In order to study the influence of severity of tendon injury on the morphology of collagen fibers during healing process of extensor tendons, 40 female Wistal rats were used for investigation. The rats were divided into 2 groups. Transection of the tendon of extensor digitorum longus was performed in one group, while partial section of the same tendon was performed in the other group. Morphometric analysis was undertaken on the 15th, 30th, 60th and 90th day after operation. The result was that there was no significant difference between the two groups both in distribution and diameter of collagen fibers on the 15th and 30th days (P gt; 0.05). However, there was significent difference between those on the 60th and 90th days (P lt; 0.05). It was concluded that the severity of the tendon injury could influence the morphology of collagen fibers during the late stage of tendon healing.
OBJECTIVE: To study the characteristics of, morphology histology and ultrastructure of anterior cruciate ligament(ACL) autograft and two-step cryopreserved ACL allograft after transplantation. METHODS: Sixty New Zealand rabbits and sixty Japanese rabbits were randomly divided into two groups: ACL autograft group and two-step cryopreserved ACL allograft group. Immunosuppressant were not used after transplantation. The histology and ultrastructure of the ACL of transplantation and normal knee were observed after 4 weeks and 12 weeks, respectively. RESULTS: The rate of remodeling process was faster in ACL autograft than in two-step cryopreserved ACL allograft, but there was similar remodeling process between two groups 12 weeks after transplantation. The proportions of large-diameter fibers(gt; or = 80 nm) of ACL autograft and cryopreserved ACL allograft were 6% and 24% in the 4th week, and were 0 and 2% in the 12th week, respectively. The proportions of small-diameter of fibers(lt; 80 nm) of ACL autogrft and cryopreserved ACL allograft were 94% and 76% in the 4th week, and 100% and 98% in the 12th week, respectively. Histologic incorporation in ACL autograft was similar to that in cryopreserved ACL allograft. CONCLUSION: Two-step cryopreserved bone-ACL-bone allograft were similar to bone-ACL-bone autograft cryopreserved in remodeling process and histology. The rate of remodeling process was faster in ACL autograft than in cryopreserved ACL allograft.
In order to investigate the effect of nerve compression on neurons, the commonly used model of chronic nerve compression was produced in 48 SD rats. The rats were sacrificed in 1, 2, 3, 4, 5 and 6 months after compression, respectively. The number of neuron and ultrashruchure of alpha-motor neurons and ganglion cells of the corresponding spinal segment were examined. The results showed as following: After the sciatic nerve were crushed, the number of neuron and ultrastructure of alpha-motor neurons and ganglion cells might undergo ultrastructural changes, and even the death might occur. These changes might be aggravated as the time of crushing was prolonged and the compression force was increased. It was concluded that for nerve compression, decompression should be done as early as possible in order to avoid or minimize the ultructural changes of the neuron.
Objective To observe the relationship of osteoblasts, endothelial cells and ceramic scaffold during reconstruction of rat critical size calvarial defects with tissue engineering technique under transmission electron microscope. Methods Fourteen male adult Sprague Dawley rats were divided randomly into experimental and control groups. Bone marrow was obtained from left femurs and tibias of all rats. In experimental group, respective autogenous osteoblasts derived from bone marrow stromal cells(MSCs) different iated and proliferated in vitro and then were seeded and subcultured on porous calcium phosphate ceramics. The cell-ceramic compounds were used to repair critical-sized (8 mm diameter) calvarial defects in the corresponding rats. In control group, the ceramic without autogenous osteoblosts was used. One rat of each group was sacrificed postoperatively in the 4th, 8th, 12th, 24th, 28th weeks respectively and involved samples were removed to make decalcified ultrath in sections and observed under transmissionelectron microscope. Results Osteoblasts or osteoblast-like cells always located next to sprouting capillaries and the relationship between osteoblasts and endothelial cells was relevant in experimental group. There was a calcium depositzone distributed along the boundary of newly formed bone and the remnants of decalcified ceramic, which meant osseointegration between the ceramic and newly formed bone. The above changes did not appear in control group simultaneously.Conclusion The nanometer scale structure of ceramic scaffold benefits to angiogenesis, osteogenesis and extracellular matrix formation in repair bone defects with tissue engineering technique.
Objective To observe the ultrastructure of theca interna of the de-endothelium allogenetic blood vessels in dogs by transmission and scanning electron microscope at different phases. Methods The endothelium of the allogenetic blood vessels were first removed and cryodensiccated, and were then end to end anastomosed to canine femoral artery. Samples were collected and observed with scanning and transmission electron microscope on the first, second, fourth, eighth, twelfth, sixteenth, and twentieth week after transplantation, respectively. Results A layer of cellulose membrane was formed on the surface of allogenetic blood vessels one week after transplantation; Fusiform cells were observed at the anastomotic stoma of the allogenetic blood vessels two weeks after transplantation, and theca interna, which was covered by fusiform cells and elliptical erythrocytes, was formed twelve weeks later; Slightly hyperplastic smooth muscle cells and collagenous fibers were observed under the endothelium twelve to twenty weeks after transplantation. Conclusion The endothelium cells could cover the surface of the allogenetic blood vessels without remarkable hyperplasia of intima during a short period of time, which may suggest the satisfactory histocompatibility of canine allogenetic blood vessels.
Objective To probe the change of the structure and function of the small bowel by injection of different drugs (verapamil, energy compounds or normal saline) via the superior mesenteric artery (SMA) injections.Methods The model of the small intestine ischemia/reperfusion (I/R) injury was made in grey rabbits. Free calcium concentration in mitochondria of the small intestine was determined, and the ultrastructural change was also observed by electron microscopy at the very time of occlusion, 60 minutes after occlusion and 30 minutes after reperfusion. Results The free calcium concentration in mitochondria was more declined in verapamil group (2.976±0.410 nmol/mg.prot) than in N.S. group (4.234±0.542 nmol/mg.prot), Ｐ＜0.01, at 60 minutes after occlusion. At 30 minutes after reperfusion, free calcium concentration in mitochondria was more decreased in energy compunds group (2.401±0.323 nmol/mg.prot) and verapamil group (3.847±0.610 nmol/mg.prot) than in the N.S. group (5.981±1.031 nmol/mg.prot). Conclusion Verapamil and energy compouds have protective effects on the functions and ultrastructures of the I/R of small intestine.
Objective To isolate，culture and expand bone marrow mesenchymal stem cells （MSCs） in vitro，induce MSCs to differentiate directionally towards chondrocytes，and provide experimental basis for clinical application of MSCs and construction of tissue engineering tracheal cartilage. Methods Cultured MSCs were isolated from bone marrow of Sprague-Dawley rats，purified using adherence separation，and identified by flow cytometry analysis. Transforming growth factor β1 （TGF-β1）and insulin-like growth factor 1 （IGF-1） were used as main induction factors to induce MSCs to differentiate directionally towards chondrocytes. The expression of collagen typeⅡwas evaluated by immunocytochemical staining 21 days after induction. Light microscope and electron microscope were used to observe tiny and ultrastructural changes of the cells before and after induction. Results The expression of collagen typeⅡwas positive by immunocytochemical staining 21 days after induction. MSCs were fusiform before induction under light microscope and electron microscope. After induction，the cells became larger，polygon，star-shaped or triangular. Transmission electron microscope showed that the cells had abundant organelles，larger nuclei and more nucleoli after induction. Conclusion Abundant organelles，larger nuclei and more nucleoli are the ultrastructure changes of chondrocytes differentiated from MSCs，indicating that the cells are active in differentiation and metabolism.
OBJECTIVE To investigate possibility of cartilage cultured in centrifuge tube as graft materials. METHODS: Articular chondrocytes isolated from a 3-week-old rabbit formed cartilage after cultivation for 2 weeks. Articular cartilage of humeral head, growth plate of proximal tibia and meniscus were collected from a 6-week-old rabbit. The ultrastructure of chondrocytes and extracellular matrix in the three kinds of cartilages and cultured cartilage were observed by transmission electronic microscopy. RESULTS: Cartilage cultured in centrifuge tube possessed unique ultrastructure and was similar to articular cartilage and growth plate, but it was markedly different from meniscus. The four kinds of cartilages were characteristic of respectively different chondrocytes and extracellular matrix. Cultured cartilage showed typical apoptosis of chondrocytes and "dark chondrocytes" appeared in growth plate. Condrocyte apoptosis was not seen in articular cartilage and meniscus. CONCLUSION: Cartilage cultured in centrifuge tube has unique ultrastructure and may be used as graft materials for articular cartilage and growth plate.
The DNA content, cellular ultrastructure and the expression of blood group Y antigen and immunosuppressive acidic protein-2(IAP-2) were observed in normal breast, cystic hyperplasia of breast and breast cancer. The results showed: the results observed in the cells of cystic hyperplasia with epithelial proliferation grade Ⅰ were similar to those in normal breast cells. The DNA content increased, the hypoplasia and dedifferentiation features in some structures of cellular membrane and nucleus were observed, and the abnormal antigens expressed in part of the atypical hyperplasic cells. The DNA content and ultrastructure in a part of cells with aypical hyperplasia grade Ⅲ were similar to those in the cells of breast cancer grade Ⅰ. The results indicated that in the couse of atypical hyperplasia, the biological abnormalities and its extent of those cells were closely related to the differentiation extent, the developing tendency and the risk of canceration of the cystic hyperplasia of breast.
A simple model of canine auto-trasplantation of liver was set up by ourselves, and the effects of hepatic artery ischemia (HAI) on ultrastructure of liver and biliary duct transplanted were observed. The results showed that the liver and biliary cells swelled slightly, mitochondrial matrix was loose and ridges were vague just often perfusion. Afte HAI for 3 hours the edema of hepatic and biliary cells aggravated cytoplasm was loose, mitochondria enlarged and partly vacuolar degenerated, ridges broke or disappeared, flocculent focal densites was seen in the matrix, endoplasmic retculum distended obviously, and the ribosome depolymerizated. So we consider that HAI causes obvious damage to hepatic and biliary cells. These indicate that HAI is one of the important factors of complication after liver transplantation, especially some biliary complications.
