Aconitum Alkaloids Myocardial Toxicity

Objective: To investigate protective effects and mechanism of liquiritin, glycyrrhizic acid, glycyrrhetic acid and ginsenoside Rg1, Rb1, Re on primary cultured cardiomyocytes of newborn rats injured by aconitine.Methods: Neonatal rat ventricular myocytes were isolated and subcultured on plates. When they grew to a single layer or partly mixed together, we challenged them with different concentration aconitine(AC), AC plus liquiritin, AC plus ginsenoside Rg1, AC plus ginsenoside Rb1, AC plus ginsenoside Re. then cell survival rate was measured by MTT assay and the completenes of myocardial cell membrane was observed by the activity of lactate dehydrogenase (LDH) in the culture medium. Total RNA was extracted from these cells by the Trizol Reagent method. The expression of ion channel SCN5A, Kv4.3 and Cav1.2 mRNA was examined by reverse transcriptase -polymerase chain reaction ,the density of these bands were semi-quantified.Results: 1. The method we adopt could get free and living cardiocytes from neonatal rats and its purity above 90%. 2. There were no changes for survival rate between each concerntration from 4h to 24h. 3. LDH of cultured medium in cardioctyes exposed by AC increased compared with control (P<0.01), and with the increase of AC concentration, LDH release increased significantly (P<0.01)within 0.1-0.3mmol/L. The liquiritin, glycyrrhizic acid and ginsenoside Rg1, Rb1 and Re can decrease the LDH release reduced by AC markedly, while glycyrrhetic acid intensify the release of AC from cell interior. 4. There were significant increases in abundance of SCN5A ,Cav1.2 mRNAs and significant decreases in that of Kv4.3 mRNA in aconitine group compared to the control(P<0.01). The liquiritin and ginsenoside Rg1, Rb1 and Re all could reverse the SCN5A, Cav1.2, Kv4.3 mRNA abnormal expression induced by aconitine.Conclusion: 1. The methods of isolation and culture of neonatal rat cardiocytes. was successful. 2. AC (5 20 40 80 160 320 640 1280μmol/L)couldn't infect the survival rate of myocytes within 24h. 3. The liquiritin, glycyrrhizic acid and ginsenoside Rg1, Rb1 and Re can resist the toxicity of AC results in the biology membrane damaged. 4.The liquiritin, and ginsenoside Rg1, Rb1 and Re which work together with aconitine can alleviate the side effects and boost up the therapeutic effects of aconitine. The action mechanism might be linked with that the liquiritin and ginsenoside Rg1 Rb1 and Re could suppress abnormal expression of ion channel genes SCN5A , Cav1.2, Kv4.3 mRNA in neonate rat cardiocytes induced by aconitine.