Carboxymethyl-chitosan and carboxymethyl-chitin were prepared with the methods developed in our laboratory. The DS （degree of substitution） and DD （degree of deacetylation） of the carboxymethyl-chitosan were 103.1...Carboxymethyl-chitosan and carboxymethyl-chitin were prepared with the methods developed in our laboratory. The DS （degree of substitution） and DD （degree of deacetylation） of the carboxymethyl-chitosan were 103.14% and 97.18% respectively, while the DS of the carboxymethyl-chitin was 96.37%. Their effects on human fibroblasts, intradermal irritation test, in vitro and vivo degradability, and biocompatibility were evaluated. The results indicate that the polysaccharides at low concentrations can facilitate the growth of human fibroblasts and the carboxymethyl-chitosan at 100 μg mL^-1 is the most effective. The polysaccharides at higher concentrations, however, inhibit the growth of fibroblasts. The PII （Primary Irritation Index） values of CM-chitosan and CM-chitin are both 0.0, which shows that they have no irritation reaction. Both of the polysaccharides show good degradability and biocompatibility. Carboxymethyl-chitin degrades faster in vitro than carboxymethyl-chitosan. The latter, however, has no inflammatory reaction after being implanted in vivo for 7 d and shows better biocompatibility. This study may provide a scientific basis for the use of earboxymethyl-ehitosan and carboxymethyl-chitin as biomaterials.展开更多
Effects of carboxymethyl-chitosan with different molecular weights on wound healing were investigated in vivo and in vitro.A second degree burn model was performed in rats and the accelerative effects of carboxymethyl...Effects of carboxymethyl-chitosan with different molecular weights on wound healing were investigated in vivo and in vitro.A second degree burn model was performed in rats and the accelerative effects of carboxymethyl-chitosan on wound repair were observed.Contents of transforming growth factor(TGF)-β1,interleukin(IL)-6 and matrix metalloproteinase(MMP)-1 in wounds were determined by enzyme-linked immunosorbent assay(ELISA).In vitro study evaluated the influence of carboxy-methyl-chitosan on cytokines secretion of fibroblasts and macrophages.In vivo results showed that carboxymethyl-chitosan effec-tively accelerated the wound healing process in burned rats(P<0.05).Levels of TGF-β1,IL-6 and MMP-1 in carboxymethyl-chitosan groups were significantly elevated,compared with control group(P<0.05).In vitro results indicated that carboxymethyl-chitosan significantly promoted the proliferation of fibroblasts and stimulated its IL-8 and IL-10 secretion at different incubation time,but it did not affect collagen secretion of fibroblasts.Carboxymethyl-chitosan enhanced phagocytosis ability of macrophages,and in-creased its tumor necrosis factor(TNF)-α secretion.In conclusion,carboxymethyl-chitosan promoted wound healing by activating macrophages,accelerating fibroblasts growth and exerting considerable effects on the secretion of a series of cytokines.展开更多
In this study,different molecular weight(MW)carboxymethyl chitosans(CM-chitosan)nanoparticles were prepared by ionic gelification.The particle size of nanoparticles was around 180–250 nm by dynamic light scattering(D...In this study,different molecular weight(MW)carboxymethyl chitosans(CM-chitosan)nanoparticles were prepared by ionic gelification.The particle size of nanoparticles was around 180–250 nm by dynamic light scattering(DLS)and transmission electron microscope(TEM).With the increase of CM-chitosan nanoparticles concentration from 2 to 200μg/mL,the growth inhibition effects on the keloid fibroblast increased.At the concentration of 100μg/mL,CM-chitosan nanoparticles withMW6.3 kDa had a significant inhibitory effect(inhibition ratio 48.79%)of the proliferation of keloid fibroblast.Compared with CM-chitosan solution,the inhibition of CM-chitosan nanoparticles were lower in prior period and similar in later period.By analyzing the different effects of chitosan,CM-chitosan solution and CM-chitosan nanoparticles on proliferation of keloid fibroblast,we have found that the carboxylmethyl groups of CM-chitosan play an important role in inhibition of proliferation of keloid fibroblast.展开更多
基金the China ‘863’ High-technology Development Program (No 2003AA625050)
文摘Carboxymethyl-chitosan and carboxymethyl-chitin were prepared with the methods developed in our laboratory. The DS （degree of substitution） and DD （degree of deacetylation） of the carboxymethyl-chitosan were 103.14% and 97.18% respectively, while the DS of the carboxymethyl-chitin was 96.37%. Their effects on human fibroblasts, intradermal irritation test, in vitro and vivo degradability, and biocompatibility were evaluated. The results indicate that the polysaccharides at low concentrations can facilitate the growth of human fibroblasts and the carboxymethyl-chitosan at 100 μg mL^-1 is the most effective. The polysaccharides at higher concentrations, however, inhibit the growth of fibroblasts. The PII （Primary Irritation Index） values of CM-chitosan and CM-chitin are both 0.0, which shows that they have no irritation reaction. Both of the polysaccharides show good degradability and biocompatibility. Carboxymethyl-chitin degrades faster in vitro than carboxymethyl-chitosan. The latter, however, has no inflammatory reaction after being implanted in vivo for 7 d and shows better biocompatibility. This study may provide a scientific basis for the use of earboxymethyl-ehitosan and carboxymethyl-chitin as biomaterials.
基金supported by a grant from National High-Tech R&D Program of China (863 Program, 2007AA091603)
文摘Effects of carboxymethyl-chitosan with different molecular weights on wound healing were investigated in vivo and in vitro.A second degree burn model was performed in rats and the accelerative effects of carboxymethyl-chitosan on wound repair were observed.Contents of transforming growth factor(TGF)-β1,interleukin(IL)-6 and matrix metalloproteinase(MMP)-1 in wounds were determined by enzyme-linked immunosorbent assay(ELISA).In vitro study evaluated the influence of carboxy-methyl-chitosan on cytokines secretion of fibroblasts and macrophages.In vivo results showed that carboxymethyl-chitosan effec-tively accelerated the wound healing process in burned rats(P<0.05).Levels of TGF-β1,IL-6 and MMP-1 in carboxymethyl-chitosan groups were significantly elevated,compared with control group(P<0.05).In vitro results indicated that carboxymethyl-chitosan significantly promoted the proliferation of fibroblasts and stimulated its IL-8 and IL-10 secretion at different incubation time,but it did not affect collagen secretion of fibroblasts.Carboxymethyl-chitosan enhanced phagocytosis ability of macrophages,and in-creased its tumor necrosis factor(TNF)-α secretion.In conclusion,carboxymethyl-chitosan promoted wound healing by activating macrophages,accelerating fibroblasts growth and exerting considerable effects on the secretion of a series of cytokines.
基金This work was supported by the National Natural Science Foundation of China(Grant No.81071274).
文摘In this study,different molecular weight(MW)carboxymethyl chitosans(CM-chitosan)nanoparticles were prepared by ionic gelification.The particle size of nanoparticles was around 180–250 nm by dynamic light scattering(DLS)and transmission electron microscope(TEM).With the increase of CM-chitosan nanoparticles concentration from 2 to 200μg/mL,the growth inhibition effects on the keloid fibroblast increased.At the concentration of 100μg/mL,CM-chitosan nanoparticles withMW6.3 kDa had a significant inhibitory effect(inhibition ratio 48.79%)of the proliferation of keloid fibroblast.Compared with CM-chitosan solution,the inhibition of CM-chitosan nanoparticles were lower in prior period and similar in later period.By analyzing the different effects of chitosan,CM-chitosan solution and CM-chitosan nanoparticles on proliferation of keloid fibroblast,we have found that the carboxylmethyl groups of CM-chitosan play an important role in inhibition of proliferation of keloid fibroblast.
