RESUMO
The objectives of this study were to prepare polysaccharide modified compound liposomes loaded with paclitaxel (PTX) and doxorubicin (DOX) and characterize their phyisicochemical properties,stability and in vitro release profiles.Both PTX-DOX-Lipo and N-lauryl-O-glycol chitosan (LGC) modified liposomes (PTX-DOX-Lipo-LGC) were successfully prepared,and the morphology of the liposomes was observed by transmission electron microscope (TEM),and particle size and zeta potential were analyzed by dynamic light scattering (DLS).pH and osmotic pressure were also determined.The drug loading and encapsulation efficiency,stability and in vitro release were assayed using high-performance liquid phase.Both PTX-DOX-Lipo and PTX-DOX-Lipo-LGC exhibited spherical shape with smooth surface.The average diameter was about 150 nm.pH value and osmotic pressure were in the range of 5.3-6.1 and 820-870 mOsm/kg,respectively.Both PTX and DOX could be encapsulated in liposomes with high encapsulation efficiency (greater than 90％).Compared with PTX-DOX-Lipo,PTX-DOX-Lipo-LGC exhibited lower leakage,higher stability in serum and more sustained release profiles.Moreover,a quicker release rate was observed in pH 5.8 PBS compared with pH 7.4 PBS.PTX-DOX-Lipo-LGC with high drug loading,good stability and sustained drug release profiles has a wide prospect in future clinical application.
RESUMO
Objective To investigate the correlation of Bax and apoptosis in enterocytes of neonatal rats with necrotizing enterocolitis (NEC).Methods Forty-eight neonatal rats (1 day) were randomly divided into control group (n =24) and NEC model group (n =24) by use of odd and even.The rats in control group were maternal breast-fed.The rats in NEC model group were separated from their mothers.To be given formula feeding,cold exposure after hypoxic-reoxygenation treatment.The intestinal tissue located at the boundary of ileum and caecum of two groups were gained on the 24 h,48 h and 72 h with which that all rats were sacrificed by cutting neck.Section of intestinal tissue were stained with immunohistochemistry to detect the expression of Bax and were stained with TdT mediated dUTP nick end labeling(TUNEL) to evaluate the apoptosis in each group.Results The integrate optical density (IOD) value of expression of Bax in the NEC model group began to increase on the 24 h [(1 005.06-± 11.96) IOD] and reached the summit on the 72 h [(3 340.66 ±68.72)] compared with the control group[(666.55 ± 15.77)IOD].A few of TUNEL positive cells began to increase with time dependence.A lot of TUNEL positive cells could be found in NEC model group on the 24 h [(15.04 ± 0.24) ％],and the apoptotic index reached the peak on the 72 h [(35.65 ±0.61) ％] compared with the control group[(4.73 ±0.04) ％,P ＜0.01]-There was a significantly positive correlation between the cell apoptosis and the ratio change of Bax in NEC model group (r =0.94,P ＜ 0.01).Conclusion There is a significantly positive correlation between the cell apoptosis and the ratio change of Bax in enterocytes of neonatal rats with NEC.The cell apoptosis in enterocytes of neonatal rats with NEC maybe be induced by Bax.