ABSTRACT
AIM: To study the effects of propofol on plasma membrane fluidity in PC12 cells and liposome,and its relevant mechanism. METHODS: Fluorescence depolarization method was used to measure values of fluorescence anisotropy, fluorescence polarization as well as microviscosity in PC12 cells and microviscosity in liposome continuously for 30 min. RESULTS: Propofol induced a significant decrease of fluorescence anisotropy, fluorescence polarization as well as microviscosity in PC12 cells, particularly in the first 5 min. After 5 min, the values of anisotropy were remained lower levels. Although propofol at concentration of 1 mg?L -1 had no effects on microviscosity in liposome, porpofol at concentration of 10 mg?L -1 and 100 mg?L -1 significantly decreased microviscosity in liposome. CONCLUTION: Propofol can significantly increase membrane fluidity in PC12 cells and liposome in a concertration dependent manner, and the anesthetic effect of propofol may be resulted from changes of membrane fluidity and structure of neurocyte.
ABSTRACT
Objective To investigate the sinusoidal endothelia) cell (SEC) apoptosis induced by hepatic ischemia-reperfusion (I/R) and the effect of propofol on the hepatic cell apoptosis in vivo. Methods For hepatic I/R study we utilized a rat model of 70% liver ischemia according to Kohli, et al . Twenty-four male SD rats weighing 250-350 g were randomly assigned to 3 equal groups of eight animals : group A was subjected to 30 min of liver ischemia followed by 6 h of reperfusion and normal saline was infused iv at the onset of reperfusion, at a rate 10 ml ? kg-1 ? h -1 for 60 min; group B was subjected to the same J/ R as in group A but instead of NS propofol 20 mg " kg was given iv followed by continuous infusion of 0.5% propofol at 50 mg? kg-1 ? h-1 for 60 min; group C underwent sham operation followed by intravenous NS infusion at 10 ml kg h for 60 min. Blood samples and liver biopsies were obtained at the end of 6h of reperfusion, for determination of plasma alanine aminotransferase (ALT) activity and hepatic malondialdehyde (MDA) content, apoptosis and microscopic examination (light and electron microscopy) . Apoptosis was determined both qualitatively and quantitatively by DNA laddering and TUNEL methods. Results In group A there was a significant increase in apoptotic hepatocytes and SEC after I/R as compared with group C ( P