The purpose of this experiment was to elucidate the influence of the low-energy He-Ne laser on the function of regeneration of peripheral nerve. Forty-four rabbits about 2.5 kg body weight were used in the experiment. The animals were divided into 4, 8, 12, 16 weeks groups according to the observation period. Six animals were used in each irradiated group and in the control group 5 rabbits were used in each observation period. Regeneration of the axon and myelinc sheath, the latent rate of the common peroneal nerve, the conditions of the anterior tibital muscle and the toe expansion test were all observed systematically in both groups. The experimental results was: A few thin regenerated axon was seen at 4 weeks in the irradiated group, while in the control group it might be seen at 8 weeks, the P value was lt; 0.01. A low amplitude latent rate of the common peroneal nerve is determined at the peroneal side of the anterior tibial muscle in a few animal at 4 weeks of the irradiated group, and it is not observed in the control group, from 12 to 16 weeks. THe latent rate of the common peroneal nerve was the irradiated group than in the controlled, the P value was lt; 0.01. The regeneration of the myeline sheath was evident in the irradiated group, and also the slstion of the musdle fibers anterior tibial muscle was clearly visible than the controlled. 16 weeks postoperatively, the toe expansion test was normal in the irradiated group, while in the control group it was the same as seen at 12 weeks after operation in the irradiated group. Now it was certain that the low-energy He-Ne laser could promole the function of the spinal motor nerve cells and accelerate the axonal regeneration.
Objective To study the influence of the immersed time by hydrogen dioxide on the characteristics of bovine cancellous bone granules in various periods. Methods Ten 24-month-old Qinchuan bovine, male or female, weighing 150-170 g, were selected. Cancellous bone granules from metaphysic of bovine long bone were cut into cubes of 5 mm × 5 mm ×5 mm and immersed by 8.8 mol/L hydrogen dioxide for 0, 12, 24, 36, 48, 60 and 72 hours separately. Determination of ash, scanning electron microscope, X-ray energy spectrum and micro CT were used to investigate the changes of composition, structure and qual ity of bone. Results With the immersed time increasing, the contents of organics in the bone cancellous were reduced gradually, and obviously decreased during the periods of 0 to 24 hours and 60 to 72 hours (P lt; 0.05). The contents of calcium and phosphorus decreased gradually, they could not be detected almost after 60 days (P lt; 0.05). Bone mineral density and bone mineral content were decreased obviously after 60 hours (P lt; 0.05). The bone trabecula became sl immer and trabecular spacing became larger. Conclusion Hydrogen dioxide can be used to remove the antigen in xenogeneic bone; however as the time increasing (more than 60 hours) the composition and structure will be damaged. Thus it is important to control the immersed time for maintaining the biological characteristics of xenogeneic bone substitute as well as el iminating antigen by hydrogen dioxide.