Ultrastructure changes of sensory neurons in the spinal dorsal horn after chronic constriction injury of the sciatic nerve in rats

Objective To observe the ultrastructure changes of sensory neurons in the spinal dorsal horn after chronic constriction injury(CCI) of the sciatic nerve in rats.Methods 20 adult male SD rats were randomly divided into normal group and operation group.The CCI model was established by ligaturing left sciatic nerve in the operation group.On the 3rd,7th and 14th days after surgery,the ultrastructure of sensory neurons in the left spinal dorsal horn of L_(4～6) was observed by transmission electron microscopy,and the numbers of sensory neurons in L_(4～6) spinal dorsal horn were counted by the light microscopy with HE staining.Results The numbers of sensory neurons on the injured side of the spinal dorsal horn were decreased significantly when compared with the normal side(P0.05) and their dead rate reached 23%on the 2nd week. Different morphological characteristics,mainly apoptosis,were observed in sensory neurons in L_(4～6) left spinal dorsal horn on day 7 and day 14 after CCI.Conclusion After sciatic nerve injury,sensory neurons in L_(4～6) spinal cord dorsal horn are lost,and their morphological changes, mainly apoptosis,are diverse.