Effect of chitooligosaccharides on cyclin D1, bcl-xl and bcl-2 mRNA expression in Hela cells / 中国组织工程研究

BACKGROUND: Studies have shown that chitooligosaccharides have antitumor effect. However, the influence of chitooligosaccharides on cyclin D1, bcl-2 and bcl-xl remains unclear.OBJECTIVE: To observe the JnhJbJtJon effect of chitooligosaccharides on the proliferation of Hela cells, and the influence on cyclin D1, bcl-xl and bcl-2 mRNA expression.METHODS: Hela cells were stimulated by different concentrations of chitooligosaccharides (0.1, 0.5, 1, 2, 5 g/L). The effects of chitooligosaccharides on Hela cells were detected by CCK8 kit. Using real-time PCR methods, the gene expression of cyclin D1, bcl-xl and bcl-2 mRNA were determined.RESULTS AND CONCLUSION: Chitooligosaccharides inhibited the proliferation of Hela cells. With the concentrations of chitoolJgosaccharides increased from 0.1 g/L to 2 g/L, the inhibition effects on the gene expressJon of cyclin D1, bcl-xl and bcl-2 were enhanced, peaked at 2 g/L, and decreased at high concentration (5 g/L). Antitumor activity of chitooligosaccharides may exert through two aspects: it inhibits cyclin D1 mRNA expression to suppress the proliferation of tumor cells; on the other hand, chitooligosaccharides inhibits the expression of bcl-xl and bci-2 to promote the apoptosis of tumor cells. Moreover, the effects of the former are stronger than the latter.

Preparation of chitosan/hydroxyapatite membrane and its effect on cell culture / 生物医学工程学杂志

Compound membranes of chitosan/hydroxyapatite were prepared by blending. The physical performance showed that the air-water contact angles decreased from chitosan's 103 degrees to chitosan/hydroxyapatite's 57 and the water adsorption rate increased slightly. When immersed into culture medium, the materials adsorbed Ca2+, and low crystalline hydroxyapatite deposited on the surface of the membranes. Chitosan/hydroxyapatite compound membranes could enhance the attachment and proliferation of mescenchymal stem cells (MSCs). After 12 days' induction on the materials, the alkaline phosphatase (ALP) activity value of MSCs on the compound membrane was 10.1, being much higher than 1.6 on chitosan membrane (P<0.01). All these results indicate that chitosan does not have very good affinity for MSCs, but the biocompatibility of chitosan can be apparently enhanced after mixing with hydroxyapatite. The compound membrane stimulates MSCs to differentiate into osteoblasts and it may be a good potential material for bone substitution.

Surface modification of poly-D,L-lactic acid film with plasma graft polymerization / 中国组织工程研究

BACKGROUND:Polylactic acid(PLA)surface is hydrophobic and there are no nataral recognition sites,so its application is limited.Many different strategies have been studied such as composition and chemical Drafting,to produce hydrophilic groups.However,these traditional methods are always involved in complex process and many organic reagents,resulting in decrease of biocompatibility.OBJECTIVE:To conduct the surfacr modification of PL.A and improve its hydrophilicity with low temperature plasma treatment.DESIGN:Controlled observation.SETTING:Department of Materials Science and Engineering in Jinan University.MATERIAIS:The experiment was processed from October 2004 to October 2005 at Guangzhou Research Center of Artificial Organs and Materials Engineering(Ministry of Education).The mainly used materials were:Poly-D,L-lactic acid(Mr 2.9×104,Shandong Medical Instrument Institute),N-vinyl-pyrrolidone(NVP,Acros Company,purified before use).METHODS:The materials were treated in the plasma reactor under different conditions(power=150 W,t=3,2,1 minutes;power=30 W,t=10,8,5,3,1 minutes)to choose the optimal condition,and then PLA were grafted with NVP by gas phase polymerization and liquid polymerization,respectively.MAIN OUTCOME MEASURES:THe surface morphology of the films was observed with scanning electron microscopy and atomic force microscopy.The hydrophilicity of native and treated material surfaces was measured using a water contact angle meter.Surface composition was detected with Fourier transform infrared spectrometer.Mass changesmeasurement was applied to characterize the grafting efficiency.RESULTS:Scanning electron microscopy and atomic force microscopy showed that the plasma medified materials possessed coarse surface with pores and notches.Water contact angles decreased obviously from 78°to 50°after grafting,Fourier transform infrared spectrometer showed a new absorption peak at 1 637.19 cm-1,which corresponded to the carbonyl stretch vibration absorption of amide group in poly-N-vinyl-pyrrolidone.After the plasma treatmerlt at low temperature.the mass change ratio of PLA film material was-0.6.CONCLUSION:The plasma treatment and polymerization can improve the hydrophilicity and cause coarsr surface of PLA material,which will be helpful for the cell attachment.