Study On Effect Of Carboxymethylchitosan With Different Molecular Weight In Skin Wound Healing

Skin wound means skin is hurted by mechanical injury factors. Tissues healing after skin wound is one of the oldest problems in medicine. With the developing of automachinism, skin trauma is more and more popular and the wound becames more and more complex, so it is harder to be treated, especially some patient with diabetes or varicosity. Although some antibiotics, vitamine and microelement preparation are abroad used, their promotive effects are very finitary. Some grow factors have more promotive effects on wound healing, but they are in experimental study phase, because they have much categories and complex matches, or may be cause scar even cancer. So there is important signification to study medicines which have promotive effects on wound healing.Chitin is a kind of polyacetamideglucose macromolecular amylase. Chitosan is the product which is derived by chitin. Because of its resource abundance, nature, non-toxic, non-antigenic specificity, biodegradable and biocompatibility, the study on the characters, functions and appliance of chitosan and its derivitives are wide regarded in recently twenty years. They have wide applications in many fields such as industy agriculture, biology engineering, medicine, food industy, biomedicial materials, aquatic product and chemical industy, especially in the field of medicine. But the applications of chitin and chitosan are limited because they both are not straight soluable. The hydroxyl of chitosan C₆ can be chemical transformed because of its liveness, so the carboxymethylchitosan can be derived by chitosan. Carboxymethylchitosan is soluable, so it shows wide appliance foreground in the field of medicine, cosmetic and biomaterial.In this essay, Chitosan with different molecular weight were prepared by acid degradation and oxidation degradation, CM-Chitosan with different molecular weight is synthesized from corresponding Chitosan. Their physical properties are studied.Staphylococcus aureus and Escherichia coli are used as direction bacteria, MIC method is applied to evaluate the different repress effects. Results demonstrated that CM-Chitosan with different molecular weight can repress the proliferation of Staphylococcus aureus and Escherichia coli. The effects of low molecular weight CM-Chitosan are stronger than high molecular weight CM-Chitosan and the high concentration has more repressive effects. The CM-Chitosan (Mn=3KD) had the strongest promotive effects. MIC of Staphylococcus aureus is 0.5%, MIC of Escherichia coli is 1%.Microscope observation and MTT method are applied to evaluate the different effects on the proliferation of skin fibroblasts and keratinocytes. Results demonstrated that CM-Chitosan with different molecular weight can promote the proliferation of skin fibroblasts and keratinocytes at l¹000ppm and the concentrations at 100 ppm had the strongest effects; The effects of low molecular weight CM-Chitosan are stronger than high molecular weight CM-Chitosan, the CM-Chitosan (Mn=3KD) had the strongest promotive effects on skin fibroblasts and keratinocytes, which had equivalent effects compared with bFGF and EGF.New Zealand rabbits are used to make wound animal model by scalpel shearing. Morphologic and histological sections are applied to study the different effects on wound healing. Results demonstrated that CM-Chitosan with different molecular weight can promote the healing of skin wound at 5% concentration, the CM-Chitosan (Mn=3KD) had the strongest promotive effects on skin wound healing, which ahead of control for five days.All these results indicated that the CM-Chitosan (Mn=3KD) had thestrongest repress effects on StaphyJococcus aureus and Escherichia coli; strongest promotive effects on skin fibroblasts and keratinocytes, which had equivalent effects compared with bFGF and EGF; strongest promotive effects on healing of wound animal model, which provide the theory basis for theoretics study on structure and function, appliance and exploitation of the chitosan and its deritives with low molecular weight.