| [Background and Purpose] Chitosan is a deacetyled product of chitin which is a polysaccharide found in the exoskeleton of shellfishes such as shrimp , crabs and algae. Naturally there are about 1×109~1×1011 tones of chitin produced everyday on the earth, that means the second inexhaustible and recycling organic resource with no pollution. There are many biological activities of chitin and chitosan such as immune regulation, anti-tumor, anti-infection decreasing blood fat and blood sugar, and so on. Chitosan and chitin are difficulty to be absorbed through intestinal because of their large molecules and low water-solubility. The modification of molecular of chitin has become a focus field. It has been demonstrated that the degraded oligosaccharide of chitin of chitosan with smaller molecules are water soluble and easy to enter tissue. They can play an important role of anti tumor and increasing immune ability in vivo.The purpose of this study is to investigate the mechanism of anti-tumor effect of chitosan oligosaccharide . Five different types of chitosan oligosaccharide were tested by the inhibition of tumor growth and detection of mouse immune ability. The results were benefit for developing of new kinds of antineoplastic drugs .[Materials and Methods ] 1.Effect of chitosan oligosaccharideon the inhibition of S180 tumor: Each ICR mouse was inoculated with 0.2ml of S180 tumor cell suspension (concentration of 2×107/ml), and then from the 2nd to the 8th day each ICR mouse was intravenous injected with chitosan oligosaccharide solution once a day. On the 9th day the tumor on mouse body was obtained and the inhibitive rate was calculated.2.Effect of chitosan oligosaccharide on the inhibition of Lewis lung cancer:C57BL/6 mouse was subcutaneous injected with 0.2ml of Lewis lung caner cell suspension (concentration of 1 × 106/ml) each body, From the 2nd to the 12th day different kinds of chitosan oligosaccharide solution were mainlined through tail vein once a day. On the 13th day the tumor on mouse body was obtained and the cancer inhibition rate (%) was calculated.3 .Effect of chitosan oligosaccharide on the inhibition of spontaneous metastasis of Lewis lung cancer:C57BL/6 mouse was intramuscular injection with 0.2ml of Lewis lung caner cell suspension ( concentration of 1 × 106/ml) 0.2ml each body. From the 2nd to the 12th day No. 5 chitosan oligosaccharide solution was mainlined through tail vein once a day. On the 13th day the lung was obtained and cancer metastasis rate (%) and the number of metastatic focus were calculated.4.Effect of chitosan oligosaccharide on the inhibition of lung metastasis of B16 melanoma through blood vessel: C57BL/6 mouse was injected through tail vein every two day with 0.2ml of B16 melanoma cell suspension (concentration of 5 × 105/ml) each body. From the 2nd to the 17thday No. 5 chitosan oligosaccharide solution was mainlined through tail vein once a day. On the 18th day the lung was obtained and cancer metastatic rate (%) and the number of metastatic focus were calculated.5.Determination of T lymph cells proliferation activity Mice loaded C57BL/6 tumor cells were mainlined through tail vein with three concentrations of Chitosan oligosaccharide of type V in every two days for 6 times. Spleen was obtained after stopping mainline in aseptic condition. The cell was separated and the bean protein A (Con-A) was used as inductor, and 3H-TdR assay was used to determine the transformatic activity of T cell.6.Determination of NK cell activity :The mice were given drugs as metioned above, the YAC-1 cells being the target cells, and 3H-TdR assay was used to determine the NK cell activity.7.Determination of IL-2, IFN-γ serum level: The mice given drugs as item 5, serum was separated from blood, then the ELISA assay was used to determine the serum level of IL-2 and IFN- γ .8. Determination of hemolysin level: Colorimetry assay was used to determine the hemolysin of mice loaded C57BL/6 tumor cells, results represent by HC50. 9.Determination of pha... |
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