ABSTRACT
Objective To establish a rat model of spinal root avulsion and to validate the model by brain-derived neurotrophic factor(BDNF)treatment. Methods To evaluate the motor neuron loss,5 male SD rats were used to undergo spinal root avulsion surgery. One week later, the number of motor neurons in the ventral horn of the spinal cord was as-sessed by histopathology using immunohistochemical staining with a choline acetyl transferase(ChAT)antibody. After this pilot study,40 male SD rats at 7 weeks of age were randomly divided into 4 groups:two control groups,BDNF preventive and treatment groups. Results All rats recovered well post-surgery and no obvious abnormality was observed. Compared with the contralateral side,the number of motor neurons in the ipsilateral avulsed side was significantly decreased at one week after surgery(20.06%,P<0.05). Compared with the control group,there was a significant increase in ChAT posi-tive neurons in the BDNF preventive group(17.85% vs. 93.06%,P<0.0001)or BDNF treatment group(1week after surgery)(26.94% vs. 86.87%, P<0.0001), indicating that the motor neurons were effectively protected by BDNF. Conclusions A rat model of spinal root avulsion is successfully established,which can be valuable for studies of amyotro-phic lateral sclerosis and drug discovery efforts.
ABSTRACT
The accessory nerve is traditionally described as having both spinal and cranial roots, with the spinal root originating from the upper cervical segments of the spinal cord and the cranial root originating from the dorsolateral surface of the medulla oblongata. The spinal and cranial rootlets converge before entering the jugular foramen or within it. This conventional view has been challenged by finding no cranial contribution to the accessory nerve. Clinical, anatomical, functional and evolutionary implications are discussed in the present study.
Subject(s)
Skull/anatomy & histology , Skull/metabolism , Accessory Nerve/anatomy & histology , Accessory Nerve/physiology , CadaverABSTRACT
Objective To compare the effect of natural antioxidants TA9001 and EGb761 on c-jun, NOS expression and survival of spinal motoneurons following brachial roots avulsion. Methods One hundred and eighty adult Sprague-Dawley female rats were randomly divided into TA9001, ECb761 and control groups. The right C 5～T 1 nerve roots were avulsed and then the introperitoneal injection of 1ml of 0.5% TA9001, 0.5% EGb761 or normal saline was given immediately and once daily to the rats, respectively. The rats were killed after survival for 4 h, 12 h 1 d,3 d,5 d,and 1 week, 2 weeks, 4 weeks and 6 weeks. The cryostat sections of C 7 segment were prepared and carried with c-jun immunocytochemistry, NADPH-d histochemistry and neutral red counter stain. Results The c-jun and nNOS gene expression was only appeared in injured motoneurons. c-jun was first appeared at 4 h, reached its maximum at 1 d, and grandually decreased till 2 weeks. NOS was first checked at 5 d, mostly at 2 weeks and decreased until 6 weeks. Avulsed motoneuron death started at 2 weeks, reached its peak at 4～6 weeks. Both TA9001 and EGb761 can cause c-jun up-regulation, nNOS down-regulation and more motoneuron survival as compared to control. Furthermore, EGb761 had more power to enhance c-jun expression than TA9901 at each time point. Conclusion It seems that nNOS is more important in motoneuron death mechanism than c-jun. Treatment of either TA9901 or EGb761 can protect the injured motoneurons following root avulsion.
ABSTRACT
To identify the corresponding cord segment for each root at the level of conus medullaris, a dissecting microscopic study was carried out on the spinal cord of 14 adult cadavers. We measured following contents:1) the longitudinal extent of the medullary segment of origin of each root:2) the distance from the lowest rootlet of the conus to the highest portion of the medullary segment of each root:3) the distance from the conus tip to the lowest portion of the medullary segment of each root:4) the morphological features of root-spinal cord juncton, intrathecal anastomoses, and others. We measured on the basis of the last rootlet ecause of no clear distinction between the conus and filum terminale. Our values showed considerable variation from one case to another. The average length of the whole lumbar and sacral segment was 50 mm and 30 mm, respectively. The S-1 root was the largest. Intrathecal intersegmental anastomoses were found in all cases examined, and usually consisted of small caliber rootlets connecting the spinal roots of adjacent segments. We emphasize the importance of microsurgical structure of conus medullaris when performing an operation of dorsal root entry zone or myelotomy for the relief or spasticity or intractable pain of lower extremities.