The Effect Of Polysaccharide Nanoparticles On Liver Carcinoma Xenografts In Nude Mice And It's Vascular Endothelial Growth Factor Expression

Chitin/Chitosan is one of the most important marine polysaccharides.Chitin and chitosan have attracted more attention in the world due to their good biocompatibility,degradability,low toxicity and special physicochemical properities and biological activities.They have prospective applications in many fields such as biomedicine,chemical industry,light industry and agriculture.The research on application and action mechanism of chitin/chitosan could contribute to the development of glycobiology, glycotechnology and marine drug.With the development of nanotechnology,nanoparticles and nanomaterials have been broadly applied in biomedicine and pharmacy.Reseach on the application of chitosan nanoparticles in drug controlled delivery,targeted drugs and gene carder will provide novel orientation for development of marine glycotechnology drug.In this study,polysaccharide nanoparticles(CNP)were constructed by nanotechnology using polysaccharide(CS)as the raw material.The structure and character of CNP was analyzed,the pathology assay of hepatocellular carcinoma xenografts in nude mice was demonstrated,as well as the vascular endothelial growth factor(VEGF)mRNA levels of hepatocellular carcinoma xenografts in nude mice were detected by fluorescence quantitative PCR.Therefore,the effects of CNP on growth of hepatocellular carcinoma xenografts and expression of VEGF in nude mice were discussed.The main results were as follows:1,Structure and characterization of polysaccharide nanoparticles(CNP):AFM observation indicated that the morphology of CNP was well-proportioned solid sphere and its size ranged from 36.49 to 51.68 nm with a size of 45.19 nm.The average potential was 40.05 mV,it ranged from 25.03 to 56.18 mV with 100%by Zetasizer Nano-ZS90.2,Test of liver carcinoma xenografts in nude mice and tumor pathology:Twelve female athymismus nude mice(6-week-old)were used in this study.After the period of acclimation,animals were randomly divided into four groups(M1,M2,M3,control(M4)).The nude mice were vaccinated with 2×10~6/0.5 ml human liver cancer cell line BEL7402 containing matrigel in the back skin for 7 to 10 days.As tumor diameter was about 0.5 cm(the standard is tumor diameter of 0.4 cm to 0.5cm),M1 was fed a 30mg/kg·Only CNP solution,M2 was fed a 60mg/kg·Only CNP solution,M3 was fed a 90mg/kg·Only CNP solution,Control(M4)was fed a physiological saline by intragastric administration.The result of liver carcinoma xenografts experiment in nude mice showed that the curve slope of the experimental groups of M1,M2 and M3 were 15.223,11.983 and 6.1851,respectively.In this experiment,it was showed that the more dose of CNP,the slower growth speed of tumor.Therefore,CNP could inhibit the growth of tumor.Tumor pathological test showed that after 21-day CNP administration,electron microscopy showed that the tumor cell morphology was complete and cell microvilli was rich in the control group.However, necrosis pathology changes of the tumor tissue with necrosis cells and degenerative cells,pyknosis,nuclear homogenization dissolved and nuclear fragmentation could be observed by transmission electron microscopy in the trial group.In the cytoplasm,there were a large number of vacuolus.Moreover,cells debris,swelling empty mitochondrial,dilated endoplasmic reticulum vesicles and fibrosis lesions could be investigated.Thus,CNP can promote tumor necrosis lesions.3,Fluorescence quantitative PCR experimentThrough the administration of different doses CNP for 21 days,it showed that the relative level of VEGF mRNA expression(M3,M2,M1,Control)were 0.02933,0.06731,0.1052,0.1465,respectively,by fluorescence quantitative PCR detection.It was demonstrated that when the dose of CNP increased,the levels of VEGF mRNA expression were reduced,indicating that there were some dose-effect relationship. Therefore,it was revealed that CNP could inhibit vascular endothelial growth factor(VEGF)gene mRNA expression.In conclusion,CNP could destroy the cell membrane and subcellular structure of tumor,resulting in the necrosis lesions of hepatocellular carcinoma cells.The expression mRNA level of VEGF was inhibited by CNP.Therefore,the growth and development of tumor was suppressed via angiogenesis blocking.