Objective To study the effect of chitosan-pCrmA nanoparticles on the apoptosis of chondrocytes induced by interleukin-1 beta (IL-1β).Methods Chitosan-pDNA nanoparticles were prepared and characterized.The transfection efficiency of chitosan-mediated pIRES2-EGFP was evaluated using fluorescence microscope.The cytotoxicity of chitosan-pIRES2-EGFP nanoparticles in primary rabbit chondrocytes was analyzed by MTT assay.The expression of chitosan-mediated pCrmA in primary rabbit chondrocytes was verified by Western blotting.The effect of chitosan-mediated CrmA on chondrocytes apoptosis induced by IL-1β were analyzed by TUNEL assay.One-way ANOVA was used to analysis.Results The size of chitosan-pDNA nanoparticles was 50 nm.The pDNA release of chitosan-pDNA nanoparticles appeared as biphasic release at pH 2.0 and pH 7.4 buffer.The expression of CrmA in rabbit primary chondrocytes mediated by chitosan could be detected.The chitosan-pIRES2-EGFP nanoparticles had no cytotoxicity.The apoptosis rate of chondrocytes in the chitosan-pCrmA nanoparticles treated group was significantly lower than that of the chitosan treated group (P＜0.05) and PBS group (P＜0.01).Conclsion Chitosan is an effective non-viral gene transfer vector.The CrmA mediated by chitosan can significantly inhibit chondrocytes apoptosis induced by IL-1β,suggesting that chitosan-pCrmA nanoparticles may be the treatment of osteoarthrifis.

Mannosylerythritol lipids (MELs), mainly produced by Ustilago and Pseudozyma, are surface active compounds that belong to the glycolipid class of biosurfactants. MELs have potential application in food, pharmaceutical and cosmetics industries due to their excellent surface activities and other peculiar bioactivities. In recent years, the research field of MELs has regained much attention abroad. However, MELs are rarely studied in China. In this review, the producing microorganisms and production conditions, diverse structures, biochemical properties, structure-function relationship and biosynthetic pathways of MELs are described. Some research problems and prospects are summarized and discussed as well.
Glycolipids ; biosynthesis ; genetics ; Metabolic Networks and Pathways ; genetics ; Surface-Active Agents ; metabolism ; Ustilaginales ; classification ; genetics ; metabolism ; Ustilago ; genetics ; metabolism