ABSTRACT
AIM: To investigate the influence of EGb761 on NOS expression and survival of motoneurons after spinal root avulsion.METHODS: Eighty adult SD female rats were randomly divided into control and EGb761 groups. The C5-T1 nerve roots of right brachial plexus were avulsed and injection of 1 mL of either EGb761 25 mg?kg -1 ?d -1 or normal saline (ip) was performed everyday. The treated rats were killed 1 week, 2 weeks, 4 weeks and 6 weeks following avulsion. The cryostat sections of C7 segment of every rat were collected and carried with NADPH-d histochemistry plus neutral red counterstain. The difference of the numbers of both NOS-positive and survival motoneurons were quantitatively studied. RESULTS: Following avulsion, NOS was expressed in avulsed motoneurons at 1 week, reached to its maximum at 2 weeks and then decreased gradually from 4 weeks to 6 weeks. Motoneurons died from 4 weeks to 6 weeks. With EGb761 treatment, the number of NOS-positive motoneurons were decreased at each time point and the number of survival motoneurons was increased at each time point compared to control rats.CONCLUSIONS: EGb761 protected the spinal cord motoneurons from avulsion injury. This effect may be related to inhibition of NOS expression.