| Aim It is aimed to observe manifestations and feature of cardiotoxicity in acute toxicity and chronic toxicity of Radix Aconiti Lateralis Preparata (Fuzi) respectively, and to study the related mechanism of cardiotoxicity, for the purpose of providing scientific basis for safe and rational use of Fuzi in clinic.Methods1. According to the international ICH standards, the medium lethal dose (LD50) tests of the ethanol extracts of Hei-Shun Pian (HS), Bai-Fu-Pian (BF), and Ni-Fuzi (NF) and the maximum tolerated dose(MTD) tests of aqueous extracts of the three slices were carried out on mice by gavage under the IVC experimental surrounding; meanwhile, the acute toxicity tests for the six extracts were also conducted on rats to observe cardiac toxicity.2. According to the international ICH standards, the three-month chronic toxicity test of ethanol extract derived from NF were conducted on rats under IVC surrounding to study manifestations and feature of chronic cardiotoxicity of Fuzi.3. To explore the potential mechanism of Fuzi on cardiac toxicity, the primary cardiomyocytes were cultured in vitro and then exposed to medium containing aconitine with different concentrations. Morphologic changes were observed and parameters concerning cell membrane, internal environment or energy metabolism were detected.Results1.The LD50values of ethanol extract of HS for mice intragastric administration was49.853g crude drug/kg with95%confidential interval about45.804～54.636g crude drug/kg. The LD50of ethanol extract of BF was42.550g crude drug/kg and its95%confidential interval was38.221-47.828g crude drug/kg. The LD50of ethanol extract of NF for mice intragastric administration is22.168g crude drug/kg and its95%confidential interval was21.043～23.513g crude drug/kg. The MTD of water extracts of HS, BF, NF for mice intragastric administration were21.273,25.597,60.932g/kg, equal to48.80,59.00,92.80g crude drug/kg, respectively. When ethanol extracts of HS, BF, NF were administrated to rats at doses of5.08,6.06, and4.56g/kg, severe toxic manifestations and even death were appeared in some rats; however, the three water extracts didn’t induce toxic reactions and death on rats with oral doses of21.27,25.60,30.48g/kg respectively. Acute toxic syndromes on rats and mice focused on neurotoxicity, cardiotoxicity and the digestive system toxicity. The acute cardiotoxicity of Fuzi features as flollows:initially fast heart rate and precordial beat, arrhythmia, hot body, flush skin, tail and foot pad were observed, gradually the body tended cold with pale appearance or even cyanochroia on lips, claws, tail,ears and foot of pads, accompanied with weak beat on precordium and slow heart rate before death. The serum CK level and enlarged heart coefficient could be occurred in some rats.2The three-month chronic toxic test on rats of ethanol extract from NF showed that no obvious toxic syndromes were observed during the whole experiments except slight accelerated precordial beat and arrhythmia during the initial period. However, the24h-food intake of male rats deCREAsed and the MI, MID levels in blood inCREAsed. Besides, the organ morphologic examination showed injuries in heart tissue, manifesting as patchy or focal necrosis or dissolved, chronic inflammatory cell infiltration and fibrous connective tissue proliferation. For some rats, cloudy swelling, mild degeneration and a small amount of transparent type were observed in renal bubular epithelial cells in kidney.3.The minimum toxic dosage of aconitine on cardiomyocyte was0.2%. When respectively exposed the mediums containing aconitine0.2%,0.36%,0.63%,1.13%,2%for30minutes, it could induce cell beat suppression, deformation, take-off the wall, pyknosis and death. Under the electronic microscope, severe celluar toxicities were observed as cavity in the cytoplasm, swelling of mitochondria and rough endoplasmic reticulum and even ridge breakage of mitochondria as the concentration of aconitine was inCREAsed, followed by nuclear morphological abnormaliites, chromatin boundary trace, incomplete cell membrane. In the largest dosage, cell debrises, pyknosis, lots of cavity in the cytoplasm could be seen without mitochondria and rough endoplasmic reticulum. Aconitine induced LDH leakage inCREAsed, ACP overactivity, glycogen deCREAse, MDA inCREAse, intercellular K+deCREAse and Ca2+inCREAse.Conclusions1The acute cardiotoxicity of Fuzi features are as flollows:initially fast heart rate and precordial beat, arrhythmia, hot body, flush skin, tail and foot pad were observed, gradually the body tended cold with pale appearance or even cyanochroia on lips, claws, tail,ears and foot of pads, accompanied with weak beat on precordium and slow heart rate before death. The serum CK level and enlarged heart coefficient could be occurred in some rats.2. The chronic cardiotoxicity of Fuzi features are as follows:slight accelerated precordial beat and arrhythmia during the initial period. However, the24h-food intake of male rats deCREAsed and the MI, MID levels in blood inCREAsed. Besides, the organ morphologic examination showed injuries in heart tissue, manifesting as patchy or focal necrosis or dissolved, chronic inflammatory cell infiltration and fibrous connective tissue proliferation.3. Aconitine is the major toxic ingredient of Fuzi for its cardiotoxicity. The potential mechanism of cardiotoxicity is related to damage morphology,cell organelles, and cell membrane, induce oxidative damage, disturb internal environment and energy metabolism. |
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