Effects Of Propofol On Ca²⁺-ATPase Activity Of Sarcoplasmic Reticulum In Cardiac Hypertrophy Rats

Objective To investigate the effects of propofol on Ca²⁺-ATPase activity ofarcoplasmic reticulum and circulation in cardiac hypertrophy rats. To study the possiblemechainism of propofol on cardiac hypertrophy rats circulating.Methods Fifty SD rats were randomly allocated into normal control group （groupA,n=10） and model of myocardial hypertrophy group（n=40）.The myocardial hypertrophygroup were randomly divided into four groups with10rats each: model group （group B1）,30mg propofol group （group B2）,60mg propofol group （group B3） and intralipid group （groupB4）. Model of myocardial hypertrophy: forty rats were treated with norepinephrine （NE）1.5mg·kg-1intraperitoneally twice daily for15days. The group A, B2, B3and B4wereanesthetized with pentobarbital,arteria femoralis and femoral vein puncturing catheter,then connected to the monitor and the infusion pump.These groups were perfused withsaline,different doses of propofol and intralipid. MAP and HR of these rats were recordedbefore pretreatment with propofol （T₀）,after pretreatment with propofol1min（T₁）,3min（T₂）,5min（T3）,10min（T4）,20min（T5）,30min（T6）. All rats were sacrificed with deepanesthesia after infusion for30min and the parameters of the heart and ventricular weightwere determined. The morphological changes of myocardial tissue were observed with lightmicroscope, moreover calcium ion concentration in myocardial tissue and Ca²⁺-ATPaseactivity of sarcoplasmic reticulum were determined.Results1.The changes of MAP, HR of rats in group A, B2, B3each time point:（1） Theinfluence of propofol on the MAP of rats: There was no statistic significance among three groups at T₀（P＞0.05）.The MAP of three groups decreased with the infusion of propofol atT₁and T₂（P＜0.05）. At the subsequent time points, group A gradually returned to basalvalue （P＞0.05） and group B2increased gradually to be stable but was still below the basevalue （P＜0.05）.With the continuous infusion of propofol, group B3decreased gradually ateach time point and reached the lowest value at30min（P＜0.05）.Group B3was lower thanthe group B2at T3～T6time points（P＜0.01）.（2） The influence of propofol on the HR of rats:There was no statistic significance among three groups at T₀（P＞0.05）. The HR of threegroups decreased with the infusion of propofol at T₁and T₂time points （P＜0.05）. At thesubsequent time points, group A gradually returned to basal value （P＞0.05）and group B2increased gradually to be stable but was still below the base value （P＜0.05）.Group B3decreased gradually at each time point and reached the lowest value at30min（P＜0.05）.Group B3was lower than the group B2at T3～T6time points（P＜0.01）.2.The totalcalcium of myocardial tissue content: Compared with group A, calcium ion concentration ofeach subgroups were significantly higher（P＜0.05）, however there was no statisticsignificance among each subgroups of group B（P＞0.05）.3.Ca²⁺-ATPase activity of cardiacsarcoplasmic reticulum: Compared with group A, Ca²⁺-ATPase activity of each subgroupswas decreased（P＜0.05）. Among myocardial hypertrophy group: group B1and group B4were higher than group B2and group B3while group B2was higher than group B3（P＜0.05）.Conclusion1.Compared with the normal rats, the hemodynamic changes of propofol in cardiachypertrophy rats were more obvious.2. Propofol reduced the Ca²⁺-ATPase activity of myocardial sarcoplasmic reticulum incardiac hypertrophy rat.3. Inhibition of propofol on hemodynamic in cardiac hypertrophy rats may be related tothe Ca²⁺-ATPase activity.