CHINESE JOURNAL OF CLINICAL REHABILITATION,2005年9(29):225-227 ISSN：1671-5926
北京联合大学继续教育学院;昆明医学院解剖教研室;Department of Anatomy
BACKGROUND: Neurotrophin-3 (NT3) and neurotrophin-4 (NT4) play an important role in the growth, survival and functions of neurons in vivo or in vitro. However, it has not been reported whether they can protect and repair neurons of spinal cord after crushed spinal cord injury (cSCI).OBJECTIVE: To explore the expression of NT3 and NT4 in ventral and dorsal horns of spinal cord at various time points after cSCI and analyze the pattern of expression changes.DESIGN: Randomized controlled study and single analysis of variance.SETTING: Continuing Education College of Beijing Union University;Department of Anatomy, Kunming Medical College.MATERIALS: The experiment was conducted in the Institute of Neuroscience of Kunming Medical College from January to March 2003.Totally 24 adult SD rats were divided randomly into 4 groups: control group, 24-hour cSCI group, 7-day cSCI group, and 21-day cSCI group with 6 rats in each group.METHODS: After anesthesia, rats in each cSCI group were dissected at vertebra T11 and crushed at spinal cord T13. After 24 hours, 7 days and 21days, the rats were killed respectively by cutting their heads off, and spinal cord L1-L3 was taken out to make frozen transactional slices of 20 μm.Rats in control group received no treatment and were killed at the same time point as those in 24-hour cSCI group, and the process of slice making was the same as mentioned above. The distribution of NT3 and NT4 positive cells in the spinal cord ventral and dorsal horns of adult rats was observed, and NT3 and NT4 positive nucleus in the ventral and dorsal horns of the same areas were counted.neurons in the rats' spinal cord ventral and dorsal horns.products were mainly stained in nucleus while NT4 was stained in horns of spinal cord in each group: The number of positive neurons in the ventral horn was significantly greater in 7-day and 21-day cSCI groups than in control and 24-hour cSCI groups (10.2±1.1, 11.4±3.2, 6.2±1.8, 7.4±2.4, P<0.01). The number of positive neurons in the dorsal horn in 21day group was significantly greater than that in control group (86.4±9.8,71.3±8.3, P<0.01); however, it was remarkably lower in 24-hour and 7day cSCI groups than in control group (48.5± 5.1, 41.5±3.7, 71.3± 8, P cord in each group: The number of positive neurons in the ventral horn was significantly higher in 24-hour, 7-day and 21-day cSCI groups than in control group (9.4±2.8, 10.8±2.7, 15.1±4.0, P<0.05); and it assumed an increasing tendency as time went by (P<0.05). By contrast, the number of positive neurons in the dorsal horn in 7-day and 21-day groups was significantly higher than in control and 24-hour groups (28.1±3.1,35.1±4.4, 23.3±2.3, 24.1±1.8, P<0.01), and it would increase with time following cSCI (P<0.01).CONCLUSION: The number of NT3 and NT4 positive neurons increases in spinal cord ventral and dorsal horns after cSCI, suggesting that endogenous NT3 and NT4 have effect at different time on sensory and motor neurons in the repair of spinal cord injury.