An experimental study for the functional recovery of injured spinal motoneurons

We investigated the influences of neurotrophic factor on injured motoneurons in acute spinal cord injury models.Our study consists of the following two experimentsExperiment 1.25 Wister rats were used in this experiment。An incomplete spinal cord injury model was created by placing a20-g weight on the dura mater at the C6level for 5min(n=20).The cervical spinal cord was remove at post-injury day 3，7，14，28，and frozen sections were stained for p-75.The number of p-75 positive motoneurons were counted.(Results)There were no p-75 positive motoneurons in the sham group(n=5)。In the injury group，p-75 positive motoneurons were recognized at post-injury day 3，highly increased at day 7，and hardly observed by at day 14，28.Experiment。2；20 incomplete spinal cord injury models were created in the same manner.In10glial cell line-derived neurotrophic factor(GDNF)was injected into the subarachnoid space immediately after the injury，and phosphate buffer saline(PBS)was injected n the other10 animals.Motor function was evaluated at post-injury day 2 and 7.The spinal cord was removed from both groups7days after the injury.The sections were immunofluorescence stained for choline acetyltransferase(ChAT)。ChAT fluorescence was measured with a microphotometry system。(Results)Motor function evaluation：Both the GDNF group and the PBS group were able to maintain their trunk on the inclined plane up to a mean angle of 82°before the injury.On post-injury day2 the angle at which they，were able to maintain their trunk had decreased to 55°and 52°，respectively，and on day7，to 68°and 63°respectively.The deference on post-injury day 2was not significant，but a significant deference was observed by day7.Immunohistochemical findings：The fluorescence values in both injured groups were lower than in the uninjured group，but the reduction in fluorescence that occurred in the GDNF group was a significantly prevented。

We investigated the influences of neurotrophic factor on injured motoneurons in acute spinal cord injury models. Our study consists of the following two experimentsExperiment 1.25 Wister rats were used in this experiment. An incomplete spinal cord injury model was created by placing a 20-g weight on the dura mater at the C6 level for 5 min (n=20) .The cervical spinal cord was remove at post-injury day 3,7,14,28, and frozen sections were stained for p-75 .The number of p-75 positive motoneurons were counted. (Results) There were no p-75 positive motoneurons in the sham group(n=5). In the injury group, p-75 positive motoneurons were recognized at post-injury day 3, highly increased at day 7, and hardly observed by at day 14, 28.Experiment. 2; 20 incomplete spinal cord injury models were created in the same manner. In 10 glial cell line-derived neurotrophic factor(GDNF) was injected into the subarachnoid space immediately after the injury, ,and phosphate buffer saline (PBS) was injected n the other 10 animals. Motor function was evaluated at post-injury day 2 and 7. The spinal cord was removed from both groups 7 days after the injury. The sections were immunofluorescence stained for choline acetyltransferase (ChAT). ChAT fluorescence was measured with a microphotometry system. (Results) Motor function evaluation: Both the GDNF group and the PBS group were able to maintain their trunk on the inclined plane up to a mean angle of 82゜before the injury. On post-injury day 2 the angle at which they, were able to maintain their trunk had decreased to 55゜and 52゜, respectively, and on day 7, to 68゜and 63゜ respectively. The deference on post-injury day 2 was not significant, but a significant deference was observed by day 7. Immunohistochemical findings: The fluorescence values in both injured groups were lower than in the uninjured group, but the reduction in fluorescence that occurred in the GDNF group was a significantly prevented.