The study on organic bioactivative materials for clinical application in the tissue regeneration medicine

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IntroductionThis reseach focus on the biodegradation process of the chitin/chitosan filled in the bone defect at the animal study by the useage of lectin (WGA-gold) and the lysozyme as the immuocytochemical marker.Materials and methodsSixty, 6-weeks-old male, Wistar rats were used for this experiment. Chitin and derivatives were divided into three groups of twenty specimens each, hereafter we will call the deacetylated derivatives DAC 0,DAC 50,DAC 100,respectively. The operation approach was made through a skin incision along the inferior border of the mandible. After periosteal flap was elevated, a cavity was prepared into the bone marrow from the bone surface between the mental foramen and the inferior border of mandible. Under a dissecting microscope, four cylindrical cavities were prepared below the external oblique protuberance on each lateral sides of the mandible for each rat. The cotton-like three kinds of different degree of deacetylated chitin was implanted in the each three … More cavities without sealing, respectively, designated DAC(degree of deacetylated chitin) 0,50 and 100 group. At 1,2,3 and 4 weeks postoperatively, the implanted chitosan together with surrounding bone were carefully dissected At the post fixation, the blocks were embedded in LR gold. Undemineralized each group specimens were cut with glass knives for the morphological study. Semithin sections (about 1 μm) were stained with toluidine blue for light microscopy and for the immunocytochemical study we used rabbit polyclonal anti-human lysozyme. We also examined a high-resolution view of ultrastructual localization of chitin remnant on thin sections by the transmission electron microscope.Results and DisccusionIn case of implanting DAC 0,inflammatory cells infiltration was disappeared within 2 weeks postoperatively and the accumulation of lysozyme surrounding chitosan fibers was continued more than 4 weeks. However their degree of the appearance was reduced with time. In case of DAC 50,the early stage inflammation was disappeared within 1 week and the accumulation of lysozyme was not recognized by 2 weeks. In case of DAC 100,the early stage inflammation and the accumulation of lysozyme were not observed by 1 week. These findings suggest that the higher the degree of deacetylation of chitosan, the more rapid the biodegradation and the bone repair. The present study demonstrates that the highly deacetylated chitosan is possible to apply in clinical dentistry such as teeth extraction, apicectomy and periodontal surgery for the rapid bone healing. Less