Objective To investigate the feasibil ity of building the 3D reconstruction of short segment common peroneal nerve functional fascicles based on serial histological sections and computer technology. Methods Five cm of the common peroneal nerve in the popl iteal fossa, donated by an adult, was made into the serial transverse freezing sections(n=200) at an interval of 0.25 mm and 10 μm in thickness per section. Acetylchol inesterase staining was adopted and the nerve fascicles were observed by microscope. 2D panorama images were acquired by high-resolution digital camera under microscope (× 100) and mosaic software. Different functional fascicles were distinguished and marked on each section. The topographic database was matched by image processing software. The 3D microstructure of the fascicular groups of 5 cm common peroneal nerve was reconstructed using Amira 3.1 3D reconstruction software. Results Based on microanatomy and the results of acetylchol inesterase staining, this segmented common peroneal nerve functional fascicles was divided into sensory tract, motor tract, mixed tract and motor-predominating mixed tract. The cross merging was not evident in the nerve fascicles between deep peroneal nerve and superficial peroneal nerve, but existed within the functional fascicles of the deep peroneal nerve and the superficial peroneal nerve. The results of 3D reconstruction reflected the 3D structure of peripheral nerve and its interior functional fascicles factually, which displayed solely or in combination at arbitrary angles. Conclusion Based on serial histological sections and computer technology, the 3D microstructure of short-segment peripheral nerve functional fascicles can be reconstructed satisfactorily, indicating the feasibil ity of building 3D reconstruction of long-segmental peripheral nerve functional fascicles.
Objective To investigate the feasibility of fabricating an oriented scaffold combined with chondrogenic-induced bone marrow mesenchymal stem cells (BMSCs) for enhancement of the biomechanical property of tissue engineered cartilage in vivo. Methods Temperature gradient-guided thermal-induced phase separation was used to fabricate an oriented cartilage extracellular matrix-derived scaffold composed of microtubules arranged in parallel in vertical section. No-oriented scaffold was fabricated by simple freeze-drying. Mechanical property of oriented and non-oriented scaffold was determined by measurement of compressive modulus. Oriented and non-oriented scaffolds were seeded with chondrogenic-induced BMSCs, which were obtained from the New Zealand white rabbits. Proliferation, morphological characteristics, and the distribution of the cells on the scaffolds were analyzed by MTT assay and scanning electron microscope. Then cell-scaffold composites were implanted subcutaneously in the dorsa of nude mice. At 2 and 4 weeks after implantation, the samples were harvested for evaluating biochemical, histological, and biomechanical properties. Results The compressive modulus of oriented scaffold was significantly higher than that of non-oriented scaffold (t=201.099, P=0.000). The cell proliferation on the oriented scaffold was significantly higher than that on the non-oriented scaffold from 3 to 9 days (P lt; 0.05). At 4 weeks, collagen type II immunohistochemical staining, safranin O staining, and toluidine blue staining showed positive results in all samples, but negative for collagen type I. There were numerous parallel giant bundles of densely packed collagen fibers with chondrocyte-like cells on the oriented-structure constructs. Total DNA, glycosaminoglycan (GAG), and collagen contents increased with time, and no significant difference was found between 2 groups (P gt; 0.05). The compressive modulus of the oriented tissue engineered cartilage was significantly higher than that of the non-oriented tissue engineered cartilage at 2 and 4 weeks after implantation (P lt; 0.05). Total DNA, GAG, collagen contents, and compressive modulus in the 2 tissue engineered cartilages were significantly lower than those in normal cartilage (P lt; 0.05). Conclusion Oriented extracellular matrix-derived scaffold can enhance the biomechanical property of tissue engineered cartilage and thus it represents a promising approach to cartilage tissue engineering.