Study On Effect Of Electrocardio Conduction By Doxorubicin Liposome Combined Cardiac Radiofrequency Ablation In Rabbits

Radiofrequency ablation is treatment approaches of arrhythmia,but it is also a problem needed to resolve because of electric conduction return to result in the long-term recurrence.The purpose of this study was to establish a novel animal model of left auricle ablation in rabbit by means of cardiac radiofrequency ablation and electrophysiological pacing and mapping technology.Otherwise,doxorubicin hydrochloride liposome can be used to further inhibit the activity of residual myocardial cell to reduce residual conduction gaps and hinder recovery of electrical conduction.The effects of electrocardio conduction by doxorubicin hydrochloride liposome combined cardiac radiofrequency ablation in rabbit are studied.We established an accurate,rapid and high-performance liquid chromatography(HPLC)method to detect the concentration of DOX.This topic used the method of ammonium sulfate gradient to prepare liposomes and characterization analysis.Eventually,we got the liposomes of uniform stability and the encapsulation efficiency was 99.8%.In addition,we established an accurate and rapid fluorometric analysis method to detect the concentration of IR-775 and adopted the thin-film hydration method to prepare IR-775 liposomes.The encapsulation efficiency of IR-775 liposome was 89.1%.We established a novel animal model of left auricle ablation in rabbit by means of radiofrequency ablation operation.Under the condition of ablation(parameter settings:P=15 W,T=55℃,t=15 s),we carry out linear circumferential ablation surgery of left auricle in rabbit by means of radiofrequency ablation instrument.In the left auricle ablation loop,pacemaker instrument gave the high frequency stimulation.And BL-420 biological signal collection system detected the electrical conduction in the left auricle.Finally,we found the potential of ablation loop inside was disappear after postoperative determination,but potential conduction have been recovery after 48 h in postoperative.However,we injected 5 mg of doxorubicin liposomes in postoperative,that showed potential conduction has not been recovery after 48 h.Therefore,we could draw a conclusion of drug group can delay the recovery of ablation potential after 48 h.Combining with biopsy pathology,we found that local myocardial tissue has a certain degree of damage,showed that myocardial tissue injury may be have certain influence on electrical conduction.We established a good specificity,high sensitivity fluorescence analysis method of determination doxorubicin hydrochloride in rabbit plasma.Compared with the free of doxorubicin(5 mg),the AUC0→24 h of doxorubicin hydrochloride liposomes has increased 3.8 times higher than doxorubicin hydrochloride,so the bioavailability of doxorubicin hydrochloride liposomes were significantly improved.The rabbits were intravenous administrated by fluorescent material IR-775 after left auricle ablation surgery.Compared with IR-775 group,IR-775 liposome has the stronger fluorescence intensity in heart tissue,which is 5.9 times higher than IR-775.Therefore,in novel animal model of left auricle ablation in rabbit,doxorubicin hydrochloride liposome targeting heart come from inflammation effect after ablation.