medium (129.5 mM NaCl, 5.0 mM KCl, 0.9 mM NaH 2 PO 4 , 20 mM NaHCO 3 , 1.8 mM CaCl 2 , 1.2 mM MgSO 4 , 5.5 mM glucose, 20 mM HEPES, pH 7.4; Sigma-Aldrich) and the cells were incubated at 37˚C in an atmosphere of 95% air and 5% CO 2 for 2 h; iii) In the SQS+sI/R group, cells were pre-treated with SQS at 10 µM for 24 h prior to sI/R; iv) In the SQS+εV1-2+sI/R group, cells were pre-treated with εV1-2 (1 µM) and SQS (10 µM) for 24 h prior to sI/R. The doses of SQS and εV1-2 used were selected on the basis of a preliminary study by our group and previous reports (8,18,19).…”

“…The measurement of [Cl -] i was performed according to the method described in a previous study by our group with minor modifications (8). Briefly, after the indicated treatments, cardiomyocytes were washed twice with Cl --free solution (NaCl was replaced by an equimolar amount of d-glucuronic acid, MgCl 2 by MgSO 4 and KCl by potassium gluconate), and incubated with 10 mM N-(ethoxycarbonylmethyl)-6-methoxyquinolinium (MQAE; Thermo Fisher Scientific, Inc.) in the dark for 20 min at 37˚C.…”

“…Sasanquasaponin (SQS) is an active component of Camellia oleifera Abel, which is used in Traditional Chinese Medicine. SQS is a triterpenoid with structural similarity to certain ginseng saponins (6,7), and is known to exert potent cardioprotective effects against I/R injury (8). A previous study by our group indicated that these beneficial effects of SQS may be attributed to the inhibition of I/R-induced elevation of [Cl -] i (9); however, the intracellular signal transduction mechanisms underlying these effects have yet to be elucidated.…”

Triterpenoid Saponins from the Genus Camellia

“…Sasanquasaponin (37) inhibited ischemic/reperfusion-induced cardiac arrhythmias by modulating intracellular Cl À homeostasis in mouse hearts [48]. Saponin 37 protected cardiomyocytes against oxidative stress induced by anoxia-reoxygenation by attenuating reactive oxygen species generation and increasing activities of endogenous antioxidants [49].…”