The growing inhibition action of PEG modified magnetic 5-Fluorouracil albumin microspheres combined with constant external magnetic fields on human colon carcinoma LoVo cells in vitro

Abstract

Objective To investigate the growth inhibiting action of PEG modified magnetic 5-Fluorouracil albumin microspheres (PEG-5-FU-MAMS) combined with constant external magnetic fields on human colorectal carcinoma LoVo cells in vitro and the mechanism. Methods The PEG-5-FU-MAMS were prepared by emulsification/solidification method.The cultured LoVo cells were divided into four groups.Group A was processed with PEG-5-FU-MAMS combined with external magnetic fields, group B was PEG-5-FU-MAMS without magnetic fields, group C was free 5-FU, group D was pure magnetic field.The growth of LoVo cells was observed under an inverted microscopy, and the inhibitory rate (IR) was assayed by methyl thiazol tetrazolium (MTT) assay. Results The obtained microspheres (MS) were spherical and about (1.32±0.50)μm in size.The drug loading was (5.31±0.13)% and the MS had good magnetic responsibility.The release rate of 5-Fu in vitro showed that PEG-5-FU-MAMS had pronounced sustained-release effect.LoVo cells grew well and had good refraction after 24 h. Under the microscope, tumor cells were completely adherent.After different treatment, the tumor growth showed no difference on tumor cells in pure magnetic group.The IR of pure PEG-5-FU-MAMS group and free 5-FU group at same drug concentration were similar, there were no significant differences between them(q=2.02, 2.11, 2.74; P>0.05). Compared with pure PEG-5-FU-MAMS and free 5-FU group, when the concentration of 5-FU exceeded 10.0 mg/L, IR was significantly increased after PEG-5-FU-MAMS combined with constant external magnetic fields(F=62.09, 66.74, 56.62, 66.13; P<0.05). Conclusions PEG-5-FU-MAMS is characterized with good shape, particle size, drug loading, magnetic responsibility and drug release.The growth inhibiting action is significantly enhanced after PEG-5-FU-MAMS combined with constant external magnetic fields. Key words: Fluorouracil; Albumins; Microspheres; LoVo cells