Investigation Of The Cardiac Toxicity Of Acori Tatarinowii Rhizoma And Mechanism From Apoptotic Pathway

Objective:Acori Tatarinowii Rhizoma?ATR?is a Chinese Medicine mostly used in the treatment of epilepsy,senile dementia,cardiovascular diseases and stroke,especially in curing cardiovascular diseases,it has the effect of removing dampness by regulating stomach,awakening consciousness and improving intelligence and dissipating phlegm for resuscitation.It has been concerning about the security issues of ATR with the long term administration and an in-depth research.Previous study in our laboratory indicated that ATR was definitely harmful to cardiomyocyte,but the mechanisms remain elusive.Accordingly,the Sprague Dawley?SD?rats were given ATR water solution with oral administration for thirty days and sixty days,we observed the cardiac toxicity of ATR and explored the mechanisms.Methods:The SD rats were given ATR water solution with oral administration for thirty days and sixty days,then,the rats were anesthesized and their hearts were removed to detect pathological changes of myocardium with HE staining and the apoptosis of cardiomyocyte by TUNEL method.We collected the blood from abdominal aorta aneurysm and determined the content of the aspartate aminotransferase?AST?,lactate dehydrogenase?LDH?,creatinine kinase?CK?,alpha-hydroxybutyrate dehydrogenase??-HBDH?in the serum,And the creatine kinase isoenzyme?CK-MB?,glycogen phosphylase isoenzyme?GPBB?and brain natriuretic peptide?BNP?in the serum measured by ELISA to explore the myocardial injury effect of ATR water solution on SD rats.We measured in SD rats according to the kit to determine calcium overload;Then,the protein expression levels of Bcl2?Bax?Cytc?Caspase3/8/9 and PGC-1?were detected by Western Blot to analyze the mechanism of the cardiac toxicity of ATR.Results:The results of HE staining indicated that the cardiomyocytes of groups with different dosage of ATR water solution manifest nuclear condensation,an orderly arrangement of myocardial fibers,a regular shape,and no inflammatory cell infiltration.There were 14.3%of rats in low dosage group manifested an abnormal increase of AST and CK enzyme activities,and an increase of CK-MB enzyme activities in all groups,and 12.5%in middle dose group and 16.7%in high dosage group showed an abnormal increase of GPBB,and no increase of LDH and BNP activities compared with control group;and the activity of Na⁺-K⁺-ATPase and Ca²⁺-Mg²⁺-ATPase in different dosage groups without reducing after a thirty days'oral administration of ATR water solution;The results of Western Blot showed that the ratio of Bax/Bcl2 decreased in all groups,and the expression of Cleaved-Caspase9 were up-regulated,but the protein expression level of Cleaved-Caspase3 and Caspase8 had no significant changes.The expression of PGC-1?did not decrease after the thirty days'oral administration of Acori Tatarinowii Rhizoma water solution;When the SD rats were given ATR water solution with oral administration for sixty days later,the myocardium of the middle dosage group showed partly dissolved and nuclear condensation in high dosage group,myocardium fibers arranged disorder and no inflammatory cell infiltration as well.The results of TUNEL staining revealed that there were few positive cells in the middle dose group,and increased notably in the high dosage group after sixty days'oral administration of Acori Tatarinowii water solution.after a sixty days'oral administration of ATR water solution,there was an abnormal increase of CK in low dosage group,the activity of GPBB of different dosage group presented a dose-dependent increase,while the activity of AST?LDH?CK-MB??-HBDH and BNP with no increase.but a abnormal decrease value in different dosage groups of activity of Na⁺-K⁺-ATPase?11.11%in low dose group?a sixth in middle dose group and an eight12.5%in high dose group?and all decrease activities of Ca²⁺-Mg²⁺-ATPase?P<0.05?,the ratio of the Bax/Bcl2 increased,the protein expression of Cleaved-Caspase3 and Cleaved-Caspase9 increased without exception,while the expression level of Caspase8 had no significant changes,the expression of Cytochrome C in cytoplasm were up-regulated,but a decreased in mitochondrial.The expression level of mitochondrial biogenesis protein of PGC-1?decreased.Conclusion:A long term administration of ATR water solution could induce the cardiac toxicity to SD rats,and the mechyanism may be related to the mitochondrial apoptosis of cardiomyocyte under the regulation of PGC-1?.