Distribution of neuronal nitric oxide synthase-immunopositive neurons in rat corpus striatum and their ultrastructures / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the distribution of neuronal nitric oxide synthase (nNOS)-immunopositive neurons in rat corpus striatum and their ultrastructural features.</p><p><b>METHODS</b>Brain tissue specimens were obtained from normal SD rats, in which nNOS-immunopositive neurons were visualized by ABC immunocytochemistry and observed under immunoelectron microscope with pre-embedding staining.</p><p><b>RESULTS</b>Under light microscope, nNOS-immunopositive neurons appeared brown with distinct profiles of the cell body and processes. These neurons, mostly medium-sized and small cells, were located mainly in the lateral region of the corpus striatum. Only a few immunopositive neurons were detected in the medial region of the corpus striatum. Immunohistochemistry and transmission electron microscopy identified the nNOS-immunopositive neurons as interneurons possessing large nuclei with small amount of cytoplasma. The immunopositive granules were visualized as black plaques, and the larger ones distributed mainly in the cell bodies, some with monolayer membrane encapsulation. The small granules did not have the encapsulation, scattering in perinuclear regions and under the cell membrane, but not in the cell body. The immunopositive granules were also found in the axons and dendrites, but not in the vesicles of the synapses. In addition, many immunopositive terminals were found close to the blood vessels.</p><p><b>CONCLUSIONS</b>nNOS-immunopositive neurons in rat corpus striatum are mainly medium-sized and small cells as is typical of the interneurons. The immunopositive granules locate in the cytoplasma, axons and dendrites, and larger granules have membrane coating while small ones do not, possibly in relation to their functions.</p>

Construction of artificial nerve bridge by three-dimensional culture of interleukin-1beta- activated Schwann cells with human hair keratins / 南方医科大学学报

<p><b>OBJECTIVE</b>To culture interleukin-1beta (IL-1beta)-activated Schwann cells (SCs) with human hair keratins (HHKs) for artificial nerve bridge construction.</p><p><b>METHODS</b>SCs purified by primary culture with or without IL-1beta activation were cultured with HHKs decorated by extracellular matrix (ECM), and the artificial nerve bridge was implanted into the defect of rat sciatic nerve. The morphology of the SCs cultured with HHKs was monitored by inverted microscope, scanning electron microscope and evaluated by immunocytochemical staining, and the expression of nerve growth factor (NGF) in the sciatic nerve was observed by in situ hybridization.</p><p><b>RESULTS</b>Activated SCs showed better ability to adhere to the HHKs and grew well. The HHKs component in the artificial nerve bridge underwent degradation in the sciatic nerve defect after 3 to 4 weeks, and IL-1beta activation resulted in enhanced NGF expression in the SCs.</p><p><b>CONCLUSION</b>The constructed artificial nerve bridge by three-dimensional culture of IL-1beta-activiated SCs with HHKs decorated by ECM promotes the repair of sciatic nerve defects and accelerates sciatic nerve regeneration.</p>