Abstract In order to study the influence of chitosan on bone infection, 27 New-Zealand rabbits were randomly divided into 3 groups. According to the Norden technique, the model of osteomyelitis of the tuberosity of tibia was produced experimentally by injection of staphylococcus aureus.Immediately following injection of the staphylococci, the chitosan gel, acetic acid solution and sterile distilled water were injected into the bones in the 3 groups respectively. The latter two groups were served as control. The severity of the infection was evaluated by clinical symptoms and signs, radiographicdata as well as the bone culture and bacterial counts. Compared the results from chitosan with the other two controls, it was found that the local injection ofchitosan could not reduce the incidence of bone infection, however, it could provide actual improvement when other data were concerned. The effects of chitosangel might be attributed to its bacteriostatic and immunological activity as well as its slow degradation in the body.
In order to study the effect of chitin and chitosan on the growth of Schwann cell (SC) of rats in vitro, the SC was isolated from sciatic nerve and brachial plexus of new-born rats. After the enzymatic and mechanical dissociation, the cell suspension was vaccinated on chitin membrane and chitosan fluid-coated glass coverslips. Then, the growth of SC was examined at 1, 3, 7 days after culture under light microscope and scanning electron microscope. The results showed that 94 percent of the cell grown from was SC and only 6% was fibroblast (FB), while that of the control SC 71% and FB 29% in population. The number of SC in chitosan suspension was more than that in chitin. Therefore, the conclusion was that the chitin and chitosan was histocompatible to SC, and chitosan suspension was superior to chitin, and both could inhibit the growth of fibroblast.
In order to investigate the influence on the blood flow direction and pattern at the arterial bifurcation, the mesenteric arterioles of 19 SD rats were observed under the OLYMPUS BH2 surgical microscope. After the rats were anesthetized and the body temperature was kept at 37℃ to 38℃, the mesenteric membrane wasexposed and the pattern and direction of the blood flow of the arterioles whichbifurcated at angle of 45±5°, 90±5° and 135±5° were observed. Results showed that the deformation of RBCs made them easy to adapt to the intravascular geometry and pass by fluently without sticking. It was implied that the alteration in arterial flow direction did not cause turbulance at the bifurcation site, and this in return suggested that in end-to-side anastomosis of small arteries,the flow volume would not be reduced and the chance of thrombosis would not be increased.
The biomaterial, chitin, was used to create a nerve regeneration chamber for bridging healing experiment of sciatic nerve of rats having a defect of 12mm. The crude Schwann cells were introduced into the chambers in one group and the other group had no crude Schwann cells in the chamber and the results of the two groups were compared with those having the nerve defects bridged with skeletal muscles. The specimens were observed by macroscopic, microdissection. electrophysiologic testing, HRP retrograde labelling, histologic and electron microscopic examinations at 4, 8, and 12 weeks after the operation. The results showed that atthe 8th week, the regenerating nerve fibers from the cephalad ends had united with the fibers of the caudal ends of the divided nerves either the crude Schwanneclls were introduced or not, but the morphology of the regenerating nerve, the way of regeneration and the recovery of the function of the extremities were far superior in the group that no cruds Schwann cells had been introduced than those with crude Schwann cell introduced and those bridged by skeletal muscles.