Satellite Cells of Sensory Neurons after Various Types of Sciatic Nerve Trauma in the Rat

Sciatic nerve crushing, transection, and ligation models were used in rats to study the reactions of and changes in the numbers of satellite cells (SC) in spinal dorsal root ganglia in the lumbar segment. Nerve transection was followed by the appearance of neurons surrounded by two layers of SC. The thickness of SC processes and the areas of contacts with neurons increased as a result of invaginations into neuron perikarya. After nerve ligation, SC and their processes were located around parts of large and intermediate neurons in several tightly appressed layers; the area of contact between SC and neuron perikarya showed increased development of invaginations such that lamellar structures appeared in the SC cytoplasm, along with contacts with SC processes surrounding neighboring neurons. The greatest increases in SC numbers were seen after ligation of the nerve. Transection was followed by increases in the numbers of small and intermediate neurons surrounded by vimentin-positive SC. The number of large neurons surrounded by these cells decreased. At all time points following ligation of the nerve, all neurons in the study ganglia were surrounded by vimentin-positive SC. Post-traumatic changes in structure and numbers differed in SC associated with sensory neurons of individual size populations and depended on the type of trauma applied to efferent conductors.