ABSTRACT
Objective To investigate the changes and their significance of glutamate-aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) expressions in glial cells following spinal cord injury (SCI) in adult rats.Methods Twenty-five healthy female adult SD rats were randomly divided into control group (5 rats) and experimental group (20 rats).The contusive spinal cord injury models were prepared at T10 segment in the rats in the experimental group according to the modified Allen's method.At days 1,3,7 and 14 following SCI,five rats were sacrificed by cardiac perfusion and the spinal cord segments adjacent to the epicenter of injury were obtained at each time point after the neurological function of hind limbs was assessed using the modified Tarlov scale.Changes of GLAST and GLT-1 expressions were detected semi-quantitatively using immunofluorescence and computer image analysis system (IPP 6.0).Results (1) Single immunofluorescence:Moderate GLAST expression was found in the control group.The GLAST expression was increased slightly at day 1 after SCI,decreased progressively at days 3 and 7 after SCI,and increased slightly at day 14 after SCI.The GLAST expression in experimental group was significantly lower than those in control group at days 3,7 and 14 after SCI (P ＜ 0.05).Moderate GLT-1 expression was detected in the control group.The expression of GLT-1 was increased slightly at day 1 after SCI,decreased to the lowest at day 3 after SCI,and increased slightly at days 7 and 14 after SCI.The GLT-1 expression in experimental group was significantly lower than those in control group at days 3,7 and 14 after SCI (P ＜0.05).(2) Double immunofluorescence:GLAST expression was found on astrocytes in the control group.The GLAST expression in experimental group was decreased at day 1 after SCI,further decreased progressively at days 3 and 7 after SCI,and started to recover at day 14 after SCI.The coexpressions of GLAST and glial fibrillary acidic protein (GFAP) in experimental group were significantly lower than those in the control group at days 3 and 7 after SCI (P ＜ 0.05).The expression of GLAST was found on microglial cells in the control group.The expression of GLAST in experimental group was increased obviously at day 1 after SCI and increased progressively at days 3-14 after SCI.The coexpressions of GLAST and OX-42 in experimental group were significantly than those in the control group at days 3,7 and 14 after SCI (P ＜ 0.05).(3) Double immunofluorescence:GLT-1 expression was found on astrocytes in the control group.The GLT-1 expression was decreased at day 1 after SCI,further decreased progressively at days 3 and 7 after SCI,and started to recover at day 14 after SCI.The coexpressions of GLT-1 and GFAP were significantly lower than those in the control group at days 3 and 7 after SCI (P ＜ 0.05).The GLT-1 expression was found on microglial cells in the control group.The GLT-1 expression was increased obviously at day 1 after SCI and increased progressively at days 3-14 after SCI.The coexpressions of GLT-1 and OX-42 were significantly higher than those in the control group at days 1,3,7 and 14 after SCI (P ＜ 0.05).Conclusion The glutamate transporters GLAST and GLT-1 show different expression patterns in astrocytes and microglia following SCI in rats,which may be correlated with the roles of different glial cells in repair of spinal cord injury.
ABSTRACT
OBJECTIVE: To investigate the in vivo possibility of osteogenesis and angiogenesis of tissue-engineered periosteum in rabbits.METHODS: The marrow mesenchymal stem cells (MSCs) derived from New Zealand rabbits were adhered to small intestinal submucosa (SIS) to fabricate the tissue-engineered periosteum. Totally 12 New Zealand rabbits were received critical bone defect in bilateral radii to prepare models. The tissue-engineered periosteum was randomly implanted in one side of bone defect,and the other side was treated by SIS. At 4 weeks after operation, the angiogenesis of tissue engineered bone was detected by Tetracycline fluorescence microscopy and formaldehyde-ink perfusion method; simultaneously, the new bone formation was firmed by haematoxylin-eosin staining.RESULTS: Animals showed normal daily behaviors and non-infection wounds healing. The gross observation showed that bone defects in the experimental side were bridged with newly formed bone; while the defects of the control side were remained empty.Tetracycline fluorescence microscopy and hisotological examination could confirm the new bone tissue formation in the experimental side. The ink staining in new bone specimens suggested that there were abundant of neovasculization in tissue-engineered bone.CONCLUSION: Tissue-engineered periosteum can form new bone in allogenic rabbits and can be vascularized by some inherent mechanism for new bone tissue survivor.