OBJECTIVE To investigate the possibility of repairing the cartilage cartilage defect with homogeneous chondrocytes combined with Pluronic. METHODS: Homogeneous cartilage chondrocytes of adult New Zealand rabbits were harvested and cultured in vitro, which were marked by 3H-TdR and mixed with Pluronic. The medial or lateral condyle defects were made (phi 4 mm, extending down to the calcified zone) in 20 rabbits. In the experimental group, the right defects were repaired by homogeneous chondrocytes combined with Pluronic; in the control group, the left defects were repaired by Pluronic only or were left un-repaired. The animals were sacrificed in the 4th, 8th and 16th weeks after operation respectively. The repair results were observed and the cell source of repair tissue was distinguished. RESULTS: In the experimental group, the cartilage defects were repaired by the cartilage-like tissue after 8 weeks of operation; the defects were completely filled with mature cartilage tissue, which integrated smoothly with articular cartilage 16 weeks later. In the control group, only a small amount fibrous tissues were seen on the surface of defects. Autoradiographic assessment showed that the repair cells came from the implants, but not from self-chondrocytes. CONCLUSION: It is a good way to repair articular cartilage defects with homograft of tissue engineering cartilage. It is a convenient method to mark with 3H-TdR to discriminate the resource of the repair cells.
Objective To study the functional change of nerve trunk after removing the partial bundles of ulnar nerve, to propose the concept of functional reserve of peripheral nerves and to investigate the functional reserve quantity of peripheral nerves. Methods Two hundred and twenty SD rats (male or female), aging 3 months and weighing 300-350 g, were randomized into the experimental group and the control group (n=110 per group). And the experimental group wassubdivided into group 1/8, group 1/4, group 1/3, group 1/2 and group 2/3 according to the resection portion (n=22 per group). In the experimental group, the section of the lowest level on ulnar nerve trunks was exposed, and a certain portion of its bundles was separated and cut, while in the control group the bundles were only separated without resection. The general condition of all rats was observed, and the motoneurons in cornu anterius medullae spinal is were detected at 1 week, 2 weeks and 2 months after operation. The neuro-electrophysiology and the function of dominated muscles were detected at 2 weeks, 2 months, 3 months, and 4 months after operation. Results All the rats survived without infection and obvious ulcer in the l imbs. The number of motoneurons in cornu anterius medullae spinal is in various experimental subgroups witnessed no obvious changes (P gt; 0.05). The superstructure changed obviously at the early postoperative stage in group 1/2 and group 2/3, but restored well at 2 months after operation. For the latent period of evoked potential, there was no significant difference between the various experimental subgroups and the control group at each time point (P gt; 0.05), but there was a significant difference among the various experimental subgroups when compared the time points of 2, 3 and 4 months to that of 2 weeks (P lt; 0.05) and no statistically significant difference at other time points (P gt; 0.05). For the wave ampl itude of evoked potential of motor nerves, the maximum wave ampl itude and the persistence time of the dominate muscle, there were significant differences between the various experimental subgroups and the control group at each time point (P lt; 0.05), and there were significant differences among the various experimental subgroups when comparing the time points of 2, 3 and 4 months to that of 2 weeks (P lt; 0.05) and no statistical significance at other time points (Pgt; 0.05). Conclusion The functional reserve of the ulnar nerve withoutcompromise accounts the 1/3 of the whole trunk diameter.