The change of ryanodine receptor 2 expression in rats with septic shock / 中国小儿急救医学

ABSTRACT

Objective To investigate the changes of myocardial systolic and diastolic function and the expression of ryanodine receport 2 (RyR2)during different degree of myocardial dysfunction in septic shock rats.Methods We used random number method to divide 250 to 300g male Wistar rats into septic shock group and the control group which were divided into 4 subgroups at different time intervals of 0h,2h,4h,6h with six rats in each subgroup.The rat model of septic shock was established by intravenous dosing of LPS.When mean arterial pressure reduced by 25% to 30% from the basic value,a model of septic shock was established.We monitored the mean arterial pressure through femoral arterial catheterization and the left ventricular end-diastolic pressure,maximum rate of left ventricular systolic pressure rise(+dp/dt max) and maximum rate of left ventricular diastolic pressure drop(-dp/dt max)through carotid arterial catheterization.The pathological changes of myocardial tissue were observed via the pathological sections.The changes of RyR2 expression and the phosphorylation of RyR2 were detected via immunohistochemistry.The change of RyR2 gene expression was detected via PCR.Results In septic shock group,myocardial structure disturbance was worsen,myocardial tissue was ruptured,and myocardial cells and nucleus was disrupted.Myocardial dysfunction was gradually aggravated with the extension of time.The immunohistochemical results showed that the expression of RyR2 protein in septic shock group was higher than that in the control group(P<0.01), while the expression at 0h in septic shock group was the highest.As the extension of shock time,the myocardial function of rats decreased,the expression of RyR2 gradually declined in protein level,but the phosphorylation of RyR2 rised.The PCR results showed that the mRNA expression of RyR2 in septic shock group was higher than that in the control group(P<0.01), while the mRNA expression in septic shock group at early stage was the highest.As the extension of shock time,the mRNA expression of RyR2 gradually declined.Conclusion As the Ca2+ channel in the heart,the expression of RyR2 and the phosphorylation of RyR2 might be highly associated with the severity level of myocardial dysfunction under septic shock.