Study On Cardiotoxicity Of Water-extract From Kusnezoff Monkshood In Vivo And In Vitro

Kusnezoff monkshood was a kind of aconitum, which was widely used as a Traditional Chinese Medicine. It had been used for 2000 years in China,and had pharmacology effects such as anti-inflammation and cancer, relieving pains. At the same time it was also very toxic, especially in cordis system.It could result in kinds of serious arrhythmia, dysfunction of cardiovascular system, and shock, even death. In recent years, there were several reports about the death caused by mistaking or processing of raw kusnezoff monkshood improperly in mainland and Hongkong. However, there were few reports about the toxic mechanism of the processing drugs of aconitum, especially studies in vitro. To evaluate the cardiotoxicity in vivo and in vitro, and to investigate the mechanism of it, we studied the toxicity effect of water-extract from kusnezoff monkshood on neonatal rat cardiac myocytes and cardiovasoiogy system of Beagle dogs.The primary cultured neonatal rat cardiac myocytes were randomly divided into five groups: three groups exposed to different concentration of water-extract from kusnezoff monkshood (10 mg raw drug/ml, 2 mg raw drug/ml, 0.4 mg raw drug/ml), positive control group (exposed to aconitine 10μg/ml) and negative control group(exposed to PBS buffer). The cardiac myocytes were exposed to aconitine at 5 days of culture, and the morphology and characteristic changes of the cells were examed at 24h and 48h after exposure, including the measurement concentration of malondialdehyde, the cytoactive by MTT assay and the apoptosis index by FCM. The results revealed that water-extract from kusnezoff monkshood at 10 mg raw drug/ml caused morphologic changes, decreased cytoactive, marked oxidative damage and cell apoptosis. In 2 mg raw drug/ml group only mild toxic changes existed, and there were few changes observed in 0.4 mg raw drug/ml group. We concluded the mechanism of toxic changes may be as the following: aconitine and analogs from water-extract from kusnezoff monkshood activated Ca²⁺ channel, inhibited L-type Ca²⁺ channel, which caused the electrophysiological changes of the cells; induced energy dysfunction and injured the cells directly through inhibiting Na⁺-K⁺-ATP enzyme and enzymes of chondrosome. Ca²⁺ overloading and aerobic dysbolism induced cell apoptosis, aggravated cell toxic action.6 Beagle dogs were given water-extract from kusnezoff monkshood 2.49 g raw drug/kg through gastric tube. The blood pressure(SBP/DBP/MBP) and leadâ…¡electrocardiography (heart rate, P/T/R waves and QRS/PR/QT intervals) were measured before lavage and at 30, 60, 90, 120, 180,240min after it. The results revealed no significant changes in BP and electrocardiography(P＞0.05) before and at the time points after lavage,The results from our laboratory showed that water-extract from kusnezoff monkshood was overt toxic only at the concentration of 10 mg mg raw drug/ml in vitro, and in Beagle dogs there were no significant cardiovasculary toxicity at 2.49 g raw drug/kg.